Glossary of Automotive Terms – S

Letter S – Dictionary of Automotive Terms

  1. A letter rating for tires to indicate that they are theoretically rated for speeds up to 180 kph (110 mph), as in P220SR15. The next higher rating is T.
  2. Abbreviation for Special or Sport, indicating better performance than a standard car model.
Honda S2000Click image for books on
Honda S2000

A model of automobile manufactured by Honda

Abbreviation for Selectable Four Wheel Drive
An API classification for straight mineral oil used in early gasoline and diesel engines which are operated under such mild conditions that the protection of compounded oils is not required. This category has no performance requirements, and oils in this category should not be used in any engine unless specifically recommended by the equipment manufacturer. It was replaced by the obsolete SB. Modern gasoline engines should use oil that meets the SM classification.
SaabClick image for books on

A model of automobile manufactured in Sweden and includes 9-2X (2005-06), 9-3 (1999-current), 9-5 (1999-current), 9-7X (2005-07), 900 (1978-98), and 9000 (1985-98)

Sacco panels
Sacrificial anode
An electropositive metal coating, such as aluminum or zinc, that protects the steel of a car body by corroding first when attacked by electrolytic action
Sacrificial protection
  1. Seat on a bicycle
  2. Metal piece on a centerpull brake.
  3. Upper main bearing seat

A large bag or one of a pair which hangs down from the saddle or straddles the rear wheel of a bicycle or motorcycle. Also called panniers

Saddle gel
A gelatin substance that is inserted into a bicycle or motorcycle saddle beneath the leather cover to provide more cushioning.
Saddle tank
  1. A fuel tank mounted above the rear axle.
  2. A fuel tank that fits over the top tube of the frame of a motorcycle
Saddle valve
Saddle valveSaddle valve

A device that is silver brazed or clamped on a tubing line or pipe where a spike punctures the line or a hole is drilled in the line to provide a secondary outlet of the liquid in the line. Also called tap-a-line

Abbreviation for Society of Automotive Engineers. It publishes automotive research papers and defines various automotive standards of measurement.
SAE gross bhp
An older unit of engine power. In the SAE gross bhp test, a bare engine is used, i.e., an engine equipped with only those accessories that are necessary for its operation, such as the oil pump and fuel pump; but water pump, alternator, exhaust system, etc. are not used; this results in a higher power rating than achievable by the same engine under real operating conditions
SAE gross horsepower
A production engine’s actual power available at the flywheel or output shaft (usually crankshaft) as tested with an absorption dynamometer. It differs from SAE net horsepower in that many of the accessories (such as alternator, water pump, etc.) are not attached. Engines before 1973 were primarily measured with these ‘gross’ numbers. Since 1973, net figures were published. This confusion caused many people to suppose that their engine had been seriously de-tuned when they saw that the same engine in 1972 had 400 hp but in 1973 had only 235 hp. (This example is from the Cadillac 500 cubic inch engine). Compare SAE net horsepower.

SAE horsepower
A simple formula of long standing is used to determine horsepower. The formula is (bore diameter) squared times (number of cylinders) divided by 2.5. This formula is used primarily for licensing purposes and is not very accurate for determining actual brake horsepower. Also called rated horsepower. Compare SAE gross horsepower and SAE net horsepower.

SAE net bhp
A newer unit of engine power. A fully-equipped engine (as when installed in a vehicle) is used to determine SAE net bhp figures; as a rough guideline, SAE net is about 70-85 percent of SAE gross
SAE net horsepower
The brake power (power available at the flywheel or output shaft — usually the crankshaft) of a fully equipped engine fitted with all the accessories necessary to perform its intended functions unaided. In 1973, automobile manufacturers began publishing their engine specifications in net horsepower and net torque instead of gross figures. In many cases the published numbers were significantly lower in 1973 than in 1972. Some of the decrease was attributed to the addition of pollution equipment, the lowering of compression, and the use of regular unleaded gasoline instead of premium leaded fuel. However most of the decrease in number was a switch to net figures. Compare SAE gross horsepower.

SAE Specifications
Standards developed by the Society of Automotive Engineers, Inc.
SAE Standard Screw Threads
The SAE Screw Thread Standard, as revised in 1954, conforms with the Unified and American Standard.
SAE steels
A numerical index used to identify composition of SAE steel
Safe headway
A safe distance between two vehicles on the road
Safe stop wheel
A Run-on tire
Abbreviation for Safe, Accountable, Flexible, and Efficient Transportation Equity Act – a Legacy for Users
Safety Act
Safety, active
Safety Administration
Safety bead seat
A general term for a safety contour on the rim bead seat preventing the tire bead from sliding into the rim well especially during cornering maneuvers
Safety belt
Safety Board
Safety can
  1. Approved container of not more than 5-gal. capacity. It has a spring-closing lid and spout cover. It is designed to relieve internal pressure safely when exposed to fire.
  2. An approved container of not more than two gallons capacity having a spring-closing lid and spout cover and so designed that it will safely relieve internal pressure when subjected to fire exposure.
Safety catch
A secondary latch usually located under the front edge of the hood, near the center, which prevents accidental release of the hood if the main cable-operated hood lock is activated by mistake
Safety chains
Safety chainsSafety chains

Two, crossed chains linking the trailer and vehicle frame as a safeguard if the towing hitch fails

Safety Compliance Certification Label
(SCC) An American label which must be attached to the lower half of the left-hand front door lock facing; specifies the VIN and other relevant information
Safety control
  1. Device to stop the operation of a unit if unsafe pressure, temperatures, and/or dangerous conditions are reached.
  2. Automatic controls and interlocks (including relays, switches, and other auxiliary equipment) which are intended to prevent unsafe operation of the controlled equipment.
Safety-control circuit
A circuit or portion thereof involving one or more safety controls aimed at preventing unsafe operation of the controlled equipment due to grounding, opening or shorting of any part of the circuit.
Safety Cutout
Safety Data Sheets
Safety factor
  1. Providing strength beyond that needed, as an extra margin of insurance against part failure.
  2. Degree of strength above normal requirements which serves as insurance against failure
Safety features
Safety glass
Safety goggles
Safety gogglesSafety goggles

A close-fitting glasses or mask to protect the eyes (e.g., during welding)

Safety harness

Safety hub
A device that is installed on the rear axle to prevent the wheels from leaving the vehicle in the event of a broken axle.
Safety hubs
Safety ledge
A raised area (hump) around the circumference of the bead seat area of passenger wheels. Its function is to prevent the tire beads from becoming unseated during hard cornering or while running with low air pressure. A must with tubeless passenger tires. Also called Special ledge
Safety motor control
Electrical device used to open circuit to motor if temperature, pressure, and/or current flow exceed safe conditions.
Safety pin
Safety pinSafety pin

A securing device

Safety plug
Device which will release the contents of a container before rupture pressures are reached.
Safety pressure cap
Safety reflector
Safety relief valve
A spring-loaded valve designed to open and relieve excessive pressure in a device when it exceeds a predetermined safe point
Safety rim
A rim having two safety ridges, one on each lip, to prevent the tire beads from entering the drop center area in the event of a blowout. This feature keeps the tire on the rim.
Safety seat
Safety shutdown
The action of shutting off all fuel and ignition energy to the fuel utilization equipment by means of a safety control or controls such that restart cannot be accomplished without manual reset.
Safety shutoff device
A device that will shut off the fuel supply to the controlled burner in the event the source of ignition fails. This device may interrupt the flow of fuel to the main burner only, or to the pilot and main burner under its supervision.
Safety stand
Safety standSafety stand

A device that can be securely locked at a choice of heights, so it can be placed under a specific part of the vehicle underbody to support the weight of the vehicle that has been raised with a jack, and keep the vehicle safely in place. Usually used in pairs. Also called jack stand or axle stand

Safety steering column
Safety strap
Safety switch
Safety valve
  1. A valve designed to open and relieve the pressure within a container when container pressure exceeds a predetermined level.
  2. Self-operated, quick opening valve used for fast relief of excessive pressures.
Safety valve shutoff
A valve that is automatically closed by the safety control system or by an emergency device. Such valve may be of the automatic or manually opened type.
Safety Vehicle
Safety wheel
A general term referring to either a wheel with a safety bead seat or a wheel with run flat properties
Abbreviation for Separator assembly-fuel Vacuum
  1. To bend or droop under weight or pressure. As a result of a front or rear end collision, the frame may develop a sag in the middle, much like a hammock.
  2. To fail to meet projected sales.
  3. A paint problem.
  1. An aggravated condition of paint where a band of paint runs down the side of a vertical area of the body. It may be caused by excessive build-up of paint, thinners which are too slow-acting, or excessively slow movement of the spray gun.
  2. The straining of a ship that tends to make the middle portion lower than the bow and stern
Sagging door
A door that sits too low in the door opening which is often indicated by an uneven door gap that widens towards the rear bottom and front top of the door but narrows down at the rear top and front bottom. This condition may be caused by faulty setting of the door hinges and lock/striker assembly. On convertibles, it often pinpoints structural damage, because the chassis may be bending in the middle
An aggravated condition of paint where a band of paint runs down the side of a vertical area of the body. It may be caused by excessive build-up of paint, thinners which are too slow-acting, or excessively slow movement of the spray gun
Sag wagon
A support vehicle for touring bicycles or motorcycles to provide food, repairs, or a ride home.
Abbreviation for Steering axis inclination
Sail Panel
The somewhat triangular panel behind the rear side window as the final support for the roof. Also called quarter window.
Sainte Claire
Abbreviation for Secondary Air Injection System
Salable natural gas
Natural gas marketed under controlled quality conditions.
SALA suspension
Abbreviation for Short arm/long arm suspension
Total automotive product sales (vehicles, automotive parts, including OE and aftermarket).

Sales value
Salient pole
An electric motor has salient poles when its stator or field poles are concentrated into confined arcs and the winding is wrapped around them (as opposed to distributing them in a series of slots)
A British term for sedan
Salt brine recycling
Collecting brine runoff and reusing it as a pre-wetting agent for salt
Salt flat
Salt marsh of very unreliable consistency and bearing strength found in desert regions and characterized by a top crust of varying thickness and strength with soft salt mud of great depth beneath it.
Salt fog testing
Salt spray chamber
A test chamber for Salt spray testing
Salt spray testing
Spray tests with sodium chloride solutions
Salt water splash
An open-air corrosion test facility
A vehicle totaled in an accident and then repaired. There is no guarantee of street worthiness for a salvaged vehicle. It may look good, but be hazardous to drive.
Sam Browne
A wide strap, made of reflective material, worn around the waist with a strap diagonally over the right shoulder
  1. To smooth or clean a surface by rubbing with sandpaper. Sanding usually refers to hand tools such as sandpaper and block, while grinding always refers to power tools such as angle grinders.
  2. A term popularly applied to loose, unconsolidated accumulations of detrital sediment, consisting essentially of rounded grains of quartz. In the mechanical analysis of soil, sand, according to international classification, has a size between .06 and 2.0 mm.
  3. To apply a thin layer of sand or sand and salt to an icy road surface to increase traction.
Sand blast
Cleaning by the use of sand propelled at high speeds in an air blast.
Sand blaster
Sand blasterSand blaster

A metal box into which a rusty or dirty object is placed. Compressed air and sand or grit are forced through a nozzle and is directed at the object in order to remove the dirt, paint, or rust.

The cleaning of a surface with a jet of sand (or grit) under air or steam pressure
Sand casting
The formation of shapes by pouring molten metal into a cavity shaped in sand in a molding flask
Sand channels
Open face tubes or planks (sometimes articulated) with a rough inner surface with ridges used to put under the driving wheels to assist in gaining traction when the vehicle is stuck in soft sand.

A power-driven tool with a rotating abrasive disc for smoothing and cleaning surfaces.

Sanding block
A block of rubber or plastic to which the sandpaper is fastened, offering the operator a good grip. The block should be used for most sanding jobs because it distributes the pressure evenly and gives a more uniform surface.
Sand ladders
A pair of aluminum ladders, about 170 cm long, specially made with rungs closer than normal, to lay beneath the vehicle wheels in soft sand to give grip and flotation.

An abrasive paper coated with sand for smoothing and cleaning. Compare Glasspaper
Sand recycling
Collecting road sand used one winter and processing it for reuse the next winter or for other applications
Sand scratch
Sand scratches
The marks left in metal or in the old finish by abrasives. They may also show in the finish coat due to lack of filling or sealing.
Sand scratching
A paint fault characterized by the paint film appearing low in gloss and showing primer and metal imperfections in the top coat; may be caused by excessively coarse sanding and too thin a paint coat
Sand scratch swelling
Solvents present in surface scratches that cause the old finish to swell.
Sand tires
An off-road tire designed for desert sand and beach sand. Usually with smooth tread blocks rather than the sharp, bold blocks of a mud tire.
Sand tracks
Generic name sometimes given to any item fulfilling the role of a sand ladder. May be pierced steel planking

Sandwich construction
A composite construction of alloys, plastics, and other materials consisting of a foam or honeycomb layer and glued between two hard outer sheets. Also called Sandwich laminate
Sandwich laminate

  1. Abbreviation for Scandinavian Automotive Suppliers
  2. Abbreviation for speed adjusting screw
Abbreviation for self-addressed stamped envelope. Often used in advertisements where the seller will provide information if potential buyers will send a SASE enclosed in their query letter.


A block of controls near the steering wheel rim.

Saturated vapor
Vapor condition which will result in condensation into droplets of liquid if vapor temperature is reduced.
Condition existing when substance contains all of another substance it can hold for that temperature and pressure.
Saturation period
The length of time the breaker points are closed and current is flowing through the primary windings of the coil.
SaturnClick image for books on

A make of automobile manufactured by General Motors. Includes

  • Aura (2007-current)
  • Ion (2003-07)
  • L100 (2001-02)
  • L200 (2001-03)
  • L300 (2001-05)
  • LS (2000)
  • LS1 (2000)
  • LS2 (2000)
  • LW1 (2000)
  • LW2 (2000)
  • LW200 (2001-03)
  • LW300 (2001-03)
  • Outlook (2007)
  • Relay (2005-07)
  • SC (1991-92)
  • SC1 (1993-02)
  • SC2 (1993-2002)
  • SKY (2007-current)
  • SL (1991-2002)
  • SL1 (1991-2002)
  • SL2 (1991-2002)
  • SW1 (1993-99)
  • SW2 (1993-2001)
  • VUE (2002-07)
Saturn Aura Green Line
A midsize Hybrid sedan produced by General Motors similar to the Chevrolet Malibu Hybrid that uses a Belt Alternator Starter (BAS) hybrid system.
Saver spare
Saver wheel
Saving tire
Abbreviation for Spark Advance Vacuum Modulator
Abbreviation for Spark Angle Work
Saybolt Furol viscosity
A viscosity test similar in nature to the Saybolt Universal viscosity test but one more appropriate for testing high-viscosity oils. Certain transmission and gear oils, and heavy fuel oils are rated by this method. The results obtained are approximately 1/10th the viscosity which would be shown by the Saybolt Universal method.
Saybolt viscometer
An instrument used to determine the fluidity or viscosity of an oil.
An API designation for older minimum-duty gasoline engines operated under such mild conditions that only minimum protection is given. Oils of this designation have been used since the 1930s and provide mild antiscuff capability and resistance to oil oxidation and bearing corrosion. It was a replacement for SA designated oil and was replaced by SC oil. SB oil should not be used in any modern engines. Instead, use the most current SM designated oil.
Abbreviation for Service Bay Diagnostic System
Abbreviation for Single Board Engine Controller (replaced by PCM)
Abbreviation for Steel belted radial
  1. Abbreviation for Boost Solenoid (Ford)
  2. Abbreviation for Seat-integrated belt system
Abbreviation for Serial Bus Traveler
  1. Abbreviation for Supercharged Engine
  2. An API oil designation for typical gasoline engines of 1964 to 1967 and replaces the SB designated oil. Oils designed for this service provide control of high and low temperature deposits, wear, rust, and corrosion in gasoline engines. It was later superseded by SD designated oil. However, engines of that vintage can now use the modern SM oil.
Scab corrosion
A scab-like corrosion occurring along a scratch in a coating
  1. The accumulation of rust and minerals within the cooling system.
  2. A discoloring or oxidation on the surface of hot forged metal objects.
  3. A series of evenly spaced marks or values used to represent the quantity or quality of something.
Scale free system
Eliminates deposits in condensers by picking up electrical energy from water, allowing deposits to be carried through the system and disposed.
Scale rust
Loose, flaking rust
A feature of modern radios which plays a few moments of each station before proceeding to the next one. Also called Frequency scan button
Scan button
A radio button which, when pressed, causes the tuner to scan the frequencies of stations with sufficient signal strength and plays that station for about 5 seconds before going to the next one. When the driver or passenger wants to listen to the currently played selection, he can press the same button (or a different one) to select that station. Also called Frequency scan button
A nickel-silicon-carbide coating for particularly wear-resistant cylinder walls. Compare Nicasil
Scan tool
A device that interfaces with and communicates information on a data link
Abbreviation for Silicone Capacitance Absolute Pressure Sensor (Ford)
Abbreviation for South Coast Air Quality Management District.
Scatter shield
A steel or nylon guard placed around the bell or clutch housing to protect the driver and spectator from flying parts in the event of part failure at high rpm. Such a shield is often placed around the transmissions and differential units.

A feature in a two-stroke engine to clear away or expel exhaust gas from a cylinder and to fill the cylinder with a fresh charge. These processes take place simultaneously in a two-stroke engine.
Scavenger pump
Mechanism used to remove fluid from sump or container.
The removal of the exhaust gases from the cylinder by using the momentum of the exhaust gases in a long exhaust pipe or by taking advantage of the pressure waves set up in the exhaust pipe by the discharge of the gases.

Scavenging efficiency
In a two-cycle engine, the ratio of a new air charge, trapped in the cylinder, to the total volume of air and exhaust gases in the cylinder at port closing position.
Scavenging jet
The jet of fresh charge supplied into the cylinder, the shape and direction of which determine the effectiveness of the scavenging process
Scavenging losses
If the exhaust gases remain in the cylinder, they prevent a full charge of fresh mixture from entering; the power output is thus reduced
Scavenging passage
The passage inside a two-stroke engine that serves to scavenge the exhaust gas from the engine; in most cases it refers to the transfer passage, as the gas column supplied across the transfer port initiates the scavenging process
Scavenging picture
In experimental two-stroke engine development, a map of the scavenging air velocity distribution and the scavenging jet orientation inside a cylinder
Scavenging Port
Scavenging pump
An oil pump in a dry sump system which returns oil from the crankcase to the main oil reservoir
Scavenging system
A method used to accomplish the charge-changing process in a two-stroke engine
Scavenging valve
In evaporative emission control systems, a valve in the purge line between the activated charcoal canister and inlet manifold which controls the purge air flow that regenerates the charcoal filter
Abbreviation for Supercharger Bypass
  1. Abbreviation for Spark control computer.
  2. Abbreviation for Safety compliance certification
A drawing system for portraying the components and wires in a vehicle electrical system using standardized symbols
Schematic electrical diagram
A diagram showing, by means of graphic symbols, the electrical connections and functions of a specific circuit arrangement. The Schematic Diagram facilitates tracing the circuit and its functions without regard to the actual physical size, shape or location of the component devices or parts.
Schematic – Ladder Form electrical diagram
A diagram drawn in the form of a vertical ladder. The outer vertical lines represent the electrical supply conductors. The horizontal steps represent each individual circuit with all component devices or parts.
Schnürle scavenging
School Bus
Any bus contracted by any public or private school or school district to provide transportation to its pupils.

Schrader valve
Schrader valveSchrader valve

  1. A valve with a spring-loaded pin, in which the pin is depressed to open the valve. It is used at each automobile tire, most air conditioning systems, and on some fuel injection systems. Schrader is the original manufacturer of this type of valve.
  2. A spring-loaded valve which permits air or fluid flow in one direction when a center pin is depressed and holds it back when a pressure difference exists.
  3. A bicycle tire valve similar to the type found on automobile tires. Compare Presta valve.
  4. A spring loaded valve, similar to a tire valve, located inside the service valve fitting to hold refrigerant in the system. Special adapters with built-in depressors must be used to attach service hoses to Schrader valves.
Scientific Research and Experimental Development Program
(SR&ED) This program provides generous incentives for industrial research and development in Canada. The program allows individuals and companies to deduct 100 percent of qualified current SR and ED expenditures and capital SR and ED expenditures.

An automobile manufacturer as a division of Toyota, founded in 2002. Includes tC (2005-current), xA (2004-06), xB (2004-current), and xD (2008-current)

Scissors Dump
A dump truck with a special hydraulic system.
Scissors jack
Scissors jackScissors jack

A device for lifting a corner of the vehicle. As it is applied, the arms are in the shape of the letter X or a diamond.

Scissors Lift
A cargo body which is used to lift materials to a higher surface, such as lifting shingles to a roof.
  1. A two-wheel motorcycle usually with a small engine and a step-through frame.
  2. A small three or four wheeled vehicle designed for a disabled person and is usually powered by two 12-volt batteries (producing 24 volts). Called a mobility scooter.
A colloquial term for Oscilloscope
  1. A scratch or groove on a finished surface. It is usually caused by dirt or some other object which mars the Finish. cylinder walls, for instance, can be scored by broken rings or a Piston pin clip which has come loose.
  2. (SCORE) An abbreviation for Supplier Cost Reduction Effort.
A brake disc that is scratched, grooved, or lined with small cuts
  1. Grooves or deep scratches on a friction surface caused by metal-to-metal contact (worn-out brake pads or shoes) or debris caught between the friction material and the friction surface.
  2. Irregular grooves in the friction surfaces of brake drums or rotors caused by contamination or worn-out linings.
Scotch yoke
Mechanism used to change reciprocating motion into rotary motion or vice-versa. Used to connect crankshaft to piston in refrigeration compressor.
Abbreviation for Standard Corporate Protocol
  1. Abbreviation for Silicon Controlled Rectifier.
  2. Abbreviation for Selective Catalytic Reduction
  3. Abbreviation for Segregated Cycle Route
Scramble crosswalk
scramble crosswalk
Scramble crosswalk

A pedestrian scramble crosswalk allows an intersection to act as a six-way crossing, letting pedestrians walk diagonally across the intersection by halting all vehicular traffic. Also called priority crossing

Waste metal
Scrap dealer
A person or company which collects and recycles metal, especially from unusable vehicles.
Scraper ring
An Oil scraper ring
Scrap metal
Metal from unusable vehicles
Scrap pile
Discarded Tire casings having service life exhausted through wear or damage.
A vehicle registered in the previous year but not re-registered in the current year.
Scrap yard
The premises of a dealer in scrap metal
Scratch swelling
Slang for a high-performance car, possibly due to the reaction of passengers with an over-enthusiastic driver.
To shield from electrical interference.

Screen bulkhead
Light nonwatertight transverse bulkhead fitted in some Great Lakes ore carriers
The process of mechanically sifting used road sand through a mesh to separate out particles and debris so that the sand can be reused
  1. A spiral path along a cylinder.
  2. A fastening device sometimes used incorrectly for a bolt. Screws can be one of four major types:
  3. A screw is like an Inclined plane wrapped up. It can take a rotating force and change it into a much larger straight-line force.
Screw body
The blank portion of the bolt or screw which is between the thread and the head.
Screw clamp
A hose fastener composed of a band with a series of slots to allow the thread of a screw to move up and down the band.

A device used to remove or install screws.

Screwdriver bit
A hex shank with a screwdriver tip at one or both ends to loosen and tighten recessed screws; designed for use with magnetic or power-driven screwdrivers
Screw extractor
A device used to remove broken bolts, screws, etc., from holes.
Screw-holding screwdriver
A tool used to hold screws for easy placement in extremely tight places; also appropriate for loosening and tightening
Screw machine
Cutting and removing material in order to form a fastener.

Screw pitch gauge
A measuring tool used to identify thread sizes, featuring a selection of blades with different thread profiles to determine screw pitch
Screw pump
  1. Compressor constructed of two mated revolving screws.
  2. Pump having two interlocking screws rotating in a housing.
Screw starter
A tool used to hold screws for easy placement in extremely tight places; also appropriate for loosening and tightening
Screw Stock
Metal in the form of wire or rod, ordinarily a free-machining type of alloy, used for making screw machine products.
A ridge of uniform section in the form of a helix on the external or internal surface of a cone or frustum of a cone. A thread formed on a cylinder is known as a straight or parallel thread, to distinguish it from a taper thread which is formed on a cone or frustum of a cone.

Screw Thread Chasers
Cutting tools having teeth spaced to match the pitch of the threads to be cut.
To cut or scratch with a pointed instrument, e.g., (in) a painted surface, for testing purposes or to mark the position of a part
A pointed steel hand tool for marking metal
A plastic screw-rivet which secures trim
Flue-gas desulfurization unit equipment used to remove sulfur oxides from the combustion gases of a boiler plant before discharge to the atmosphere. Chemicals such as lime are used as the scrubbing media.

A heavy wear on a tire caused by sliding sideways across the road surface, as when skidding
Scrub coat
Road crews apply a liquid asphalt and sand mixture to fill holes and ruts in a road’s surface. This process is usually done prior to repaving a road.
Scrub radius
The distance from the point where the Steering axis intersects the ground to the longitudinal line that runs through the center of the tire’s Contact patch. Also called steering offset.

Abbreviation for slow cut solenoid valve
Scuff plate
  1. Any protective plate.
  2. The finishing trim on a door sill
Scuff rib
The raised rib on the sidewall of a tire to protect it from impact with the curb
Sculpture line
Drains from decks to carry off accumulations of rainwater, condensation, or seawater
A process of separation
  1. A small circular or oval opening fitted in decks to provide access.
  2. A British term for Cowl
Scuttle panel
A British term for Cowl
Scuttle section
A subassembly of the body shell that includes the bulkhead, scuttle, and windscreen pillars; it is preassembled in the factory and spot-welded with the other subassemblies to form the body shell
Scuttle shake
A typical vibration exhibited by convertibles on rough roads due to lack of torsional stiffness
Scuttle side panel
A vertical panel at either end of the scuttle
An API designation of oil for gasoline engines for 1968 to 1970 passenger cars and some trucks. This category may also apply to certain 1971 or later models as specified (or recommended) in the owner’s manuals. Oils designed for this service provide more protection against high and low temperature deposits, wear, rust, and corrosion in gasoline engines than the SC oil it replaced. It was replaced, in turn, by SE classified oil. These vehicles can benefit from the modern SM oils.
  1. Abbreviation for Semi-drop center rim.
  2. Abbreviation for Systems Development Charge
Abbreviation for Saab Direct Ignition
Abbreviation for Service District for Lighting
Abbreviation for Sensing Diagnostic Module
  1. Abbreviation for Spark delay valve
  2. Abbreviation for Spark Deceleration Valve
  1. Abbreviation for special edition.
  2. An API designation for gasoline engines in passenger cars and some trucks beginning with 1972 and certain 1971 through 1979 models. Oils designed for this service provide more protection against oil oxidation, high temperature deposits, rust, and corrosion in gasoline engines than oils of SD classification which it replaced. It was replaced, in turn, by SF oil. These vehicles can benefit from the modern SM oils.
A self-propelled sea barge larger than the Lash but using rollers to move aboard the ship
Sea Can
Sea Can
Sea can
A completely enclosed, often water tight container designed to be loaded onto ocean freighters to carry commodities overseas. Also called an ocean container.
Sea chest
An opening for supplying seawater to condensers, pumps, etc. located in the hull below the waterline and having means for the attachment of the associated piping
  1. A flexible ring, disc, or washer that prevents the passage of liquid, air, gas, or dirt.
  2. To prevent the passage of liquid, air, gas, etc. by means of a seal or sealant (e.g., on seams, joints, flanges).
  3. To coat a surface (e.g., when undersealing a car) by closing the pores of the anodic oxide layer in order to increase the resistance to staining and its effectiveness against corrosion
An organic compounds (such as wax, oil, grease) used to protect seams or surfaces.

Seal Bearing
Seal coat
A process of spraying liquid asphalt on the road surface followed by a layer of crushed rock. A seal coat protects the existing road against water damage, adds traction to the road surface and prolongs its life.
Sealed beam
Sealed beam headlight
A headlight Lamp in which the lens, reflector, and Filament are fused together to form a single unit. They are relatively inexpensive, but when one component breaks, the whole unit is replaced. Newer vehicles use the more expensive Composite type with separate Bulb and lens which can be replaced individually in the event of failure. Only a few types of Bulbs are used in the Composite headlight, but the lens differs because it is shaped to the contour of the vehicle.
Sealed beam unit
A headlight that usually contains twin high/low filaments, a reflector, and a lens and is sealed to keep out dirt and moisture. When the headlight fails, you replace the entire unit. Sealed beam units are usually found on older vehicles. Newer ones have halogen headlights.

Sealed bearing
A bearing that has been lubricated at the factory and then sealed, it cannot be lubricated during service. It is sealed to keep out contaminants.
Sealed bottom bracket
A bottom bracket with protective seals to keep water and grime from penetrating to the bearings. Also called cartridge bottom bracket
Sealed pulley
A type of derailleur pulley that has sealed bearings
Sealed unit
Motor compressor assembly in which motor and compressor operate inside sealed housing.

  1. A substance you can add to the liquid in the cooling system to seal leaks. Also called stop leak.
  2. Other kinds of sealing Compounds are used to Coat surfaces before installing hoses or Gaskets. These are effective in preventing leakage but usually make the hose or gasket hard to remove.
  3. An intercoat between the top Coat and the Primer or old Finish, giving better Adhesion.
  4. Any material used to fill cracks and pinholes in a metal surface to be painted, applied before the base coat or as a base coat primer-sealer.
Sealing apparatus
Sealing bath
A hot water bath for the sealing treatment after anodizing
Sealing cell
Sealing compound
Sealing smut
Impurity deposit which forms after the anodized aluminum pieces are immersed in hot water
Sealing strip
Gas seal to the epitrochoidal surface in a rotary engine, with the same function as the piston ring on a conventional piston engine
Seal installer
Seal leak
Escape of oil and/or refrigerant at the junction where a shaft enters a housing.
Seal pliers
Seal ring
Seamed tubing
Tubing made from steel strip stock that is curved until its edges meet, then welded together. Contrast Seamless tubing.
Seamless tubing
Tubing made from solid blocks of steel that are pierced and drawn into tube shape. Contrast Seamed tubing.
Seam sealant
Seam sealing
The sealing of seams, usually using organic compounds, to prevent the penetration of corrosive agents.

Seam sealing cell
A flexible manufacturing cell in which seam sealers are applied
Seasonal energy efficiency ratio
(SEER) A measure of cooling capacity.
  1. A surface upon which another part rests or settles. Example: the valve seat is the matched surface upon which Valve face rests.
  2. Minor wearing of the piston ring surface during initial use. Rings then fit or seat properly against the cylinder wall.
  3. The cushions on which the driver and passengers rest.
  4. A metering control that is regulated by a Needle.
Seat adjuster
A device which operates manually or electronically to move the position of the seat cushion forward or backward. It may tilt the front or back of the seat cushion up or down and may also move the seat back forward or back — even to a reclining position. In some cases the adjuster will allow complete removal of the seat assembly.
Seat belt
Seat beltSeat belt

A passive Restraint system which encircles the hips to prevent the occupant from being ejected from the vehicle. Often the seat belt is part of the shoulder harness. The use of seat belts is mandatory in every province and state in North America and in most every country.

Seat belt anchorage
The point where the end of a seat belt is attached to the body of a vehicle
Seat belt system
Seat belt tensioner
A device that pulls the seatbelt tight in the event of a collision, taking up extra slack and reducing the force with which the occupant’s body hits the belt. It is sometimes referred to as a pretensioner, though this implies that it deploys when a crash is imminent, which is misleading. Tensioners are generally tied into the same sensors that trigger the airbags and deploy at the moment of collision.
Seat belt warning light
A light on the instrument panel which illuminates or flashes if the seat belts are not fastened.
Seat cluster
On a bicycle, the conjunction of Top tube, Seat tube, and Seatstays near the top of the seat.
Seat cover clip
Seat cover clipSeat cover clip

A spring steel clip used to secure the front seat sideshield and front seat back panel.

Seat covers
Trucker slang for attractive women in vehicles as in ‘Look at the seatcovers in that westbound rollerskate.’
Seat cover S-hook
Seat cover S-hookSeat cover S-hook

A steel hook used to secure the seat cover to the frame.

Seat cushion
The part of the seat upon which one sits or leans against.
Seat cutter
Seat diameter
Seat face
Seat grinding
Seating buck
A temporary adjustable seat in a vehicle used in the design stage to determine the best shape and location.
Seating capacity
The number of people for which a vehicle is designed to carry.
Seat insert
Seat-integrated belt system
A seat belt with all belt elements and deflection points integrated in the seat; this improves occupant restraint in every seating position, but particularly sturdy seats and floorpans are required
Seat-integrated seat belt system
Seat mat
Seat pan
Seat panel
On a bicycle, the part to which the Saddle clamps and which runs down inside the Seat tube.
Seatpost binder bolt
A bolt or quick release at the top of the seat tube used to hold the seatpost in place.
Seat rail
Tracks on which the front seat frame is mounted to provide fore and aft seat adjustment
Seat rail console
A mounting panel for the seat rails, spot-welded to the floorpan; the front consoles are usually somewhat higher than the rear ones to produce the desired angle of the seating surface
Seat ring
Sea trials
A series of test runs done at sea to determine whether the ship has met the specifications of design, modification, or repair
Seat runner
Tracks on which the front seat frame is mounted to provide fore and aft seat adjustment
Seat skin
The covering (usually leather or vinyl) of the saddle on a motorcycle or bicycle.
On a bicycle, one of the two parallel tubes that run from the top of the Seat tube back to the rear dropout.
On a bicycle, the two parallel tubes that run from the top of the Seat tube back to the rear dropouts.
Seat taper
Seat tube
On a bicycle, the tube that runs from just below the Saddle down to the bottom bracket.
Seat well
A sheet metal panel to cover up the area below the car seats, especially below the rear seat bench
Sea worthiness
The condition of a vessel with regard to materials, construction, equipment, crew, and outfit which is considered safe for the trade in which it is employed
Seaworthiness certificate
A certificate issued by a classification society surveyor allowing a vessel with a mishap affecting its seaworthiness to proceed to another port where permanent repairs can be carried out.
The high voltage side of the ignition system, usually above 20,000 volts. The secondary includes the ignition coil, coil wire, distributor cap and rotor, spark plug wires, and spark plug

Secondary air
  1. In some exhaust emission control systems, e.g., thermal reactor or two-bed converter, secondary (outside) air is added to the exhaust to ensure sufficient supply of oxygen to promote oxidation of HC and CO, thus converting these pollutants into harmless water vapor and carbon dioxide.
  2. Air externally supplied to the flame at the point of combustion.
Secondary air anti-backfire valve
A check valve that prevents exhaust system backfires from entering the secondary air system.
Secondary air bypass valve
An electronically controlled solenoid/vacuum valve that directs secondary air from the air pump to the atmosphere or to the secondary air switching valve.
Secondary air pulse valve
A valve activated by exhaust that uses the negative pressure pulses in the exhaust to draw secondary air into the exhaust system.
Secondary air switching valve
An electronically controlled solenoid/vacuum valve that directs secondary air from the pump to either the catalytic converter or the exhaust ports of the engine.
Secondary battery
Secondary brake shoe
Secondary braking system
(HGV) A spring brake system which exerts force when air pressure is released
Secondary cell
Secondary circuit
  1. The high voltage part of the ignition system.
  2. The circuit which comprises the secondary winding of the ignition coil, the distributor, and the spark plugs
Secondary compression
A term that is used in two-stroke engines. Primary compression takes place in the crankcase and is then pushed up into the combustion chamber where secondary compression takes place as the piston squeezes the mixture. If the crankcase seals are poor, Primary compression will be reduced resulting in reduced secondary compression so that it may be difficult to start the engine.
Secondary controls
Devices in a vehicle that do not direct its movement or braking but control how the driver sees out of the vehicle and how the vehicle is seen; examples are de-misters, windscreen wipers, washers and hazard lights
Secondary damage
Secondary failure
The failure which occurs as a result of a primary failure (e.g., the primary failure is a flat tire caused by a nail hole; but as the tire continues to run flat, the secondary failure may be a tire roll-off where the tire comes off the rim). A good mechanic will search for the primary failure so that a secondary failure will not be repeated.
Secondary ignition
The high-voltage part of the ignition circuit, such as part of the ignition coil wiring, spark plugs, spark plug wires, distributor cap, and rotor. Compare Primary ignition
Secondary key
A key which operates only the locks needed for valet parking, i.e., door locks, ignition switch, and steering column lock; does not allow access to trunk, glove box, etc.
Secondary operations
  1. Less important than the major steps of heading or cold forming fasteners, secondary operations include grinding, polishing, drilling.
  2. Operations which include punching, shaving, trimming, drilling, sawing, milling, pointing, tapping and polishing, etc., are generally called secondary.
Secondary pattern
An oscilloscope pattern of the secondary circuit
Secondary piston
  1. In a dual or tandem master cylinder, it is the piston which is normally pushed forward by fluid trapped between it and the primary piston.
  2. In a tandem master cylinder, a floating piston which isolates the two braking circuits from each other and actuates the secondary circuit
Secondary pump
An oil pump driven via the gearbox output shaft. Compare Primary pump
Secondary refrigerating system
Refrigerating system in which the condenser is cooled by a different evaporator from the primary refrigerating system.
Secondary roads
Secondary seal
A secondary piston seal in a tandem master cylinder
Secondary shoe
  1. The shoe in a duo-servo drum brake assembly that is acted upon by the primary shoe. It provides more stopping power than the primary shoe (about 70%).
  2. The rear shoe in a drum brake; often has longer lining than the other shoe.
Secondary visor
In a dual visor system, the main visor is moved to the side and the secondary visor is flipped down, thus shielding the driver from the sun from both the front and side
Secondary winding
  1. An inner winding of the ignition coil; typically 20,000 to 30,000 turns of very fine wire. The opposite is primary winding
  2. The secondary winding of an electric motor is a winding that is not connected to the power source but carries current induced in it through its magnetic linkage with the primary winding
Secondary wire
Secondary wires
The high voltage wire from the Coil to the distributor tower and from the tower to the spark plugs.
Second gear
A middle gear which has a faster ratio than low gear, but slower than high gear. It is used for climbing or descending steep hills
Second law of thermodynamics
Heat will flow only from material at higher temperature to material at lower temperature.
Second rule
Section Construction
Section damage
Section height
The vertical measurement from the bead seat of a tire to the top of the crown when it is mounted, inflated and not under load. (Overall diameter less nominal rim diameter, divided by two.)
Section repair
  1. Reinforcement made to the Casing when an injury has extended through the tread or sidewall of a tire. The damaged cord is removed and a new cord is replaced in the form of a repair unit or patch.
  2. A major repair in the sidewall or tread of a tire. This repair unit must have cord material for reinforcement, made specifically for the type of tire — bias-ply or radial.
  3. An effective and economical repair method where extensive damage is confined to a specific section of the body shell and an undamaged section is taken from a vehicle which has been written off
Section width
The measurement across the tire width at the widest point when mounted and inflated (not under load), excluding any decorative moldings.
Sector shaft
Security system

The term sedan originally described a conveyance seen only in movies today — a wheelless vehicle for one person, carried on poles by two men, one ahead and one behind. Automakers borrowed the word and applied it to cars with an enclosed four-door body type, permanent back panels, and top with full-width cross seats front and rear, and passenger capacity from five to seven depending on wheelbase. Longer-wheelbase models accept extra passengers in fold-down auxiliary seats. Sedans usually have quarter windows in the rear quarter in addition to windows in all four doors. trunk racks often were standard offerings. Called saloon in U.K. According to Car and Driver, the term ‘sedan’ refers to a fixed-roof car with at least four doors or any fixed-roof two-door car with at least 33 cubic feet (934 litres) of rear interior volume, according to measurements based on SAE standard J1100.

An early body style in which the top extended for a quarter of a circle and covered only the passengers in the rear seats.
A two-door sedan having a slanted back with the rear window and trunk along one unbroken curve. This name for the early streamlined design is most often used for Buick and Cadillac models, but similar designs of other makes are known by various names such as ‘Aero’ (Chevrolet), ‘Jetback,’ ‘Streamliner’ (Pontiac), ‘Torpedo,’ and simply ‘fastback.’.
A two-door sedan having a slanted back with the rear window and trunk along one unbroken curve. This name for the early streamlined design is most often used for Buick and Cadillac models, but similar designs of other makes are known by various names such as ‘Aero’ (Chevrolet), ‘Jetback,’ ‘Streamliner’ (Pontiac), ‘Torpedo,’ and simply ‘fastback.’.
An accumulation of matter which settles to the bottom of a liquid.
Seebeck effect
When two different adjacent metals are heated, an electric current is generated between the metals.
A paint fault where a uniform distribution of small particles of regular size and pattern exist in a paint film. It is caused by contamination of the paint and poor filtration of the air lines. It is not to be confused with dirt contamination which is caused by dust settling on the painted surface before it has dried
A feature of a car stereo where the radio will find a requested station.
Abbreviation for Seasonal energy efficiency ratio.
Abbreviation for Sequential electronic fuel injection
Segregated cycle route
(SCR) A pathway dedicated exclusively for bicycle and not for pedestrians or other vehicles. Unlike Multiple-use paths.
  1. The condition when two items bond together so that they cannot be removed easily.
  2. The condition when a piston bonds itself to the sides of the cylinder wall because of the lack of lubricant or overheating.

Selectable four-wheel drive
A four-wheeled vehicle which proceeds normally in two-wheel drive but on which, by means of a lever control, four-wheel drive may be selected. It is important to remember that such vehicles in four-wheel drive do not have the benefit of a center differential
Selected Copper
Selective absorber surface
  1. Surface used to increase the temperature of a solar collector.
  2. A solar absorber surface that has high absorbtance at wavelengths corresponding to that of the solar spectrum and low emittance in the infrared range.
Selective Catalytic Reduction
(SCR) Term frequently used as a synonym for catalytic reduction of NOx in diesel exhaust or flue gases by nitrogen containing compounds, such as ammonia or urea. Such SCR systems are commercially available for stationary applications and are being developed for mobile diesel engines. Since selective catalytic reduction is a generic term which also applies to other reactions, its use may lead to confusion in some situations.
Selective corrosion
The corrosion of alloys where the components react in proportions differing from their proportions in the alloys
Selective Oxidation
Selective transmission
The conventional manual transmission of today in which any gear may be selected at will as opposed to the very early Progressive transmission in which the gears had to be selected in order.
Select-low principle
  1. The method by which the rear brake application of an ABS brake system is monitored and controlled, based on the rear wheel with the least amount of traction
  2. The controlling principle for rear-wheel anti-lock systems which states that pressure to both wheels shall be limited to the level required by the wheel with the least traction.
Selector fork
Selector ForkSelector Fork

A part of the selector mechanism of a manual gearbox, shaped like a two-pronged fork, which fits into the groove round a coupling sleeve and moves a sliding pinion forward or back along a selector rod

Selector indicator
Selector lever
An automatic transmission lever which permits the driver to adapt the gearchanging processes to particular road or driving conditions (slippery road surface, hilly terrain, towing) by choosing one of the drive ranges. Reverse, neutral, and parking lock are also selected by means of the selector lever
Selector lever lock
A device which locks the selector lever in Neutral or Park unless the driver depresses the brake pedal
Selector rod
A rod running the length of the transmission, along which the selector fork travels
Select valve
A mechanism that adjusts itself to compensate for wear or to maintain a certain distance or heat level
Self-adjusting drum brakes
A brake that automatically maintains the correct clearance between the lining and the drum.
Self-aligning torque
A torque which is created by the tire when the vehicle corners. The force created at the tire Patch acts toward the rear of the actual center of the wheel. This action is called pneumatic trail. It has the same effect as positive Caster and can be increased by increasing the positive Caster. Thus the Trail distance (distance from the point at which the cornering force acts to the center of the wheel or Steering axis) is a moment arm that results in a torque that tends to decrease the existing Slip angle and force the wheel back to the straight-ahead position. This self-aligning torque is transmitted through the steering mechanism to the steering wheel and can be felt as steering effort or Road feel.
Self-cancelling indicator
All modern signal light switches (direction indicators) switch off automatically when the steering wheel is returned to the straight-ahead position
The forces in a steering system that set the front wheels straight when the driver’s grip on the steering wheel is released after cornering
Self-centering effect
The forces in a steering system that set the front wheels straight when the driver’s grip on the steering wheel is released after cornering
The ability of a spark plug to burn off the deposits of carbon and oil which build up due to tracking across the tip
Self-cleaning limit
The lower limit of the self-cleaning temperature, generally about 500°C
Self-cleaning tread
A tread pattern with tapered grooves and ribs, bars, etc., arranged in a manner that resists packing loose materials, (mud, etc.) in the grooves.
Having all essential working parts, except energy and control connections, so contained in a case or framework that they do not depend on equipment or fastenings outside of the machine.
A test function in electronic engine management systems with a test program monitoring input and output signals, detecting errors and storing them permanently in a fault memory
Self-diagnostic code
The ECM can detect malfunctions in the CCC systems. If a malfunction occurs, the ECM turns on the check engine light. A diagnostic code can be obtained from the ECM through the check engine light. This code will indicate the area of the malfunction
A brake shoe that is forced into the drum by the movement of the drum. A self-energizing shoe is mounted so its friction surface leads or is ahead of its pivot point.

Self-energizing action
The action of a rotating brake drum that increases the application pressure of the brake shoe(s).
Self-energizing brake
Self-energizing brake shoe
A brake shoe (sometimes both shoes) that when applied develops a wedging action that actually assists or boosts the braking force applied by the wheel cylinder.

Self-grip pliers
The ignition of the air/fuel mixture in a diesel engine caused by high pressure and temperature. Different from a Spark ignition
Magnetic field induced in conductor carrying the current.
This occurs when the current in an inductive circuit changes and the magnetic field cuts the conductors; this induced electromotive force opposes the change in current, restricting it if the current is increasing and enhancing it if the current is decreasing
Self-induction back-voltage
Back-voltage produced by self-induction. This induced electromotive force opposes the change in current, restricting it if the current is increasing and enhancing it if the current is decreasing.
Self-leveling shock absorber
Self-leveling strut
A suspension strut incorporating a shock absorber with a rubber boot filled with compressed air, serving as an auxiliary pneumatic spring
Self-leveling suspension
Where binding action is self-induced on the body of the bolt, screw or nut to keep it rigid and prevent movement and vibration.
Self-locking nut
A nut with a nylon insert that binds on the thread and resists vibration
Self-operating clutch
The ability of a car to park automatically, without any input from the driver; introduced by the VW Futura in 1991
Self-parking wiper
A windshield wiper that automatically returns to the (horizontal) park position when switched off
Self-priming pump
A pump which is able to evacuate and prime the suction pipe
Self-regulating sheathed-type glow plug
Originally a sheathed-type glow plug with a self-regulating heating coil, now with a heating and regulating coil

Self-sustaining ship
A containership fitted with her own crane for loading and discharging containers
Self-tapping screw
A screw which cuts its own threads as it is inserted into the hole
Self test
A part of functional diagnostic test procedure that verifies operation of sensors and actuators, detects hard faults, and stores information for later retrieval
Self-trimming ship
A ship whose cargo holds are shaped so that the cargo levels by itself.
A bulk carrier which is equipped with cargo unloading gear
Vulcanization at room temperature or above, activated by chemical agents without the application of heat from an outside source.
A preassembled fastener, consisting of any type of screw or bolt, furnished with a toothed washer

Abbreviation for Specialty Equipment Market Association, the aftermarket and Reproduction vehicle parts organization.
Semaphore indicator
Semaphore indicatorSemaphore indicator

A signal light indicator used before flashers were introduced (such as on the Austin and Flying Standard), consisting of a lighted arrow that popped out from the side of the car (usually the B-post) when the turn signal switch was actuated. Also called trafficator

Semi-active suspension
A suspension whose characteristics can be tuned to driving conditions, such as by hydraulic adjustment of spring supports plus electronic correction of the damping rate
Semi-automatic frost control
Control which starts defrosting part of a cycle manually and then returns system to normal operation automatically.
Semi-automatic transmission
A transmission in which the clutch is disengaged and re-engaged automatically when the driver actuates the gear lever
Semi-Automatic valve
A valve that is opened manually and closed automatically, or vice versa.
Semi-centrifugal release finger
  1. A solid material such as silicon that has a resistivity midway between that of a conductor and a resistor, with properties of both a conductor and an insulator; used as substrates for semiconductor devices such as diodes, transistors, and integrated circuits
  2. Any material that has a limited capacity for conducting an electric current. Certain semiconductors, including silicon, gallium arsenide, copper indium diselenide, and cadmium telluride, are uniquely suited to the photovoltaic conversion process.
Semiconductor ignition system
An ignition system that uses semiconductors for the switching operations
A semi-diesel engine operates on comparatively high compression and uses solid injection of fuel, however, it does use an electrical ignition system rather than depend solely upon heat generated by compression to furnish ignition
Semi-drop center rim
(SDC) A wheel rim having a demountable flange, for use on light commercial application. A slight depression in the center of the rim facilitates tire mounting and removal.
Semi-drop center rim taper
A wheel rim where both bead seats are tapered 5°.
Semi-drying oil
Those oils which are only partially hardened or are changed into a sticky mass when exposed to air and sunlight. The chief semi-drying oils used in paint, varnish, and lacquers are soybean oil, corn oil, and cotton-seed oil.
Semi-elliptic leaf spring
Semi-elliptic spring
Semi-elliptic springs
Semi-elliptic springsSemi-elliptic springs

A type of Leaf spring that takes its name from the shape which is part of an ellipse.

Semi-Finished Hexagon Bolts
Bolts with standard sizes ranging from 1/4′ through 4′. Class 2A tolerance. The bearing surface is washer faced.
Semi-floating axle
Type of axle commonly used in modern vehicles. The outer end of the axle shaft does two things (1) it supports the weight of the vehicle and (2) it is the means of propulsion. The inner end of the axle shaft which is Splined, floats in the Differential gear. In this design a single bearing is placed between the axle shaft and the axle bearing; to remove the axle the wheel must first be removed.
Semihermetic compressor
Hermetic compressor with service valves.
Semi-independent suspension
A rear axle design with a torsionally flexible crossmember, the wheels being located on trailing links
Semi-metallic lining
  1. Brake lining incorporating a high-percentage of metal in its composition.
  2. A heavy-duty lining molded from iron powder, steel fibers, and organic binders works especially well at high temperatures.
Semi-race cam
A type of camshaft for race car engines which increases lift of valve, speed of valve opening and closing, length of time valve is held open, etc. Also called Full cam, Three-quarter cam, or Race cam, depending upon design
Semislick tire
A type of mountain bicycle tire with limited tread; popular for not-too-technical courses because it rolls faster than a knobby tire

  1. A type of trailer that has wheels only at the rear, the front is supported by the towing vehicle or a dolly
  2. The front portion of a semitrailer rests on the back of a tractor. The semitrailer is coupled to the tractor by the fifth wheel on the tractor and the kingpin on the trailer. A semitrailer has no front axle and cannot stand without support. Semitrailers are pulled by tractors only. A trailer whose front half rests on the back of a tractor, coupled to the tractor by a fifth wheel.

Semi-trailing arm
A type of Independent rear suspension where the pivot axes are usually at about 25 degrees to a line running straight across the car. This arrangement gives rear-wheel Camber somewhere between that of a pure Trailing arm (which has no Camber change relative to the body) and a Swing axle (which has large Camber change).
Semi-trailing arm suspension
Semi-trailing link
An arm of a coil spring, independent rear suspension system which pivots at an angle to the centerline of the vehicle, thus imparting negative camber with increase in load. Also called Semi-trailing arm
Sems screw
A machine screw and free-spinning lock-washer manufactured as one assembly. Steel SEMS are available with the following types of washers: internal tooth, external tooth, split-lock and square-cone. Stainless SEMS are offered with external tooth lock washers.
A sensor unit conveying information about an engine to a gauge, warning light, or other component.

Sending unit
A device used for transmitting a signal to a gauge.
Send test
Sendzimir process
A continuous strip galvanizing process, named after its inventor. The strip is wound from a coil while the oil or grease adhering to it is removed by oxidation. It is then annealed, and the oxides are reduced by ammonia, after which it is cooled to 500°C and immersed in a zinc bath, which is kept molten at about 45O°C by the heat from the steel strip. On leaving the bath, the strip is cut and coiled
Senna, Ayrton
Ayrton Senna (full name Ayrton Senna Da Silva) of Brazil was, without question, the greatest race car driver in history. He was the embodiment of the professional race car driver. From his first appearance in a Grand Prix event in 1984, the racing world was on notice. The man was on a single-minded mission to win a World Championship title. No driver ever pursued this goal with such determination. Senna won his first title in 1988 and then again, two more times, in 1990 and 1992. He sat on the pole for more than 55% of all races he entered. Ayrton Senna was killed during the opening laps of the 1994 Grand Prix of San Marino at the Circuit dino Ferrari near the town of Imola in Italy. His death was mourned the world over. Both Brazil and Japan took national holidays to mourn his passing. At the time of his death, Ayrton Senna was so significant to Brazil as a hero and source of income, he was responsible for nearly 20% of that country’s gross national product. His body lay in state in the National Assembly before being buried with full state rights. At the time of this writing, rather pointless charges of manslaughter have been brought against the team Senna drove for at the time of his death. Frank Williams (the team owner), Adrian Newey (team Chief Designer) and Patrick Head (team Technical Manager) all face charges.
Sensible heat
Heat which causes a change in temperature of a substance.
Sensing device
Sensing Line
Sensing Proportioning Valve
Sensing Switch
Sensitive Adhesive
Sensitive bulb
Part of sealed fluid device which reacts to temperature. Used to measure tem or to control a mechanism.
Sensitive limited slip differential
The percent of speed change required to produce a corrective movement of the governor or other speed control mechanism of an engine.

  1. An electronic detection device that receives and reacts to a signal, such as a change in voltage, temperature or pressure.
  2. Material or device which goes through physical change or electronic characteristic change as surrounding conditions change.
  3. Any device that receives and reacts to a signal, such as of a change in voltage, temperature, or pressure. Sends an input signal to a computer.
Sensor flap
A part of an airflow detection device which serves as a measure for the induced air volume; a potentiometer converts sensor flap movement into changes in electrical voltage, a form in which these signals can be evaluated by the fuel injection control unit
Sensor plate
  1. A plate in the mixture control unit of a CIS, attached to a lever that operates the control plunger in the fuel distributor; the sensor plate position is governed by the amount of air admitted to the engine via the throttle valve and auxiliary air regulator
  2. A round plate bolted to the air flow sensor lever which floats in the stream of intake air on the CIS type systems
Sensor system
Sensor system thermo-switch
SentraClick image for books on

A model of automobile manufactured by Nissan in Japan

Abbreviation for Special Equipment Option
Separate-application adhesive
An adhesive consisting of two parts; one part being applied to one face and the other part to the other face and the two faces brought together to form a joint
Separate chassis
The traditional body and frame design before the introduction of unitary construction; the body was lowered onto the chassis and bolted to it
Separate lubrication
An engine lubrication principle where the oil is no longer mixed with the fuel, but is fed by a metering pump from a separate oil tank to the engine components to be lubricated
  1. The parting of retread rubber from the buffed Casing or the parting or debonding of any adjacent parts of the tire (ply to ply, ply to rubber, etc.), usually due to excessive heat.
  2. After long storage, liquid ingredients of paints and fillers may separate in the can on top of the material; in most cases, this can be overcome by stirring the contents of the can thoroughly before use.
Separation solid tire
Rubber pulling away from steel bands.
Device to separate one substance from another.

Separator assembly-fuel vacuum
(SA-FV) fuel vacuum separator FVS
Separator, oil
Device to separate refrigerant oil from refrigerant gas and return the oil to compressor crankcase.
Separator plate
A solid piece of electrically conductive material (usually a metal or graphite) that is inserted between cells in a stack.

  1. Generally, anything that physically separates one part from another.
  2. The wood, rubber, or plastic sheets or plates inserted between the positive and negative plates in a battery to prevent contact.
  3. A filter or trap.
The order in which events take place.

Sequence controls
Group of devices which act in series (one after another) or in time order.
Sequence test
Sequential electronic fuel injection
(SEFI) a computer controlled fuel system that distributes fuel through an injector located in each intake port of the engine. Each injector is fired separately and has individual circuits. Also called Sequential fuel injection (SFI)
Sequential fuel injection
(SFI) A computer controlled fuel injection system in which bursts of gasoline are sprayed into the intake ports by injectors at timed intervals. Each injector is fired separately and has individual circuits. Also called Timed fuel injection or Sequential electronic fuel injection (SEFI)
Sequential spark
Serial number
The individual, consecutive numbering of a product during production. It may be a combination of letters and numbers.

  1. A particular type of an automobile make and model. For instance, in 1952 Cadillac fielded three series a 62 (with a 126 inch wheelbase); a 60 (with a 130 inch wheelbase); and a 75 (with a 147 inch wheelbase).
  2. The alignment of electrical components.
  3. A numerical representation of a tire’s aspect ratio. A 50-series tire has an aspect ratio of 0.50.
  4. A method of connecting several parts in a row so that one feeds into the next.
Series circuit
  1. A circuit with two or more resistance units so wired that the current must pass through one unit before reaching the other. In contrast with Parallel circuit.
  2. Electrical wiring; electrical path (circuit) in which electricity to operate second lamp or device must pass through first; current flow travels, in turn. through all devices connected together.
Series connection
A way of joining photovoltaic cells or batteries by connecting positive leads to negative leads to increase the voltage. Two twelve-volt batteries connected in series results in an output of 24 volts. Contrast Parallel connection where positive is connected to positive and negative to negative resulting in a stronger 12 volts (i.e., more amperage).
Series custom
Custom bodies made up in small batches, usually ranging from five to 25. Also called ‘semi custom.’
Series-parallel circuit
A circuit of three or more resistance units in which a series and a Parallel circuit are combined.
Series resistance
Parasitic resistance to current flow in a cell due to mechanisms such as resistance from the bulk of the semiconductor material, metallic contacts, and interconnections.
Serpentine belt
A Poly-v-belt which wraps around several pulleys and idlers
Serrated shaft
A shaft with V-shaped grooves
A series of teeth on an edge (as on a saw)
  1. Periodic maintenance usually carried out by a garage; includes changing the oil and oil filter, checking the brakes, tires, ignition (usually changing the spark plugs), electrical, fuel and cooling systems, and taking the vehicle on a test run to check the steering, suspension, and transmission systems as well as the performance of the engine and brakes.
  2. To carry out a service on a vehicle.
Serviceable hermetic
Hermetic unit housing containing motor and compressor assembly by use of bolts or cap screws.
Service Bench
Service brake
  1. A foot-operated brake used for retarding, stopping, and controlling the vehicle during normal driving conditions
  2. The primary brake system controlled by the brake pedal, operates the friction assemblies at all four wheels, and slows or stops the car in normal driving.
Service brake valve
A foot-operated unit which is used for graduated control of all the brakes in the service brake system.
Service codes
A series of two digit numbers that represent results of a self test

Service Consultant
At many dealerships, the person responsible for receiving cars brought to the service department, in order to estimate the nature and cost of repairs and when the work will be completed. Also called Service writer
Service Council
Service Cylinder
Service factor

  1. A measure of the overload capacity designed into an electric motor. A 1.15 SF means the motor can deliver 15 percent more than the rated hp without injurious overheating.
  2. A multiplier that, when applied to the rated power, indicates a permissible power loading that may be carried under the conditions specified for service factor.
Service history
Service hose
Specially manufactured hose designed to withstand the operating pressures of air conditioner system and equipped with threaded fittings that can be attached to service valves, manifold gauge sets, vacuum pumps, refrigerant containers, etc.
Service interval
The time or mileage between services (e.g., 12 months or 10,000 miles, whichever should come first)
Service life
The length of time a component or system will remain reliable and safe
Service manifold
Chamber equipped with gauges and manual valves, used by service technicians to service refrigerating systems.
Service manual
A handbook published by a vehicle manufacturer or a specialized publishing company that contains instructions and Specifications for the maintenance and repair of a specific car. It may include Wiring diagrams and Troubleshooting guides. Most service manuals deal with only one make, model, or year, and nearly all are intended for professionals or the very experienced amateur.
Service port
A fitting, on stem-type service valves and some control devices, to which manifold gauge set service hoses can be connected
Service station
Outlets which sell gasoline and are operated by the major oil companies.
Service valve
  1. The high or low side service valves.
  2. Manually operated valve mounted on refrigerating systems used for service operation.
  3. Device used to check pressures, service, and charge refrigerating systems.
Service writer
At many dealerships, the person responsible for writing repair orders (work orders) is the service writer. He communicates to the mechanic and service manager the problems in your vehicle that you have outlined. He also Estimates the nature and cost of repairs and gives you an idea when the work will be finished. Also called Service consultant
To carry out a Service
  1. A servo motor supplies power to a servo-mechanism. A servo-mechanism is a low-power device (electrical, hydraulic, or pneumatic) used to put in operation and control a more complex or powerful mechanism.
  2. An oil operated device used to push or pull another part, such as tightening the transmission brake bands.
  3. Any system used to assist a mechanism to operate with greater force than that initially applied to it.
  4. Abbreviation for Servomechanism
Servo action
Describes how one brake shoe adds to the application force of the other.
Servo action brake
Servo action brakes
Brakes so constructed as to have one end of the primary shoe bearing against the end of the secondary shoe. When the brakes are applied, the primary shoe attempts to move in the direction of the rotating drum and in so doing applies force to the secondary shoe. This action, called servo action, makes less brake pedal pressure necessary and is widely used in brake construction.
Servo-action drum brake
Servo brake
  1. A drum brake in which the shoes are arranged so that one shoe helps to apply the other, to create a self-energizing effect in both shoes
  2. A drum brake in which brake shoes are linked, such that the braking force of one shoe amplifies the input of the other shoe(s).
A device that provides power assistance to operate a control (e.g., a brake or clutch)
Servo motor
  1. A small electric motor that supplies power to a Servomechanism
  2. A calibrated vacuum or electrical motor used to position valves or doors in an automotive air conditioning system.
Servos apply certain mechanical functions. For instance, if first gear is actuated by the application of a band, the servo is what applies that band. The servo is nothing more than a piston that is connected to a mechanical linkage, moved by hydraulic pressure. When the need for a certain application arises, oil pressure moves the servo and the servo makes the application.
Abbreviation for Service Engine Soon obsolete term replaced by MIL
  1. To adjust (e.g., a screw) to a standard.
  2. To allow to harden (e.g., body filler, glue, etc.)
Setback Axle
The front steering axle moved rearward from the generally accepted standard position. Advantages Shorter turning radius and more of a vehicle’s weight shifted to the front axle.
Set screw
  1. A fully threaded bolt with a parallel shaft. It is used to secure metal parts together (such as a hub or wheel to a shaft); can have a variety of heads, the most common being hexagonal, round or countersunk
  2. An externally threaded fastener with or without a head and having a formed point, designed to prevent relative movement of parts when screwed through one part upon or into another part.
Set Screw Points
A screw with various type points, cup, cone, flat, oval, half dog, full dog, hanger or knurled, used to hold or ‘set’ a collar on a shaft or hold pieces of this kind against movement. Screws are usually short, threaded entire length with the various type points for different applications against this movement.
Setter hammer
  1. Adjustment.
  2. Hardening.
Setting time
The time required for a adhesive, sealer or coating to approach maximum strength and firmness as it dries or sets
To sink to the bottom (of a liquid). The weight of the pigments in a paint varies greatly depending on their color. Heavy pigments give color, opacity, and specific properties to the paint. Some pigments weigh seven or eight times as much as the liquid part of the paint and because of this, they tend to settle to the bottom of the container
The Pigment in the paint collecting at the bottom of the spray gun container.
  1. Premature vulcanization of a rubber compound during processing or storage.
  2. The action of a gel-like substance which goes from a liquid to a rubbery solid or when a paste turns solid.
Seventy-five (Cadillac)
A 1936-76 Cadillac vehicle brand of which the Sedan/Limo for 1946-70 are milestone cars. Also see history of Cadillac.
SevilleClick image for books on

A model of automobile manufactured by the Cadillac division of General Motors from 1975 to 2004. The name was also used on some Eldorados as Eldorado Seville from 1956 to 1960.

Sewage gas
A gas produced from sewage sludge as it decomposes aat a sewage disposal plant.
Sew up tire
Sew-up tire
A bicycle tire with an Inner tube stitched inside the casing; also known as a tubular.
  1. Abbreviation for Service factor
  2. An API classification for oil in gasoline engines in passenger cars and some trucks beginning with 1980 through 1989 models. Oils developed for this service provide increased oxidation stability and improved antiwear performance, and better protection against engine deposits, rust, and corrosion than the SE classified oil it replaced. It was replaced, in turn, by SG classified oil. These vehicles can benefit from the modern SM oils.
Abbreviation for sulfur hexafluoride
Abbreviation for Specific fuel consumption
Abbreviation for Sequential fuel injection


An API designation for oil used in gasoline engines in 1989-92 passenger cars, vans, and light trucks. Category SG oils also include the performance properties of API Service Category CC. (Certain manufacturers of gasoline engines require oils that also meet the higher diesel engine Category CD.) Oils developed for this service SG provide improved control of engine deposits, oil oxidation, and engine wear relative to oils developed for previous categories. These oils also provide protection against rust and corrosion. It replaces SF class oil and was replaced by SH classified oil. These vehicles can benefit from the modern SM oils.

SHAPI SH category

An API designation for oil used in gasoline engines in passenger cars, vans, and light trucks of 1993-96. Engine oils developed for this category provide performance exceeding the minimum requirements for API Service Category SG, which it replaced, in the areas of deposit control, oil oxidation, wear, rust, and corrosion. Oils meeting API SH requirements have been tested according to the American Chemistry Council (ACC) Product Approval Code of Practice and may use the API Base Oil Interchange and Viscosity Grade Engine Testing Guidelines. Effective August 1, 1997, API SH cannot be used except with API CF, CF-2, CF-4, or CG-4 when displayed in the API service symbol, and the C category must appear first. This SH oil was replaced by the SJ classification. These vehicles can benefit from the modern SM oils.


A swinging support which is used to attach the ends of a Leaf spring to the frame of the vehicle. The shackle is needed to take care of the changes in length of the spring as it moves up and down. Also called Spring Shackle or Swinging Shackle.

A Sunvisor.
Shaded-pole motor
Small ac motor designed to start under light loads.
A long smooth-surfaced bar of metal with a circular (round) cross section.

Shaft alley
A long groove (or hole) along which (or through which) a rod is designed to go.
Shaft distributor
A distributor whose drive shaft projects into the engine; the shaft is driven via a gearing system or a coupling
Shaft drive
A description of a motorcycle which uses a drive shaft between the transmission and the rear wheel instead of a chain.
Shaft-drive system
System that transmits power to the rear wheel via a drive shaft.
Shaft jacking
Shaky or bumpy motion created by the impact of acceleration and then fed back into the bike’s frame.
Shaft seal
  1. A Seal used to do two things to prevent fluid from leaking out between a stationary part and a rotating shaft and to prevent foreign matter from getting in.
  2. Device used to prevent leakage between shaft and housing.
Shaft sleeve
A sleeve which protects a shaft from erosion, corrosion, and wear at shaft seals
Shaft-to-cage coupling
A viscous coupling design in which the outer disc carrier is connected to the differential cage, while the inner disc carrier is connected to an axle shaft
Shaft-to-shaft coupling
A viscous coupling design in which the outer disc carrier is connected to the left-hand axle shaft and the inner disc carrier to the right-hand axle shaft
Shake the leaves
Trucker slang for see what’s ahead as in ‘I guess it’s my turn to shake the leaves.’
Shakey town
Trucker slang for Los Angeles, California as in ‘I’m on a mission to shakey town.’
Shallow angle
An angle that positions the bicycle frame tubes relatively farther from vertical and closer to horizontal than do Steep angles.
Shallow angles
Angles that position bicycle frame tubes relatively farther from vertical and closer to horizontal than do Steep angles.
Shallow pits
Corrosion in the form of pits whose diameter is substantially larger than their depth
Shammy leather

  1. The part of a bolt between the head and the thread.
  2. The part of a bit which is held in the drill.
Shank length
The distance from the last full form thread of a bolt to the bearing face
Shape template
A guide or a pattern used in manufacturing items
The preliminary sanding or forming of the filled surface with coarse grit paper or a body file to establish the approximate body contours; this step is followed by final sanding
Shared component
A part or component which is identical in various models of a car family, such as those used on a sedan and its convertible derivative; typical shared components are body panels, suspension components, brakes, wheels
Shark tooth
Shark tooth pliers
Sharpe Wire Gauge
  1. Removal of some chrome or decorative part.
  2. Removal of metal from the contact surface of the cylinder head or the Block.
A modification of the body of a car to remove all chrome parts at the front or rear end to achieve smooth contours highlighted only by the paint and the body modifications; in most cases, only a side chrome strip is retained. Also called nosing or decking
  1. To distort or fracture as a result of excess torsion or transverse load.
  2. To cut off an object (e.g., metal bar, metal sheet) between two blades.
Shear bolt
A bolt which is used to connect two components. When torque is applied to remove the bolt, the head is designed to shear off. In this way, the disassembly of the component becomes more difficult. It is used to discourage unauthorized disassembly.
Shear Nut
A fine threaded thin castle or slotted nut
Shear pin
A cylinder shaped item that is made of a substance which will break when subject to great pressure. In this way the main component which is more expensive will not be damaged. The pin can usually be easily replace.


A scissors-like tool for heavy-duty cutting. Also called Snips.

Shear Strength
  1. The stress required to produce a fracture when impressed vertically upon the cross-section of a material. Expressed in psi.
  2. The resistance to breaking caused by the push or pull action against the side of an object For example a chain may rub against the inner side of the front derailleur until the derailleur breaks. As a rule of thumb, shear strength is two-thirds of tensile strength.
Shear test
A method of separating two adhesive bonded materials by forcing (either by compression or tension) the mating faces to slide over each other. The force exerted is distributed over the entire bonded area at the same time. Strengths are recorded in pounds per square inch (psi).
Sheathed glow plug
Sheathed-type glow plug
A single-pole glow plug having a tubular heating element with a heating coil or a heating and regulator coil enclosed in a thermally conductive insulator ceramic.

Sheath flame
The outer area of an oxyacetylene flame surrounding the inner cone and the flame feather
Abbreviation for Sealed Housing Evaporative Determination System
Shedder drip molding
A metal strip spot-welded below the roof drip rail to deflect rain water away from the door seal
Shed System
The longitudinal curve of a vessel’s decks in a vertical plane. Due to sheer, a vessel’s deck height above the baseline is higher at the stem and stern than at amidships
Sheer strake
The course of shell plating at strength deck level
Sheet metal
Steel metal in the form of a thin layer or sheet which can be pressed to form panels of the car body.

Sheet metal blank
A flat sheet metal panel before it has been cut and bent to be applied to a panel of a car to repair a damaged section
Sheet metal clamp
Sheet metal clampSheet metal clamp

A lock-grip pliers with wide, flat jaws used to secure sheet metal parts for welding or to bend small sheet metal parts along the edges of the jaws. When used for bending sheet metal, they may also be referred to as bending pliers

Sheet metal cutter
Any tool used to cut sheet metal. Some are Shears while others are power driven units operated by hand or secured to a bench.

Sheet metal folder
Sheet metal folderSheet metal folder

A machine used to bend sheet metal along a predetermined line using mechanical force

Sheet metal remains
A strip of metal left on the edges alter the bulk of a panel has been cut out; this strip is then removed carefully to ensure that the flanges required on adjacent panels for welding in the new part are not damaged and to avoid cutting out excessive material
Sheet metal roller
Sheet metal rollerSheet metal roller

A large machine to curve or roll metal in a single plane. The machine is hand-operated and consists of a frame, three rollers and a hand crank. The rollers are arranged with one top and two bottom rollers, and the degree of curvature is controlled by how closely the bottom rollers are set in relation to the top roller. The pressure of the bottom rollers against the top roller causes the metal to curve

Sheet metal screw
Sheet metal screwSheet metal screw

A straight shank fastener for binding any material to metal by cutting its own thread in the metal. Whereas a machine screw could accommodate a nut on its threads, a sheet metal screw cannot.

Sheet molding compound
(SMC) Formerly called Prepreg, SMC is supplied as a lightweight, pliable sheet which consists of a mixture of chopped strand mat pre-impregnated with resin, fillers, catalyst, and pigment. A sheet is placed between the halves of a heated mold and under the application of pressure it conforms to the contours of the mold
Sheet wheel
A vehicle wheel (before the tire is installed) made from aluminum sheet material. Compare Alloy wheel. The manufacturing process of the sheet wheel is comparable to that of the steel wheel but the advantage of the sheet wheel is its reduction in weight (up to 40% compared to a steel wheel)
ShelbyClick image for books on

A vehicle brand of which the 1965-67 350GT and 500GT are milestone cars.

Shelby Cobra
Shelf life
  1. A time limitation for the storage of uncured retread materials (usually 6 months), beyond which certain properties are lost. Storage of materials in a cool, dark, dry environment insures quality.
  2. The length of time a packaged adhesive, coating, or sealer can be stored under specified temperature conditions and remain suitable for use.
Shelf panel
A deep-drawn steel panel fitted horizontally behind the rear seat backrest of a notchback sedan to support the plastic or foam molding that makes up the rear shelf, visible from the outside
The structural case or housing, usually for mounting instruments.

Shell-and-tube flooded evaporators
Use water flow through tubes built into cylindrical evaporator or vice versa.
Shell bearing
Shell bearingShell bearing

A type of bearing used for main bearings and big-end bearings, consisting of a circular housing which can be divided into two halves, and which encloses a pair of bearing shells

Shell expansion
A plan showing the seams and butts, thickness, and associated welding or riveting of all plates comprising the shell plating, framing, etc.
Shell plating
The plates forming the outer side and bottom skin of the hull
Shell type condenser
Cylinder or receiver which contains condensing water coils or tubes.
Shelter deck
A superstructure deck fitted continuous from stem to stern and fitted with at least one tonnage opening located above the freeboard deck.
The coating of iron objects with zinc powder by tumbling them in powdered zinc at about 250-375°C

  1. An eye and face protector held in the hand when welding. It enables a person to look directly at the electric arc through a special lens without being harmed.
  2. A relatively broad protective device which keeps away unwanted liquid or vapor.
Shielded arc
A form of electric welding in which a heavy flux-coated electrode is used.
Any form of Screening.


To change gears.

Shift cables
A term for the cables used to operates gears in some transmissions. In most vehicles rods and joints are used because cables tend to stretch
Shift conversion
The reaction of CO with water to generate carbon dioxide and hydrogen. This process is performed immediately after the reformer and before the preferential oxidizer to reduce CO from approximately 10% down to 0.5% to 0.1% usually through a water gas shift reaction.
Shift down
The action of selecting a lower gear. The British expression is change down.
A device for changing the gearing on a transmission.

Shifter, bar end
Shifter/brake lever
Shifter and brake lever are a single unit. Shimano units are available in this layout, or with the shifter and brake lever as separate units. Shimano calls them STI and Campagnolo calls them Ergo Power
Shifter, Ergopower
Shifter fork
Shifter knob
The knob at the end of a lever. The British term is gear knob
Shifter linkage
A system of rods and joints used to operate the transmission
Shifter mechanism
A system of rods and joints used to operate the transmission
Shifters/brake lever combo
Referred to by Shimano as STI and Campagnolo as Ergo Power. Shifter/Brake Lever combos allow for shifting gears without removing your hands from the handlebars.
Shift fork
Shift forks
Shift forkShift fork

The devices that straddle slots cut in Sliding gears. The fork is used to move the gear back and forth on the shaft.

Shift gate
The mechanism in a transmission linkage that controls the motion of the gearshift lever. The shift gate is usually an internal mechanism; however, in some transmissions — including Ferrari five-speeds and Mercedes-Benz automatics — the shift gate is an exposed guide around the shift lever.
Shift gear
The action of selecting a different gear. The expression in Britain is change gear.
Shift indicator light
(SIL) a system that provides a visual indication to the driver when to shift to the next higher gear to obtain optimum fuel economy
  1. Moving the ship to suit the location of shore cargo loading gear.
  2. Changing gears in a transmission.
Shifting board
Portable bulkhead members, generally constructed of wood planking and fitted fore and aft in cargo holds when carrying grain or other cargo to prevent shifting when the ship is rolling
Shift interlock
A device which prevents different shift forks in the transmission from being moved at the same time, by locking into the inoperative shift fork as the other is being moved; a gearchange cannot be made unless the inoperative shift fork is in its neutral position
Shift into
The act of shifting into another gear, such as shift into second (shift into second gear) or ‘shift into high’ (shift into high gear). In Britain, the expression is change into.
Shift Keying
Shift lever
  1. A device which is attached to the side of a steering column or to the center console which will allow the operator to change the gears of the transmission. Also called gear lever.
  2. A lever inside an automatic transmission which connects the selector lever cable to the manual valve of the control valve body.
  3. A component used in pre-engaged starter motors to force the pinion against the flywheel ring gear
Shift linkage
The rods, levers, etc. used to transmit motion of the shift lever into movement of the gears in a Gearbox.
Shift lock
Shift on the fly
The ability of a four-wheel-drive vehicle to be shifted between two-wheel drive and four-wheel drive while the vehicle is in motion.
Shift point
This refers to the point, either in engine rpm or road speed, at which the transmission should be shifted to the next gear.
Shift rail
Shift rails
Sliding rods upon which the Shift forks are attached. Used for shifting the manual transmission.
Shift up
A term meaning to shift to a higher gear
Shift valve
A valve in an automatic transmission which raises the oil pressure as the vehicle speed increases. In Britain it is called the change valve.
A thin Spacer installed between two parts to increase the distance between them.

A condition where the front wheels shake or vibrate from side to side because the front end is out of alignment or the tires are out of balance or the suspension has worn components. Also called judder.

Shim pliers
Shim-type head gaskets
A hard thin, high-performance steel head gasket that raises the compression ratio
Shim under bucket
A valve adjusting system where the valve clearance is adjusted by placing an appropriate thickness of shim under the tappet instead of using an adjusting screw.
Shingler’s hammer
A hammer with a blunt side on one end of the head and an axe-like blade on the other side of the head.
Shiny side
Trucker slang for Top of the trailer as in ‘Keep your shiny side up and your rubber side down.’
Freight carried by a truck. Similar to cargo

Shipments, value of
Summation of value of shipments produced by establishment, receipts of custom and repair revenue.
Shipping Weight
The dry weight of a vehicle including all standard equipment, but excluding fuel and coolant.
A slope on which a ship is built and down which it slides to be launched.
Abbreviation for Super High Output Engine
Shock absorber
Properly called a Damper, this is an oil filled device used to control spring oscillation in the Suspension system. At least one shock absorber is found at each wheel.

Shock absorbers
Shock absorber tower
A sheet metal panel of hollowed or box-section design that is spot-welded to the body and serves as an anchoring point for the top shock absorber mount
Shock loading
Pre-setting a shock absorber to a soft or stiff level
Shockproof switch
A switch that is resistant to damage that may be caused by an impact
An abbreviation for shock absorbers.

In the brake system, a metal plate that supports the brake lining and absorbs and transmits braking forces.

Shoe anchor
The point in a drum brake system where the braking forces are transmitted to the chassis
Shoe grinder
Shoe heel
Shoe Hold-downs
Shoe return spring
Drum brake spring that retracts the brake shoe when brakes are released.


Shoe toe
The accelerator pump discharge nozzle; squirts extra fuel into the throttle bore when the accelerator pump circuit is pressurized by the pump piston
Small pump-discharge restrictions in the cluster assembly. These small cavities prevent accelerator pump pullover feeding from the pump system at high airflows
Shooting brake
An old term for station wagon. It refers mainly to larger British station wagons with wooden rear and side panels that were popular during the early post-war such as coachbuilt models by daimler, Armstrong-Siddeley, Allard, etc.
Shop crane
Shop craneShop crane

A lifting device used to remove or lift a motor or transmission

Shopping car
A vehicle similar to a City car, but may be even smaller
Shop primer
A coating which temporarily protects a work from corrosion, e.g., during shipment
A brace or prop used for support while building a ship
Shore hardness
A test method for the determination of indentation hardness of nonrigid plastics
Short arc
A gas metal- arc process which uses a low arc voltage, where the arc is continuously interrupted as the molten electrode metal bridges the arc gap.
Short arm
Short arm/long arm suspension
(SLA) A double wishbone suspension system in which the upper wishbone is shorter than the lower one, with both converging slightly at the wheel hub; reduces tire wear due to variations in track and camber angle when cornering

Short arm suspension
Short block
The lower portion of an engine below the cylinder head. It includes the crankshaft and piston assemblies but not the external parts such as head, sump, oil pump, or fuel pump. The opposite is the Long block
Short block engine
An engine with a relatively short crankshaft. Compare Long block engine. Normally a short block engine refers to a 4-cylinder in-line engine or a V-8 engine where either engine has a shorter block than a 6 cylinder in-line engine
Short circuit
  1. An electrical problem in which the hot or positive wire touches ground. It takes a ‘short’ path to ground instead of going through the prescribed component. Usually a short circuit (also called a short) will burn out a fuse or a component.
  2. Electrical condition where part of circuit touches another part of circuit and causes all or part of current to take wrong path.
  3. A defect in a winding of an electric motor that causes part of the normal electrical circuit to be bypassed
Short circuit between the plates
An undesirable electrically conductive connection between the positive and negative plates within a battery cell, making the battery inoperative
Short circuit current
The current flowing freely through an external circuit that has no load or resistance; the maximum current possible.
Short circuit ground
Fault in an electrical circuit allowing electricity to flow into the metal parts of a mechanism.
Short circuiting
A condition which occurs during the scavenging process of a two-stroke engine when some of the fresh mixture entering the cylinder may flow across the cylinder and escape via the exhaust ports without producing any scavenging effect
Short cycling
  1. The condition in which the compressor in a cycling clutch system cycles too frequently
  2. Refrigerating system that starts and stops more frequently than it should.
Short engine
A fully reconditioned engine but without external parts such as head, oil pan, oil pump, or fuel pump, etc.
Short shifting
In a car with manual transmission, you want to shift at the optimum RPMs to take advantage of the maximum power in each gear. However, if you shift long before that optimum RPM, then you are short shifting.
Short stroke engine
An engine where the length of the stroke is shorter than the diameter of the cylinder bore. Theoretically a relatively short stroke improves high end revving ability but is poorer at low-end torque.
Short ton
2,000 pounds.
Short track
Any oval-shaped or circle-shaped course less than one mile long.
A general term for a short manifold or exhaust pipe
Short-type distributor
A distributor without a drive shaft; the drive coupling is located directly at the base of the ignition distributor housing. The opposite is Shaft distributor
Shot bag
A leather bag filled with very fine lead shot or sand over which metal is shaped
Shot blasting
A blasting process in which rounded particles are impacted onto a surface
  1. The outer edges of the tread of a tire.
  2. The outer edges of a road. Shoulders can be dirt, gravel, grass, or paved, depending on transportation needs. Used for stopped vehicles (i.e., emergency break down, pulled over by the police, etc.), for bicycle riding, for pedestrian walking, and for lateral support of the road surface.
  3. The raised portion of a specialized bolt just under the head. It looks like a collar, but it is not removable
Shoulder belt
A restraint belt pulled diagonally across the chest or the shoulder belt portion of a combined lap-shoulder belt.

Shoulder Stud
A stud similar to a collar stud but having the plain portion of a uniform diameter which is larger than the major diameter of the thread, used where the design requirements do not permit the separation of parts produced by a collar.
A term for Harley-Davidson’s third generation overhead-valve Big Twin engine, introduced in 1966.
Show through
Sand scratches in the undercoat visible through the paint
Shrader valve
Shredded wire
Short pieces of fine steel wire mixed into a tread or undertread compound.
To reduce in size.

  1. The size or coverage reduction of automotive paint as it dries. All automotive paints shrink, and if scratches or surface imperfections have not been properly filled, they will show up as the paint shrinks into them.
  2. The volume of natural gas that is transformed into liquid products during processing, primarily at natural gas liquids processing plants.
Shrink fit
A fit between two parts which is very tight. The outer or encircling piece is expanded by heating so it will fit over inner piece. Sometimes the inner piece is contracted by chilling. As the two pieces reach operating temperature or room temperature, the outer piece shrinks and the inner piece (if it was chilled) expands. As a result, the two pieces fit tightly.
A body repair technique used to repair locally stretched areas by using heat or special body hammers.

Shrinking dolly
A special Dolly with a large crowned grid surface, used to facilitate panel shrinking
Shrinking hammer
Shrinking hammerShrinking hammer

A special hammer with faces shaped to allow for correction of locally stretched sheet metal. When shrinking metal, the panel is beaten into the recesses of the grid, which help stretching

Shrink tube
A thin plastic tube which shrinks in diameter when heated. It is used primarily in covering exposed wire splices.

Shrink wrap
A clear plastic film, often a foot or more wide used to protect something from dust and moisture.
  1. A metal enclosure around the fan, engine, etc., to guide and facilitate the flow of air.
  2. Housing over condenser, evaporator, or fan.
Abbreviation for Strategic Highway Research Program where several areas are addressed:

  • Anti-icing/Road Weather Information Systems (RWIS)
  • Concrete assessment and rehabilitation
  • High performance concrete
  • Innovative pavement maintenance materials
  • Pavement preservation
Abbreviation for Short Term Fuel Trim
Abbreviation for Short Term Fuel Trim Bank 1
  1. To bypass or turn aside.
  2. An alternate or Bypass portion of an electrical circuit.
  3. A colloquial term for to crash.
  4. A crash, especially one caused by running into the back of the vehicle in front of you
  5. Type of field coil with a specific resistance placed in parallel with an ammeter.
Shunt firing
A short circuit at the firing end of a spark plug, caused by electrically conductive deposits. Also called shunting.
A short circuit at the firing end of a spark plug, caused by electrically conductive deposits. Also called shunt firing
Shunt winding
A wire coil forming an alternate or Bypass circuit through which the current may flow.
When a system is not supplying or receiving power (the process of decreasing the power to zero).

Shut line
The line between a closed door and the bodywork
Lines in the body where two body parts abut each other, such as where a door meets a fender. Can also be a seam where two immovable parts meet i.e., plastic bumper cover meets quarter panel.
Shutoff Device
Shut-off switch
Shut-off Valve
A curved metal vane or blade of a Hall generator or Hall effect distributor to block the magnetic field from the Hall Effect pick-up. The shutter is attached to the rotor and is grounded to the distributor shaft

Shuttle valve
A valve in which the actuating member shuttles back and forth diverting pressure from one channel to another
  1. Abbreviation for Spark ignition
  2. Abbreviation for SI Units (Système international d’unités)
Arrangement of Ports when intake or exhaust valves are in pairs which allows two-into-one passages to be cast into the cylinder head. For example, with the usual valve arrangement in a four-cylinder engine the head can be designed so only two ports connect to the intake manifold and only three to the exhaust manifold. Also, when the engine cylinders are connected solidly together (as in the Vega block) instead of being totally surrounded by Water jackets, the cylinders are said to be siamesed.
Abbreviation for Standard Industrial Classification on Industry class that represents a level of organization of production by type of specialization. Currently the 1980 Standard Industrial Classification is in effect identifying each industry at the 4 digit level. The term has been replaced by NAICS
Abbreviation for Side impact dummy
Side aperture panel
Side bumper panels
Large plastic body side moldings attached to the lower body sides which protect the body against road debris, road salt corrosion, and mechanical impact. Sometimes called Sacco panels because they were introduced by Bruno Sacco, the chief designer at Mercedes-Benz
  1. An addition to a motorcycle which is added to its side. It has an outboard wheel and is designed to carry a passenger or luggage.
  2. Small carriages attached to the side of a motorcycle to provide extra carrying capacity.
Side clearance
Side curtain
The early name for side windows which were made of celluloid in a rigid frame supported by the sides of the body and the doors; some had a hinged flap through which the driver could extend his hand for signaling purposes. On classic roadsters, the entire assembly of sliding windows and flaps; wedge-type side curtains permit the side curtain brackets to be wedged into the door plates without bolts; regular spring-type side curtains are mounted to the doors by means of wing nuts or bolts. The curtains can be stored behind the rear seat Squab or in a pocket at the back of the front seats
Side cutters
A tool like a pair of pliers except the end opposite the handles have sharp edges used to cut wire, etc. The British term is end cutters or end cutting pliers
Sidedraft carburetor
A carburetor in which the air passes through the carburetor into the intake manifold in a horizontal plane. Contrasts with a Downdraft carburetor.
Sidedraught carburetor
British spelling for Sidedraft carburetor
Side electrode
The ground electrode at the side of the threaded part of a spark plug shell
Side flasher
A small amber or red signal light located in the side of the front or rear fenders
Side Gauge
Side gear
Side-hung float
Float design has a pivot axis that is perpendicular to the vehicle axles. It has slightly better float control and fuel handling during acceleration and braking than its center-pivoted counterpart
Side impact
Side impact air bag
Fabric bags installed in the doors of some cars that inflate rapidly during a side impact collision. Inflation occurs at speeds of 12 miles per hour or higher, preventing passengers from hitting their heads against the windows or pillars of the car.
Side impact bar
A longitudinal reinforcing beam in a car door, designed to withstand side impact. Also called Side impact intrusion beam
Side impact dummy
(SID) A dummy developed to investigate the effects of side impact crashes
Side impact intrusion beam
A metal beam in the door or along the side of the passenger compartment that adds additional protection in the case of an accident. It reinforces the side of the car.
Side impact standard
Side-lift jack
A low-intensity white lamp usually located on the side of front fender ahead of the front wheel. It is usually illumined in a steady glow when the signal lights are activated.
Sidelight pod
A design feature of older cars that had their side or parking lights incorporated into a separate sheet metal molding on top or at the side of the front fenders
Side Loader
A refuse truck which is loaded from the side.
Side marker lamp
A low-intensity lamp mounted on the side of a vehicle to indicate its presence when seen from the side
Side marker light
A low-intensity lamp mounted on the side of a vehicle to indicate its presence when seen from the side
Side member
A box-section member inboard of the outer sill that often runs from the front to the rear of the car and provides reinforcement of both sides of the floorpan
Side molding
Side panel
  1. A Quarter panel between the B-pillar and the rear.
  2. An Aperture panel.
  3. A vertical panel on the inside of a body shell, e.g., the panel joining the lock pillar to the rear wheel housing.
Side pattern
Side pipe
An exhaust pipe running along the side of the car. Compare Lakers or Lakes pipes
Sidepull brake
Sidepull brakeSidepull brake

A bicycle brake where the cable attachment is on one side rather than in the middle

Side radiator guard
A molded cover panel fitted to the sides of the radiator to protect it from water splashes
Side rail
Side ring
A demountable metal flange to hold the tire on the rim base. It can be self contained, locking into the Gutter, or may be held in place by a Lock ring, depending on the type.
Side rod

Side scoop
An air intake for the engine and/or for cooling on mid-engine or rear-engine cars; typically found on sports cars such as the Ferrari range
Side Service Valve
Side shaft
Side shake
Side shift
Damage to the frame when the vehicle has been hit from the side
Side skirt
An extra body panel fitted over the sills (for cosmetic reasons only)
Side step
A step plate below the doors to facilitate entry into the relatively high cabin of a commercial vehicle
Side styling
  1. Body damage caused by a car hitting an obstacle at an acute angle, causing the panels to be dented over a relatively large area.
  2. To scrape along the side of a car.
Side valve
Valves positioned at the side of cylinder
Side-valve engine
(SV) An engine with the valves to the side of the cylinders
  1. That portion of a tire between the tread and bead.
  2. The vertical part of the box section of a side member
Sidewall awareness
Alert drivers recognize the potential of damage to the tire sidewalls because of low inflation or high-speed cornering.
Sidewall deflection
The bulge of the sidewalls of the tire on the ground. The deflection is significant when the tire pressure is low. All radial tires exhibit some deflection when normally inflated, so tire pressure is ignored under low pressure in the belief that it is still normal. Driving at highway speeds with low pressure will cause the tire to overheat, ruin the tire, increase fuel consumption, and affect handling.
Side window
SI engine
A spark ignition engine or gasoline engine internal combustion engine of the reciprocating type in which an air/fuel mixture is compressed and then ignited by an electric spark. It is unlike a diesel engine
Sight glass
  1. A viewing glass or window set in the refrigerant pipe of a car’s air-conditioning system, usually in the top of the receiver-drier, which allows a visual check of the refrigerant passing from the receiver to the evaporator. The fluid should be clear and free from foam
  2. A glass window in the liquid line, the top of the receiver-drier, or a test manifold, for checking refrigerant flow.
  3. Glass tube or glass window in refrigerating mechanism. It shows amount of refrigerant or oil in system and indicates presence of gas bubbles in liquid line.
Sighting point gauge
A device incorporating a sighting pin, used to measure car bodies for misalignment
Sigma welding
  1. To indicate a change in direction (turning, stopping, etc.).
  2. An indicator.
Signal amplifier
Any device, such as the booster venturi, that amplifies a vacuum signal
Signal indicator
Signal light
The small lights which blink on either side of the front of the vehicle and either side of the rear of the vehicle. Some early cars (like the Austin and Flying Standard) had small illuminated arms that flipped out from the B-post instead. The purpose of signal lights is to warn other drivers of a change in direction when turning a corner or changing lanes. Also called direction indicator. In Japan they are called winkers.
Signal light warning light
A light on the instrument panel which flashes when the signal lights are operating. Usually this light is in the shape of a green arrow. On some cars, like Cadillac, a secondary light is mounted in a pod on the upper edge of each front fender and in a pod inside the cab above the backlight (i.e., back window). Also called direction indicator warning light.
Signal Rotor
A model of automobile manufactured by Buick Division of General Motors from 1998
Abbreviation for Signal Return (sensor ground)
Abbreviation for Shift indicator light

  1. A muffler.
  2. A device in an air-conditioning system designed to minimize pumping sounds from the compressor.
Silencer shaft
Silencer-tailpipe tool
  1. A chisel-type tool with several cutting edges to cut muffler sleeves without damaging tailpipes.
  2. An L-shaped tool whose short end is driven between the silencer and tailpipe to break the bond
Silent chain
  1. A quiet timing chain with V-shaped teeth
  2. A type of chain with teeth formed on its links to engage with the teeth in the sprockets. Silent chains drives are not truly silent. The links in a silent chain drive, however, engage with the sprocket teeth with little impact or sliding, and as a result a silent chain produces less vibrations and noise than other chains. The amount of noise generated by a silent chain drive depends of many factors including sprocket size, speed, lubrication, load, and drive support. A link belt silent chain includes removable links joined by rivets or interlocking tabs. These chains offer the advantage of installation without dismantling drive components, reducing inventory, and increasing temperature ranges. Also called Inverted-tooth chain
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Oldsmobile Silhouette

A model of van manufactured by the Oldsmobile division of General Motors from 1990-2004

A common mineral (silicon dioxide) found as sand, quartz, etc., used in the manufacture of glass, ceramics and abrasives
Silica gel
  1. A form of silica capable of absorbing large quantities of water, used to keep electronic apparatus, etc., dry
  2. A highly absorbent drying agent, usually located in the accumulator or receiver-drier, used to remove moisture from refrigerant.
  3. absorbent chemical compound used as a drier. When heated, moisture is released and compound may be reused.
Silica sand
A form of silica used for Sherardizing or mechanical plating
  1. A non-metallic chemical element occurring in several forms (principally sand and rock), used in the manufacture of glass and steel (as well as transistors etc.)
  2. A semiconductor material made from silica, purified for photovoltaic applications.
  3. A non-metallic substance that adds strength and toughness to copper to help form a bronze alloy.
Silicon bronze
An alloy made of 95% to 98% copper plus a small amount of silicon added for strength. Small amounts of manganese and aluminum may also be added for strength, and lead may be added for machineability. Silicon bronze is non-magnetic with a high degree of thermal conductivity and high corrosion resistance against sea water, gases, and sewage. It is often used by the utilities industry for pole line hardware and switchgear equipment, mine sweeping, sewage disposal equipment, food machinery, marine applications, plumbing and liquid handling. Surprisingly, silicon bronze is only a low to moderate conductor of electricity, though it is a better conductor than stainless.
Silicon carbide
A material of excellent abrasion and corrosion resistance used in bearings and mechanical seals
Silicon-controlled rectifier
(SCR) Electronic semiconductor which contains silicon. Controls current by timing pulses.
A silicon compound with a high resistance to heat, water, and chemicals, and with good insulating and lubricating properties; used in oils, polishes, sealants, etc.
Silicone adhesives
Adhesive compounds of this base have remarkable stability through a wide temperature range. Chief limitations in present use are their high temperature cure, sensitivity to fuels, and relatively high cost. Outstanding high temperature (above 149°C) and low temperature (-73°C) performance have been reported. Highly resistant to oxidation, to ozone, and to corona radiations. Very good dielectric properties.
Silicone brake fluid
A brake fluid which does not absorb water
Silicone Compound
Silicone-rubber sealant
A semi-liquid sealant which keeps out oil and water but not gasoline. Also called RTV sealant
Silicon glove
Silicon steel
An alloy of silicon and chromium with steel, often used for exhaust valves
  1. A longitudinal box-section member of the body shell at floor level, located below the doors.
  2. A box-section crossmember just below the lower edge of the trunklid (when closed).
Sill cover
A non-structural part covering the Sill on its entire length; used on certain designs with separate chassis but also on unitary designs
Sill end piece
A small panel at the front and rear end of the sill that closes off the hollow sill section towards the front and rear wheel arches. Compare Closing panel
Sill membrane
A horizontal stiffening panel between the outer sill and the side member box section; it is ribbed or drilled for extra rigidity
Sillment seal
A gas-tight seal between center electrode of a spark plug and insulator and between insulator and shell
Sill panel
Sill stiffener
Sill structure
The overall design of the sills including outer sills, side member, or inner sill and sill membrane
Silver brazing
Brazing process in which brazing alloy contains some silver as part of joining alloy.
The electrolytic deposition of silver
Silver solder
Similar to brazing except that a special silver Solder metal is used. It is used primarily on bicycle tubing.
Abbreviation for Special Import Measures Act.
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An automobile manufacturer

Simple circuit
The simplest circuit includes an electrical power source, a load, and some wire to connect them
Simple tappet
Simplex chain
A chain with only one row of rollers.

Simpson gear set
It consists of two simple planetary gear sets with a common sun gear and internal gears of different diameter; the planet carrier of one set is fixed to the internal gear of the other set
Simpson planetary gear set
It consists of two simple planetary gear sets with a common sun gear and internal gears of different diameter; the planet carrier of one set is fixed to the internal gear of the other set
Sine wave, AC current
Wave form of single frequency alternating current; wave whose displacement is sine of angle proportional to time or distance.
  1. A small, lightweight motorcycles. What the bike lacks in overall power, it gains in its lightweight, small size that makes it easy to ride even if it has a large engine displacement.
  2. Any single cylinder engine vehicle (especially, a motorcycle)
Having a piston or pistons of a reciprocating engine or pump that are pressurized on only one side
Single-anchor self-energizing brake
A type of servo brake where both shoes pivot about one fixed point
Single Barrel
Single barrel carburetor
Single-barrel carburetor
A carburetor with one throttle opening or barrel from the carburetor to the intake manifold.

Single bead
A tire built with only one wire bundle in the bead.
Single-bed 3-way catalytic converter
A converter for the control of HC, CO, and NOx emissions, consisting of one three-way catalyst; in combination with an oxygen sensor, this type of converter yields the lowest emission values
Single-bed oxidizing converter
A converter with one catalyst bed for HC and CO control
Single brake system
A brake system using only one hydraulic circuit for all wheels.
Single cell test
A test of the fuel cell performance based on one unit cell. The test is typically a laboratory scale test in which several variables can be adjusted in order to obtain data over a wide range of conditions, such as temperature, current density, fuel and oxidant flow rates, etc. The outcome of a single cell test may be a polarization curve, a voltage stability plot, or other data related to fuel cell performance.
Single-circuit braking system
An old form of hydraulic braking system in which a single circuit serves all four brakes. Not to be confused with Single-line braking system
Single-circuit line
A transmission line with one electric circuit. For three-phase supply, a single circuit requires at least three conductors, one per phase.
Single coat
A Coat of paint, with each stroke Overlapping the previous stroke by 50%.

Single-coil twin ignition
In the early days of straight eight engines, a distributor with two sets of contact points, firing alternately
Single-connector system
An electrical circuit, where only one wire comes from the voltage source to the load. To complete the circuit, the electricity uses the metal body of the vehicle
Single crystal silicon
  1. (Czochralsky) An extremely pure form of crystalline silicon produced by dipping a single crystal seed into a pool of molten silicon under high vacuum conditions and slowly withdrawing a solidifying single crystal boule (rod) of silicon. The boule is sawed into thin silicon wafers and fabricated into single-crystal photovoltaic cells.
  2. Silicon cells with a well-ordered crystalline structure consisting of one crystal (usually obtained by means of the Czochralsky growth technique and involving ingot slicing), composing a module. Ribbon silicon is excluded.
Single-cut file
A file with teeth in only one direction and used for filing soft material
Single-cylinder engine
An engine with just one cylinder such as used on some motorcycles and utility engines (e.g., lawn mower engine, water pump, portable generator, etc.)
Single-decker bus
A bus with one storey or deck.

Single Drop Trailer
A type of flatbed trailer. The rear is closer to the ground than the front. Also called single drop platform
Single-grade oil
Oil suitable for use within a narrow temperature range; outside this range, its flow characteristics will not allow adequate lubrication. Also called straight-weight oil. Compare Multigrade oil
Single lane
Control of traffic through construction zones where there is only one lane and traffic must wait until oncoming traffic passes first. It is monitored by a flag person or by electrical signal lights.
Single leading brake shoe
The use of a single hydraulic plunger and a common pivot point which expands two shoes against the drum with equal pressure whether braking from forward or reverse direction. The leading brake shoe is usually called the Primary Shoe and trailing shoe is called the Secondary Shoe.

Single-leaf spring
A suspension spring which has just one flexible beam
Single-line braking system
A braking system in which a single line is used to connect towing vehicle and trailer. It is not to be confused with Single-circuit braking system
Single master cylinder
A master cylinder with only one pressure chamber, used in single brake systems.
Single overhead cam
(SOHC) The camshaft is located between the valves and is driven by a chain or belt from the crankshaft; the valves are normally opened by short rocker arms.

Single-overhead cam
(SOHC) An engine with a single overhead camshaft to operate both intake and exhaust valves.

Single overhead camshaft
(SOHC) The camshaft is located between the valves and is driven by a chain or belt from the crankshaft; the valves are normally opened by short rocker arms.

Single-overhead camshaft
(SOHC) An engine with a single overhead camshaft to operate both intake and exhaust valves.

Single phase electrical
A circuit energized by a single alternating electromotive force.
Single-phase motor
Electric motor which operates on single-phase alternating current.
Single-piece rim
A one-piece rim
Single-piece wheel
A one-piece wheel
Single Piston
Single-piston caliper
A disc brake caliper that has one hydraulic cylinder and piston, unlike calipers with two or four pistons.
Single Piston Pump
Single-pivot steering
A steering system in which a beam axle is pivoted at its mid-point; rare except on horse-drawn vehicles and trailers.

Single-plate clutch
A normal type of clutch, with one driven plate; usually dry (i.e., without oil).

Single point injection
(SPI) A gasoline fuel-injection system which sprays fuel under pressure into the intake air at one place, usually the throttle body on the inlet manifold. It is less complicated than a multi-point injection system but achieves better carburation than a carburetor.

Single-pole, double-throw switch
(SPDT) Electric switch with one blade and two contact points.
Single-pole, single-throw switch
(SPST) Electric switch with one blade and one contact point.
Single rate spring
A spring with a constant spring rate. For example, if a 100-pound force deflects the spring by one inch, an additional 100 pounds will deflect it one more inch, and so on until the spring either bottoms or fails. The opposite of Progressive rate spring.
Single roller chain
Single-Source Leasing
A service in which companies can lease both drivers and trucks from the same source, rather than having to procure them from different companies.
Single-spark ignition coil
In a distributorless ignition system with an odd number of cylinders, each cylinder requires its own ignition coil; distributor logic on the low-voltage side performs the voltage distribution to each coil.

Single-stage compressor
Compressor having only one compressive step between inlet and outlet.
Single Thread
A single-start thread having lead equal to the pitch.
Single-throw Switch
Single-throw switch single-pole
(SPST) Electric switch with one blade and one contact point.
A trail just wide enough for one person or bicycle
Single-tube shock absorber
A common type of shock absorber with the working cylinder and reservoir contained in one tube.

Single-wheel suspension
Single wire circuit
An electrical system in which the hot line is in a wire, but the ground line uses the frame.
Single wire system
Lighting circuit which uses car frame for return ground line
Deep or large voids underneath the roadway surface.
Sink in
A tendency of a hardened filler to settle excessively, making the feather edges of the filled area stand out on the painted surface
  1. To manufacture parts from powdered metals by heating or pressure or both.
  2. The fine powdered metal itself
Sintered bronze
Tiny particles of Bronze pressed tightly together so that they form a solid piece. The piece is highly porous and is often used for filtering purposes.
Sintered metal brake pad
A type of brake pad made of Sinter and is designed to reduce noise and increase performance and life.
The process of fusing a metal-powder mixture together under high heat and pressure.
Abbreviation for State Implementation Plan

Fine lines or grooves cut into the tread of tires. They allow the tire to flex and give better traction on wet surfaces. They may also reduce tire noise.

Abbreviation for Side Impact Protections System
The manufacturer’s name for the air bag system

  1. Abbreviation for Supplementary Inflatable Restraint
  2. Abbreviation for Supplemental Inflatable Restraint
Abbreviation for Solenoid Idle Stop
Sissy bar
  1. A chrome rail which projects up from the back of a motorcycle saddle.
  2. The backrest mounted behind the passenger’s portion of the saddle
Sister ships
Ships built on the same design.
Abbreviation for Spontaneous Ignition Temperature. The temperature at which an oil ignites of its own accord in the presence of air or oxygen under standard conditions.
Sitting position
SI units
System of coherent metric units (Système International d’Unités) proposed for international acceptance in 1960.
SI unit system
(le système international d’unités) Metric system of measurement adopted by most technical industries throughout the world.
Six banger
Six cylinder engine.
Six-cylinder engine
An engine with six cylinders; may be in-line (a straight six) or in a V-layout (a V-6)
Six-light sedan
An old designation of a four-door body style that features another small quarter window behind the rear side doors, resulting in three side windows per side or six windows overall
Refers to a special triple two-barrel induction system used on some Chrysler V8 engine in the late 1960s and early 1970s. However, other special heavy-duty parts were used in engine that came from the factory equipped with this induction system, so six-pack is frequently used as an adjective to describe other engine components used on these engines. E.g., six-pack connecting rods
Six-speed shifter
Six-speed transmission
A manual transmission with six forward gears.

Sixteen valve engine
(16V) A four-cylinder engine with four valves to each cylinder. This system permits more air-fuel into the cylinder and exhaust out of the cylinder.
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Pontiac 6000

A model of automobile manufactured by the Pontiac division of General Motors from 1982-1991.

Sixty-One (Cadillac)
A 1939-51 Cadillac model of which the 1948-49 Coupe Fastback models are milestone cars. Also see history of Cadillac.
Sixty Special
A vehicle brand of Cadillac of which the 1948-49 models are milestone cars. Also see history of Cadillac.
Sixty-Two (Cadillac)
A 1940-64 Cadillac vehicle brand of which the Sedanet and Convertible DeVille for 1948-49 are milestone cars. Also see history of Cadillac.
Six Value Condition Number Scale
See Condition Numbers
Size designation
Size marking
The first part of a tire marking molded on the sidewall, giving the tire’s width in millimetres
Size markings
Size Tubing


SJAPI SJ Category

An API engine oil adopted in 1996 for use in gasoline engines of 1997-2001 passenger cars, vans, and light trucks. Oils meeting API SJ requirements have been tested according to the American Chemistry Council (ACC) Product Approval Code of Practice and may use the API Base Oil Interchange and Viscosity Grade Engine Testing Guidelines. It replaces API Service Category SH and was replaced by SL in 2001. These vehicles can benefit from the modern SM oils.

The action of sliding across an icy road. Usually caused by excessive speed and locking the wheels. If you apply the brakes on an icy road, you have no ability to steer or control the vehicle–instead you will skate in the direction your vehicle was moving.
Skate board
Trucker slang for a flatboard trailer
Skate Wheel Conveyor
Conveyer that moves product using wheels. See Gravity Conveyor
A deep, vertical, fin-like projection on the bottom of a vessel near the stern
Skeleton construction
A modern construction layout of the unitary type, using a skeleton-like assembly as the main structural member, thus relieving stress from the body sheet metal.

The arrangement of laminations on a rotor or armature to provide a slight diagonal pattern of their slots with respect to the shaft axis. This pattern helps to eliminate low-speed Cogging effects in an armature and minimize induced vibration in a rotor.
A pin with a loop at one end for insertion and removal.

  1. A sideways slip or slide of a wheel through failure to grip the ground.
  2. To slide sideways (often out of control).
  3. To slide in a straight line (as after sudden braking with, maybe, locked brakes).
  4. A short-distance moving of logs or felled trees from the stump to a point of loading.
Skid braking system
Skid control system
A system designed to respond to a locking wheel by relieving hydraulic pressure to the locking brake.
Skid depth
Skid lid
A helmet.
Skid mark
The mark left on the road surface by the tires, as a result of emergency braking
Skid pad
A large area of smooth, flat pavement used for various handling tests. Roadholding is measured by defining a large-diameter circle (Car and Driver magazine uses 300 feet) on the skidpad and measuring the fastest speed at which the car can negotiate the circle without sliding off.
A large area of smooth, flat pavement used for various handling tests. Roadholding is measured by defining a large-diameter circle (Car and Driver magazine uses 300 feet) on the skidpad and measuring the fastest speed at which the car can negotiate the circle without sliding off.
British term for Skidpad.
Skid plate
A steel, aluminum, or plastic shield attached to the underside of the chassis to protect vulnerable components (oil pan, transmission, differentials, and transfer cases) from off-road obstacles. Also called Sump guard
Skid trail
A temporary, nonstructural pathway over forest soil used to drag felled trees or logs to the landing.
Ski flap
A flap in the rear bulkhead (behind the rear seat), for long, thin loads (like skis)
The outer surface or body panel.

Skin condenser
Condenser using the outer surface of the cabinet as the heat radiating medium.
The length of wire that protrudes from a cable form or housing and extends to the soldered connector
  1. The formation of a film on a thick paint layer before the solvents in the layer under it have evaporated
  2. When adhesives and sealers contain fast drying solvents, there is a tendency for the applied film to dry rapidly at the surface which slows down the evaporation of the solvent that remains in the film. This condition can lead to blistering, checking or cracking, particularly if the film is exposed to temps near or above the boiling point of the solvent.
  3. Many coatings, particularly oxidizing types, have a tendency to skin over when left exposed to the air in an open vessel or in a partially filled container. Later when the material is forced through a spray gun, the air breaks the skin into a number of particles which appear on the work as specks. This condition can be overcome by straining the coating and by taking care to store it in completely filled containers.
  1. Colloquial term for tires.
  2. A covering (usually plastic) for skis on a snowmobile.
A popping feeling in a bicycle drivetrain when you pedal hard; it occurs when a cog is worn out and when you install a new chain on worn cogs
  1. SkirtSkirt

    The portion of the piston below the rings and Bosses. It absorbs the thrust caused by the crankshaft as it makes contact with the cylinder wall.

  2. A cover for the rear fender cutout.
Skirt expander
Skirt expanding
Skirt piston
The action of cutting into something or cutting away rubber from an injury in preparation for a section repair.
SkyhawkClick image for books on
Buick Skyhawk

A model of automobile manufactured by the Buick division of General Motors from 1975-1980, 1982-1989

SkylarkClick image for books on
Buick Skylark

A model of automobile manufactured by the Buick division of General Motors from 1953-1954, 1961-1972, 1975-1998

A glass covered framework fitted over a dock opening for admitting light and air into the compartment below. A pop-up window in the roof of a trailer
  1. Abbreviation for Special ledge
  2. SLAPI SL Category

    An API designation of gasoline engine oil for 2001-04 passenger cars, sports utility vehicles, vans and light trucks Oils meeting API SL requirements have been tested according to the American Chemistry Council (ACC) Product Approval Code of Practice and may use the API Base Oil Interchange and Viscosity Grade Engine Testing Guidelines. It replaces API Service Category SJ and was replaced, in turn, by the latest SM oils.

  1. The amount of free play in a chain or belt too much slack could cause the chain/belt to slip and jump the sprockets; too little slack (the chain seems tight) causes excessive wear on the final drive system.
  2. Brake actuator stroke prior to effective application of force.
Slack adjuster
An adjustable member that transmits brake application force and permits compensation for lining wear.
Formation of hard deposits on boiler tubes and/or piston crowns, usually due to the presence of sodium, vanadium, and sulfur.
Slag inclusions
Non-fused, non-metallic substances in the weld metal.
Slant engine
This is an in-line engine in which the Cylinder block has been tilted from a vertical plane. Also called Inclined engine
A colloquial term for a Bumping blade
SLA suspension
Abbreviation for Short arm/long arm suspension
Slatted grille
An aerodynamic radiator grille developed by Ford in 1976. The horizontal aerofoil grille elements are shaped like aircraft wings to allow the cooling air to flow towards the radiator at low speeds, whereas excess airflow is directed upwards across the front of the car at higher speeds to produce an effect similar to that of a spoiler
Slave con rod
A connecting rod of two-stroke dual piston engines which is articulated on the master con rod, not directly on the crankpin.

Slave cylinder
A small cylinder containing a piston which, under hydraulic pressure from a master cylinder, operates the brake shoes or pads in hydraulic brakes or the working part in any other hydraulically operated system (such as a clutch slave cylinder).

  1. A snowmobile.
  2. A vehicle which is in poor shape and worth little or nothing.
Sledge hammer
A large, heavy hammer usually with a long handle. The head is double sided so that either end can be used to strike an object
A sleeping compartment mounted behind a truck cab, sometimes attached to the cab or even designed to be an integral part of it.
Sleeper Team
A pair of truck drivers who take turns driving and resting.
  1. A tube fitted externally over two cylindrical parts in order to join them.
  2. A cylindrical insert.
Sleeve bearing (SLV)
  1. Any bearing of tubular or sleeve-like construction
  2. A bearing that resembles a short length of bronze tubing with grooves to direct oil flow. Good for low noise level.
Sleeve nut
A long nut with right or left threads for connecting two rods to make an adjustable member.

Sleeve valve
Consists of metal sleeves located between the piston and cylinder wall. When moved up and down, holes in the sleeves coincide with inlet and exhaust parts to provide passage for the gases at the right time.
Slewed axles
Axles that are not parallel.
A very wide tire, without a tread pattern, designed to provide a maximum amount of traction. It is used for racing on dry surfaces.
Slide caliper
Slide carburetor
A type of carburetor often used in motorcycle engines, in which a slide valve modifies the venturi of the carburetor
Slide hammer
Dent PullerSlide Hammer Dent Puller

A tool with a long round shaft on which a hammer weight slides; the force produced by quickly moving the weight towards the end of the shaft is used for loosening or pulling off tight parts; often used in combination with pullers.

Slide-in camper
Slide-in camperSlide-in camper

A structure which fits into a truck bed for camping purposes. It usually has beds and possibly cooking and washing facilities. Also called a Truck camper or just camper.

Slide-on camper
  1. (CVT) A device which senses the position of the half of a primary pulley that slides.
  2. The lower (moving) tube on a bicycle suspension fork which is attached to the front hub.
  3. A mechanism that allows a tandem axle suspension to be moved back and forth at the rear of a semitrailer, for the purpose of adjusting the distribution of weight between the axles and fifth wheel.
Slider caliper
Slider caliper disc
Slider caliper disc brake
Slide Sunroof
Slide valve
A valve that slides across an aperture to expose the port or opening
Sliding caliper
  1. Similar to a floating caliper, but instead of riding on guide pins and bushings, the caliper slides on machined ways and is retained by keys or spring plates.
  2. Single piston calipers which use pins or rails to obtain a self-centering action. The caliper slides on these pins or rails to center over the disc when the brakes are applied.
Sliding-caliper disc brake
A disc brake design with a sliding caliper. In one type, the caliper floats on the caliper frame grooves. The major components are caliper (a casting with one cylinder and piston), caliper frame (casting) which is bolted to the suspension. In another type, the caliper floats on caliper locating pins. A third type, is the floating-frame disc brake. Sometimes subtle design differences are used to differentiate between sliding caliper disc brakes and floating caliper disc brakes, but usually these terms are treated synonymously.

Sliding contacts
An ignition assembly developed by Lucas, that causes the moving contact to slide vertically across the face of the fixed contact when the spark is advanced
Sliding Fifth Wheel
  1. A Fifth wheel mounted to a mechanism that allows it to be moved back and forth for the purpose of adjusting the distribution of weight on the tractor’s axles. Also provides the capability to vary vehicle combination lengths.
  2. A fifth-wheel assembly capable of being moved forward or backward on the tractor to adjust the load distribution on the tractor and the overall length of the rig.
Sliding fit
Parts that are assembled so that there is clearance between them so that one part can slide in or on the other. Also called clearance fit
Sliding friction
A frictional resistance to relative movement of surfaces on loaded contact.

Sliding gear
A transmission gear that is Splined to the shaft. It may be moved back and forth for shifting purposes.
Sliding joint
Sliding-mesh gearbox
An obsolete type of transmission or gearbox in which the gears on the layshaft are fixed to the shaft rigidly, whereas the gears on the main shaft can slide on it by means of splines but are otherwise in permanent rotational mesh with the shaft.

Sliding-pillar suspension
A once popular front suspension layout (e.g., in Lancia and Morgan cars), in which a carrier-mounted stub axle slides up and down a vertical pillar with enclosed coil springs providing the suspension; less sophisticated versions were used in several pre-war cycle cars
Sliding side window
A window style of classic roadsters, consisting of aluminum frames with tracks for two sliding window panels made of clear Plexiglas, and with draft seals; on some cars, also furnished with flaps.

Sliding Tandem
A mechanism that allows a tandem axle suspension to be moved back and forth at the rear of a semitrailer, for the purpose of adjusting the distribution of weight between the axles and fifth wheel. Also called a slider.
Sliding T-bar
A drive handle with square drive sliding on round bar for T-handle turning operation
Sliding-vane pump
A positive displacement pump in which an eccentric rotor revolves in an eccentric or circular case. The pumping element consists of multiple blades which slide in slots in the rotor and divide the crescent-shaped fluid space into variable volumes. Some sources state that in the sliding-vane type, vanes do come into contact with the casing, whereas in vane-type pumps a clearance of about 0.004 inches is maintained between vanes and casing.

Sliding weight
A functional part of a Slide hammer that provides the inertia required for the pulling force
A ring on a shaft that throws oil from the shaft before it gets to the oil seal.

Sling psychrometer
Measuring device with wet and dry bulb thermometers. Moved rapidly in air, it measures relative humidity.
  1. A form of Dragster using a rather long thin frame with a very light front axle and wheel assembly.
  2. A maneuver in which the driver of the trailing vehicle in a draft line breaks the draft by turning (usually to the left if on an oval track), propelling the car around the leader.
Slinky bus
A colloquial term for an articulated bus
  1. The relative motion between driving and driven parts.
  2. The difference between the speed of the rotating magnetic field (which is always synchronous) and the rotor in a non-synchronous induction electric motor. Slip is expressed as a percentage of synchronous speed and generally increases with an increase in load
Slip angle
The difference in the actual path taken by a vehicle making a turn and the path it would have taken if it had followed exactly as the wheels were pointed. The slip angle is the result of the tire carcass’s flexibility and is the angular difference between the direction the wheel is traveling and the direction of the tread. If the slip angles of the rear tires are greater than the slip angles of the front tires, the vehicle is said to be oversteering.

Slip Brake Control System
Slip-control differential
Slip differential
Slip friction
Slip-in bearing
A liner, made to extremely accurate measurements which can be used for replacement purposes without additional fitting
Slip joint
  1. A Joint that will transfer driving torque from one shaft to another while allowing longitudinal movement between the two shafts. A variable length connection that permits the driveshaft or axle shaft to change its length as the shaft moves up and down. The British term is sliding joint.
  2. A connection in an exhaust pipe where one pipe slips into another.
Slip joint pliers
Any device which slides on to the main component, e.g., a slip on muffler slides onto the existing exhaust pipe
Slipper piston
A piston with the lower edge cut away so that the Piston skirt is short on the two sides not used as thrust surfaces. Such a design lightens the piston making it easier to accelerate and decelerate, wastes less power, and is easier on the bearings. Cutting away the skirt also allows the Connecting rod to be made shorter but leaves enough room between the Counterweights and the pistons so the overall height of the engine can be reduced.
Slip Regulation
Slip ring
  1. One of several conductive metal rings attached to the rotor shaft in an alternator that periodically changes the direction of current flow.
  2. A conductor band, mounted on an armature and insulated from it. A conductor strip slides on the band as the armature rotates. The function of the slip ring system is essentially the same as a commutator and brushes. Slip rings are also used to transmit current from the armature in a generator application
Slip-ring end bracket
A cover housing the bearing at the slip-ring end of an alternator. At the other end is the Drive end bracket
Slip road
Slip roll
Slip Sensor
Slip stream
  1. A stream of air behind a moving vehicle.
  2. A racing technique in which one vehicle tucks in closely behind another (catches a tow). The total aerodynamic drag acting on the two vehicles is actually less than the drag that acts on each vehicle when they are separated by greater lengths; this allows both vehicles to gain straightaway speed. The lead vehicle cuts into the air acting as a wind break for the following vehicle, and the closeness of the second vehicle reduces the turbulence normally generated at the rear of the first vehicle. Also called Drafting.
Slip tank
A large auxiliary fuel tank mounted in the back of a pickup truck
Slip the clutch
To operate the clutch so that it partially disengages, as when keeping up the revs when driving off; causes wear on the clutch.

Slip Washer
A washer with an opening large enough to slip the washer over a bolt, and under the bold head. Also called a C washer.
Slip yoke
Slip yokeSlip yoke

A component at the front of the first U-joint which accommodates changes in drive shaft length as the rear axle assembly moves up and down with the rear suspension. Internal splines on the U-joint yoke slide in and out on the external splines of the transmission output shaft. This splined coupling also allows the drive shaft to be removed from the vehicle when the rear U-joint is disconnected. The drive shaft may fall to the ground and be ruined if either U-joint breaks while the vehicle is in motion.

To proceed up a hill at a slow arduous pace.
Slop Chute
Chute for dumping garbage overboard.
  1. The percentage of full hydraulic system pressure supplied to the rear brakes by the proportioning valve. Expressed as the ratio of rear pressure to front pressure.
  2. Degree of deviation of a surface from the horizontal, measured as a numerical ratio, as a percent, or in degrees. Expressed as a ratio, the first number is the horizontal distance (run) and the second number is the vertical distance (rise), as 2:1. A 2:1 slope is a 50 percent slope. Expressed in degrees, the slope is the angle from the horizontal plane, with a 90 degree slope being vertical (maximum) and a 45 degree slope being a 1:1 slope.
A colloquial term for an Inclined engine
Sloping headlight
An old headlight type used on the VW Beetle prior to 1967
Slop tank
A container in a tanker into which the residue of tank washing are pumped.
A narrow channel or aperture, especially the groove in the head of a screw which receives the tip of the blade of a screwdriver.

Slotted Head
The head, of a bolt or screw, which has one or more slots across the top to fit a screw driver.
Slotted Nut
A hexagon nut having opposed slots at the end opposite to the bearing face which are perpendicular to the axis, designed for insertion of a cotter to secure the nut in place when used with a drilled fastener.
Slotted Pin
A pin that has a slot, either a square or round bottom, into which an external clip or key is affixed in a locking position.
Slotted piston
Slow charging
The charging of a battery by using a charging current which corresponds to 10% of the battery capacity.

Slow down indicator
An indicator light on the instrument panel that warns the driver to slow down in the event of excessive catalytic converter temperature. A protective warning circuit causes the indicator to flash if the catalytic converter becomes overheated. If the temperature increases beyond a certain second level, the lamp will glow continuously
Slow leak
A tire which loses its air pressure over a period of time. It is usually caused by a small puncture, a leaking tire valve, or a tire that is not properly seated on the rim.
Slow passer
A vehicle off in the distance behind you in your lane that is driving faster than you. When he pulls out to overtake you, he drives at your speed for several minutes before picking up speed again to finish the passing action.

  1. A thick, black, mushy, greasy deposit found throughout the interior of the engine. Caused from a mixture of dust, oil, gasoline, water, and Blowby being whipped together by the moving parts. Some engines oils have Detergent to break down sludge. A composition of Oxidized Petroleum products along with an emulsion of oil and water, forming a pasty substance that clogs oil lines and passages and interferes with engine lubrication. Sludge is formed in engines with neglected oil changes.
  2. Deposits in fuel tanks and caused by the presence of wax, sand, scale, asphaltenes, tars, water, etc. The sludge formed in a #6 fuel oil storage tank is mostly composed of heavy hydrocarbons. Alken Even-Flo® 905 eliminates this type of sludge by breaking the sludge into small particles and re-suspending them in the fuel for more efficient combustion. The sludge formed in diesel storage tanks is a combination of water with fungus and bacteria, which grow on the unevenly mixed water/fuel interface. Adding Alken Even-Flo® 910 and 910S to stored fuel promotes a clean separation of water and fuel, reducing the substrate upon which bacteria and fungus can grow. Since the bacteria and fungus bind to the separated water, they can be removed by draining the water from the storage tank. If draining the storage tank is impossible, EF 905 and 910E will emulsify the water into tiny droplets and break the sludge into such small particles that they will no longer clog filters and will efficiently burn.
  3. A dense, slushy, liquid-to-semifluid product that accumulates as an end result of an industrial or technological process designed to purify a substance. Industrial sludges are produced from the processing of energy-related raw materials, chemical products, water, mined ores, sewerage, and other natural and man-made products. Sludges can also form from natural processes, such as the run off produced by rainfall, and accumulate on the bottom of bogs, streams, lakes, and tidelands.
  1. Unit of mass equal to the weight (in US units) of object divided by 32.2 (acceleration due to the force of gravity).
  2. Detached mass of liquid or oil which causes an impact or hammer in a circulating system.
Condition in which mass of liquid enters compressor causing hammering.
Unresponsive; functioning at below normal rate or level
Sluggish acceleration
To increase speed slowly in an undesirable fashion.

Slurry seal
A thin mix of liquid asphalt and fine aggregate is placed on the street as a preventive maintenance measure to fill in ruts, cracks, and breaks. A thin layer of about 3/8′ to 1/2′ thick is applied by a special truck-mounted paving system. When the slurry seal is applied it may be brown, but gradually dries to black. You can drive on it after it solidifies in 4 to 6 hours. The work must be done during warm, dry weather.
Soft melting snow.

Slush box
A derogatory colloquial term for an automatic transmission used by those who prefer a manual transmission.
A derogatory colloquial term for an automatic transmission used by those who prefer a manual transmission.
Slush molding
A thermoplastic casting in which a liquid resin is poured into a hot, hollow mold where a viscous skin forms; excess slush is drained off, the mold is cooled, and the molded product is stripped out.

Abbreviation for Sleeve bearing
SMAPI SM category

An API designation of engine oil that provides improved oxidation resistance, improved deposit protection, better wear protection, and better low-temperature performance over the life of the oil than previous designated oils. Some SM oils may also meet the latest ILSAC specification and/or qualify as Energy Conserving. It replaces API Service Category SJ and SL.

Small bayonet cap

A 16mm diameter base of a light bulb used in automobile lighting.

Small-block engine
During the ’60s and ’70s, GM, Ford, and Chrysler made two types of V8 engines of the same displacement e.g., 350 cu. in. small-block and 350 cu. in. Big-block. The small-block engine was an enlarged smaller displacement engine (e.g., GM enlarged the 283 to 327 then to 350 by boring the cylinders). The big-block engine was a completely different basic engine size even though it displaced the same as the enlarged small-block engine. Thus, as vehicles grew smaller and more equipment was stuffed into the engine bay, the small-block engine was favored over its larger brother.
Small Cowl and Chassis Bus Type
Depicted by light-duty, non school bus shuttle coaches using a van or RV cutaway chassis.
Small end
The top of a connecting rod, attached to the piston pin
Small end bearing
The smaller bearing of the two on a connecting rod and through which the piston is attached; usually fitted with a plain bearing or a needle-roller assembly
Small gear lever
Colloquial term for Transfer gear lever
Small pickup truck
A pickup truck weighing under 4,500 lbs GVW.
Abbreviation for Sheet molding compound
Abbreviation for Single Module Engine Controller (replaced with PCM)
Abbreviation for Society of Motor Manufacturers and Traders
Fog made darker and heavier by chemical fumes and smoke. A fog-like layer, often brown in color, that hangs over many areas under certain atmospheric conditions. Smog, a contraction of the words smoke and fog, is compounded from smoke, moisture and numerous chemicals produced by combustion (from power plants, automotive engines, etc.) and from natural and industrial processes. Formation of smog is aided by the presence of sunlight which reacts with many chemicals and combustion products such as Hydrocarbons and oxides of nitrogen to form other more noxious Compounds.
The visible product of combustion; a common problem with diesel cars when starting or pulling hard, caused by too much fuel resulting in black smoke, oil (bad rings/piston, valve seals, etc.) resulting in blue smoke, or blown head gasket so coolant getting in the combustion chamber resulting in white smoke.
Smoke meter
An instrument which measures the density of exhaust smoke, especially in diesel engines
Smoke test
Test made to determine completeness of combustion.
Smokey on four legs
Trucker slang for a horse-mounted police as in ‘There’s a smokey on four legs at the next corner.’
Abbreviation for sequential multi-point electronic fuel injection.
The symbol for tin
Snail-cam chain adjuster
Axle-mounted helical cams that allow accurate chain adjustment
A condition when pulling a trailer where it swings from side to side when being towed too fast
Snake bite
A double puncture of an inner tube, caused when the tire compresses down to the rim from hitting an obstacle too hard or by under-inflation of the tire
Snap fastener
A securing device with a projecting knob on one part that is pressed in securely into a corresponding hole on another part, used on some roadsters to attach the convertible top or tonneau cover to the rear deck and/or windshield header.
Snap ring
A split ring or clip that is snapped into a groove in a shaft or in a groove in a hole. It is used to hold bearings, Thrust washers, gears, etc., in place. An internal snap ring is used in a groove in a Housing; an external snap ring fits in a groove cut on the outside of a cylindrical piece such as a shaft.

Snap-splice connector
Solderless connector used to tap an additional wire into an existing wire without cutting the original. Often used in installing trailer wiring to a tow vehicle
Snap switch
An electrical switch which makes and breaks the circuit with a quick snap. Also called quick make-and-break switch
To take up the drive suddenly when the clutch pedal is released
Snatch tow
A method of recovering a stuck vehicle in which the towing vehicle is in motion before taking up the slack in the tow rope. Use only using special-purpose stretch ropes and specified procedures for this. The kinetic energy is much greater when the velocity is increased.
Abbreviation for synthetic natural gas
A positive click and feel, as when the gears click into place.
A long extension applied to the handle of a wrench in order to increase the leverage in removing a stubborn bolt or nut.
Snipe-nose pliers
A tool used to cut straight, circular, and irregular patterns in sheet metal material; available in various designs for straight, left-or right-hand cut.

Snow and ice control
All activities, including administration, management, planning, and operations, associated with responding to winter road conditions.
Snow and/or ice event
Any weather condition which necessitates snow and ice control operations, such as plowing or sanding.
Recreational vehicle owners who travel to Florida or Arizona during the winter and fly back when the weather warms up at home.
Snow chains
Snow chainsSnow chains

Chains which are wrapped around tires to provide extra traction in snow or ice. They can cause damage to both the tire and the road. They should be used only on short trips while driving at low speeds.

Snow chain switch
Signals the ASR system that snow chains are fitted to the drive wheels
Snow emergency
A declaration by a local government, based on weather and road conditions, that plowing operations will begin and parking restrictions (if any) will be enforced
Snow plan
A document that details specific agency procedures for planning snow and ice control, including equipment, materials, routes, scheduling, use of operators, training, safety, communication, emergency plowing, and clean-up activities
Snow policy
A document that clearly states the principles guiding the scope of an agency’s snow and ice control, the level of service, and what services the public can reasonably expect. It describes agency priorities (roads, routes, and activities) and commencement of operations.
Snow shed
A tunnel-like structure built on the side of a mountain to protect the road from an avalanche.
Snow tire
To slow down a vehicle by activating the brake.

Snubbing Time
Abbreviation for Sulfur Dioxide Acid deposition, commonly called acid rain, occurs when sulfur dioxide and, to a lesser extent, nitrogen oxides (NOx) emissions are transformed in the atmosphere and return to the earth as dry deposition or in rain, fog or snow. Roughly 23 million tons of SO2 is emitted annually in the United States, according to the U.S. EPA. The combustion of natural gas produces virtually no SO2 and, with proper design, far less NOx than combustion of coal or fuel oil.
Soaking time
The time required before a dry-charged battery is ready for use after being filled with acid
Lubricant used to prevent sticking between tire and tube.
Society For Testing Materials
Society of Automotive Engineers


Society of Motor Manufacturers and Traders
(SMMT) An official organization of the British motor industry
The fuel pick up strainer in the fuel tank. The sock is made of saran, so water won’t enter until the sock is entirely engulfed in water.

  1. A hollow part or piece adapted or contrived to receive and hold something.
  2. As a tool, it is usually barrel-shaped with one open end to fit over a nut or bolt and the other open end with a female square drive to accept a drive tool (i.e., usually a ratchet).
Socket bit
A bit for use with socket drive tools
Socket driver
A screwdriver-type handle for use with sockets
Socket Head
A recessed head in which the sides of the recess are parallel to the body axis, into which a wrench fits. The recess is commonly hexagonal or fluted in form. Also designated as internal wrenching head.
Socket head cap screw
Socket head cap screwSocket head cap screw

An externally threaded fastener with unified threads, a cylindrical head with a flat chamfered top surface, knurled cylindrical sides and hexagonal recess, made from alloy steel. Ideal for precision assembly work with close tolerances and applications needing a well tooled appearance.

Socket Head Shoulder Screw
Socket Head Shoulder ScrewSocket Head Shoulder Screw

A hex socket head screw with an enlarged, unthreaded, cylindrical shoulder under the head, the diameter of which serves as the basis for the derivation of the nominal size. For rotation or sliding applications, such as pulley shafts, in punch and die work, or for use as a bearing pin. Also called stripper bolt.

Socket joint
Socket Set Screw
Socket Set ScrewSocket Set Screw

A headless screw threaded the entire length. It has a hexagonal drive at one end. The other end will determine if it is a Cup point socket set screw, Half dog point socket set screw, Oval point socket set screw, Flat point socket set screw, or Cone point socket set screw.

Socket spanner
British term for Socket wrench
Socket wrench
A socket wrench is made up of a Ratchet and a variety of sockets. The ratchet end fits into the sockets. The end is usually one of three common sizes 0.25′ (6.35 mm), 0.375′ (9.5 mm), and 0.5′ (13 mm). The socket (a cylinder) completely covers all the corners of the head of a bolt or nut. Some sockets have six faces while others have twelve.
Sock filter
A foam device which shaped like a cylinder with one end closed and the other open. The open end is secured to a carburetor so that the sock acts like a filter. It is used especially on snowmobiles to keep out the snow.
Sodium-cooled exhaust valve
The exhaust valves of some high-performance engines are filled with sodium to improve the heat dissipation from the valve stem to the valve guide, since the exhaust valve is subject to higher thermal loads than the intake valve
Sodium cooled valve
Sodium-cooled valve
An exhaust valve with a hollow stem that is partially filled with metallic sodium. When the valve gets hot enough (138°C), the sodium melts and moves up and down in the Valve stem. The sodium absorbs heat from the hot Valve head and carries it away to the outer part of the stem and then into the Valve guide in the cylinder head and next to the cylinder head itself. This circulation cools the valve head and thus the valve is allowed to run at a lower temperature.
Sodium Lamp
Sodium lights
A type of high intensity discharge light that has the most lumens per watt of any light source.
Sodium silicate
A grey-white powder soluble in alkali and water, insoluble in alcohol and acid. Used to fireproof textiles, in petroleum refining and corrugated paperboard manufacture, and as an egg preservative. Also referred to as liquid gas, silicate of soda, sodium metasilicate, soluble glass, and water glass.
Sodium-sulfur battery
A new type of battery, with higher energy density than conventional batteries such as the lead-acid battery; developed for use in electric powered vehicles
Sodium tripolyphosphate
A white powder used for water softening and as a food additive and texturizer.
Soft Code
Softening agent
Softening point
The temperature at which a known load will cause the bond failure of a one-square inch sample of cloth bonded to steel (sheer bond). Since softening under heat is progressive, increasing with temperature, it is rarely stated that a product is hard or soft at a certain temperature. The preferred method is to report what weight per square in ch area it can support without failure.
Softening temperature
Soft face hammer
A hammer with a head that is made of a material which will not damage the object being hit. It usually has replaceable screw-on faces made of plastic, nylon, or rubber
Soft paint
A paint fault apparent when the paint surface can be marked easily even after full drying has been allowed; caused by excessive film thickness or, in the case of two-pack paints, an insufficient quantity of catalyst
Soft pedal
The soft, springy feeling detected when the brake pedal is depressed and there is air present in the hydraulic system.
Soft-sided trailer
A trailer with canvas or other fabric walls, which folds compactly to the size and shape of a small trailer whose light weight and low profile result in low wind resistance and fuel consumption

Soft top
A convertible with a roof made of fabric rather than metal
Soft-top trailer
A camping trailer that has a solid box mounted on a chassis. The top portion is made of canvas and unfolds to create one or two wings
Soft trim
A vehicle’s interior decoration, including the upholstery, roof, and door linings. Also called just trim.
Abbreviation for single overhead camshaft where one cam operates both intake and exhaust valves.

Solar car
A lightweight electric vehicle powered by solar generators
Solar cell
Also known as a photovoltaic cell. Device which converts solar radiation directly to electricity.
Solar collector
  1. A heat exchanger that transforms solar radiant energy into heat; typical solar collectors are flat-plate collectors and concentrating collectors
  2. Device used to trap solar radiation, usually using an insulated black surface.
Solar constant
The average amount of solar radiation that reaches the earth’s upper atmosphere on a surface perpendicular to the sun’s rays; equal to 1353 Watts per square metre or 492 Btu per square foot.
Solar cooling
The use of solar thermal energy or solar electricity to power a cooling appliance. There are five basic types of solar cooling technologies: absorption cooling, which can use solar thermal energy to vaporize the refrigerant; desiccant cooling, which can use solar thermal energy to regenerate (dry) the desiccant; vapor compression cooling, which can use solar thermal energy to operate a Rankine-cycle heat engine; and evaporative coolers (swamp coolers), and heat-pumps and air conditioners that can by powered by solar photovoltaic systems.
Solar declination
The apparent angle of the sun north or south of the earth’s equatorial plane. The earth’s rotation on its axis causes a daily change in the declination.
Solar dish
Solar energy
The radiant energy of the sun, which can be converted into other forms of energy, such as heat or electricity.
Solar energy systems
Systems used to collect, convert, and distribute solar energy in forms useful within a business or residence. A passive system uses no additional energy from other sources for the distribution of the solar generated heat. An active system may use blowers, supplementary coils, etc.
Solar generator
A panel-shaped array of photovoltaic cells designed to transform solar radiant energy directly into electric energy; installed on car roofs, they can be used to recharge the batteries of electric-powered cars
Solar heat
Heat created by visible and invisible energy waves from the sun.
Solar Heating
Solar radiation
A general term for the visible and near visible (ultraviolet and near-infrared) electromagnetic radiation that is emitted by the sun. It has a spectral, or wavelength, distribution that corresponds to different energy levels; short wavelength radiation has a higher energy than long-wavelength radiation.
Solar spectrum
The total distribution of electromagnetic radiation emanating from the sun. The different regions of the solar spectrum are described by their wavelength range. The visible region extends from about 390 to 780 nanometres (a nanometre is one billionth of one metre). About 99 percent of solar radiation is contained in a wavelength region from 300 nm (ultraviolet) to 3,000 nm (near-infrared). The combined radiation in the wavelength region from 280 nm to 4,000 nm is called the broadband, or total, solar radiation.
Solar thermal collector
A device designed to receive solar radiation and convert it to thermal energy. Normally, a solar thermal collector includes a frame, glazing, and an absorber, together with appropriate insulation. The heat collected by the solar collector may be used immediately or stored for later use. Solar collectors are used for space heating; domestic hot water heating; and heating swimming pools, hot tubs, or spas.
Solar thermal panels
A system that actively concentrates thermal energy from the sun by means of solar collector panels. The panels typically consist of fat, sun-oriented boxes with transparent covers, containing water tubes of air baffles under a blackened heat absorbent panel. The energy is usually used for space heating, for water heating, and for heating swimming pools.
Solar thermal parabolic dishes
A solar thermal technology that uses a modular mirror system that approximates a parabola and incorporates two-axis tracking to focus the sunlight onto receivers located at the focal point of each dish. The mirror system typically is made from a number of mirror facets, either glass or polymer mirror, or can consist of a single stretched membrane using a polymer mirror. The concentrated sunlight may be used directly by a Stirling, Rankine, or Brayton cycle heat engine at the focal point of the receiver or to heat a working fluid that is piped to a central engine. The primary applications include remote electrification, water pumping, and grid-connected generation.
Solar trough
Solar parabolic trough
  1. To join together using solder
  2. A compound of two or more metals which have a relatively low melting point. Soft solder is an alloy of lead and tin while hard solder is an alloy of copper and zinc. With the application of heat, it is used to join wires or two pieces of metal together.
Joining two pieces of metal together with a lead-tin mixture. Both pieces of metal must be heated to insure proper Adhesion of the melted solder.

Soldering flux
Substance applied to surfaces to be joined by brazing or soldering to keep oxides from forming and to produce joints.
Soldering iron
A tool with a handle attached to a copper or iron tip which is heated, electrically or in a flame, and used to melt solder to make joints
Solder joint
Solder paddle
A tool made of maple or beech, designed for spreading body solder over the surface of a panel
Solder paint
A paste used to prepare the area to be leaded so the body lead will stick to the metal surface; consists of a flux in which powdered lead is held in suspension
  1. An electrically operated magnetic device used to operate some unit. A movable iron core is placed inside a coil of wire which moves because of magnetic attraction when electric current is fed to the Coil. When current flows through the Coil, the core will attempt to center itself in the coil. In so doing, the core will exert considerable force on anything it is connected to.
  2. An electromagnetic valve or relay that opens or closes to regulate hydraulic pressure in an anti-lock brake system.
Solenoid starter switch
A solenoid-operated starter motor switch
Solenoid Vacuum Valve Assembly
Solenoid valve
  1. A valve actuated electrically by means of an electromagnet, or solenoid
  2. Valve made to work by magnetic action through an electrically energized coil.
  3. Electromagnet with a moving core. It serves as a valve or operates a valve.
Solenoid vent valve
(SVV) energized by ignition switch to control fuel vapor flow to the canister. When the ignition is off, the valve is open
Sole proprietorship
Business owned entirely by one person
  1. Anything which does not have a tendency to flow (such as vapor or fluid).
  2. Unventilated brake discs.
Solid brake disc
A brake disc that is solid metal between its friction surfaces
Solid brake drum
A drum made entirely of cast iron.
Solid brake rotor
A rotor with solid metal between its friction surfaces.
Solid Deck Pallet
A pallet constructed with no spacing between deck boards.
Solid disc wheel
Solid fuel heating
The use of solid natural resources such as wood or coal to provide heat.
Solid height
The height of a coil spring when it is totally compressed to the pont at which each coil touches the adjacent coil.
To become solid, compact, or hard
Solid injection
System used in full diesel and semi-diesel where fuel in fluid state is injected into cylinder rather than a mixture of air and fuel drawn from a carburetor

A motorcycle with a solid-mounted engine bolted directly to the frame tubes.
Solid oxide fuel cell
(SOFC) A type of fuel cell in which the electrolyte is a solid, nonporous metal oxide, typically ZrO2 doped with Y2O3, and O2- is transported from the cathode to the anode. Any carbon monoxide (CO) in the Reformate gas is oxidized to carbon dioxide (CO2) at the anode.
Solid paint
Paint of one uniform color, not metallic.
Solid phase pressure forming
A special type of thermoforming of polypropylene sheeting
Solid propellant
A propellant in pellet form, used to inflate air bags
Solid rivet
Solid rivetSolid rivet

A small metal fastener having no internal cavity, made of malleable material. Once the rivet is inserted in a hole, the free end is peened to secure it.

  1. The ingredients (Pigments and binders) of the paint that remain on the surface after the Solvents evaporate.
  2. Industrial tires made without an air chamber.
  3. Non-volatile ingredients in an adhesive, coating or sealer. Same as solids content.
Solids in Bulk cargo
Truck that contains commodities that are not packaged, and are generally carried loose.
Solid state
Electronic device or assembly that does not have moving parts
Solid-state controlled ice maker
Includes controls for ice maker that uses components made of semiconductors.
Solid state controller
An electronic controller which uses transistors, diodes, and other semiconductor devices.
Solid-state electronic relays
Solid-state ignition
Solid state ignition system
(SSI) a system used by Ford
Solid tire
A solid rubber tire that is not inflated by air. The opposite is Pneumatic tire. Solid tires are used on slow-moving wheels (i.e., wheelchairs, buggies, children’s wagons, etc.).

Solo seat
A motorcycle saddle designed for just the operator.
Matter or compounds capable of dissolving into a solution.
Soluble anode
Positive electrode of a galvanic cell at which metal ions pass into solution
Soluble Organic Fraction
(SOF) The organic fraction of diesel particulates. SOF includes heavy hydrocarbons derived from the fuel and from the engine lubricating oil. The term soluble originates from the analytical method used to measure SOF which is based on extraction of particulate matter samples using organic solvents.
  1. A single, homogeneous liquid, solid, or gas phase that is a mixture in which the components (liquid, gas, solid, or combination thereof) are distributed uniformly.
  2. A liquid which has another liquid or solid completely dissolved in it. A lithium bromide water solution, commonly used in absorption Systems, is water with a quantity of lithium bromide dissolved in it. ‘Strong’ and weak solutions are those with respectively high and low concentrations of another liquid or solid.
Solution annealed
A process of heating and removing carbide precipitants (carbon that has broken loose from its stainless steel solution) by heating a finished fastener to over 1000°C and cooling it quickly, usually in water, so carbon content goes back into the stainless solution. Also called carbide solution annealed
Solution pressure
A measure of the tendency of hydrogen, metals, and certain non-metals to pass into solution as ions
  1. A fluid that dilutes, liquefies, or dilutes another liquid or solid. Solvents include Thinners, Reducers and cleaners. Examples Alcohol thins shellac; gasoline dissolves grease.
  2. Any liquid which will dissolve another substance. The solvent power of a liquid is specific; that is, it will dissolve some substances but not others. Solvents are often of a volatile nature and do not remain in a set or cured adhesive, coating, or sealer film. Their main purpose in adhesives, coatings, or sealers is to convert the solid portion into a more fluid state so that it can be easily applied.
Solvent pop
Small bumps in a paint film which, under close inspection, can be seen to have small holes in the top; caused by excessive film depth being applied in one coat, preventing the thinners from escaping properly
Solvent popping
Blister that form on the paint film, caused by trapped solvents
Solvent reactivation
To restore the surface tackiness in a dry adhesive film with a suitable solvent.
Solvent resistance
Ability of an adhesive, coating, or sealer to withstand total immersion in a given solution without losing its original properties.
SomersetClick image for books on
Buick Somerset

A model of automobile manufactured by the Buick division of General Motors from 1985-1987

  1. Calculated sound loudness rating.
  2. A measurement of the noise level of a fan. The lower the sone rating, the lower the noise level.
Sonic idling
A system developed by Ford, for a fixed jet carburetor which uses air at the speed of sound to atomize fuel supplied by the idling circuit; makes idling smoother and reduces exhaust pollution. Also called sonic throttling
Sonic throttling
A system developed by Ford, for a fixed jet carburetor which uses air at the speed of sound to atomize fuel supplied by the idling circuit; makes idling smoother and reduces exhaust pollution. Also called sonic idling
A diagnostic tool used to listen for noises in engines and identify trouble spots such as faulty valves, worn gears and water pump, bearing knock, damaged gaskets, or piston slap. Also called a Mechanic’s stethoscope
Sooted plug
A carbon-fouled spark plug
Sooty plug
A carbon-fouled spark plug
Sounding pipe
A pipe leading to the bottom of an oil or water tank, for guiding a sounding tape or jointed rod when measuring the depth of liquid in the tank
Sound absorption
The weight and space restrictions of modern cars call for sound absorption using thin-walled materials, whose thickness is small in relation to the wave length of the sound to be absorbed
Sound level
The sound pressure level (in decibels) at a point in a sound field, averaged over the audible frequency range and over a time interval, with a frequency weighting and time interval specified by the American National Standard Association.
Sound metal
An intact metal panel not substantially weakened by rust that provides a basis, for example, for welding on repair panels
Soundproofing material
Any material used to deaden the sound from surfaces which transmit or generate noise; (e.g., felt lining on the underside of a hood).

Sound tracer
Instrument which helps locate sources of sound.
Sound walls
Concrete block or concrete panel walls specifically designed to reduce road sounds outside of the right-of-way.
Souped up
A vehicle is souped up when it is tuned to produce the maximum amount of power.
Hopping up or increasing engine performance through various modifications.
Source lamp
Source Leasing
Sour gas
Natural gas that contains hydrogen sulfide (H2S). Contrast Sweet gas
South pole
The magnetic pole in a magnet toward which the lines of force emanate; travel is from North to South pole.

South pole, magnetic
The part of a magnet into which magnetic flux lines flow.
Symbol for oxides of sulfur
Space frame
A type of frame construction which has high rigidity for its low weight. It is used with some racing and low production cars. It is made up of several lengths of tubing welded into a strong, light web-like structure to which the engine, suspension, and other components are attached.
  1. A component which moves two items further apart. Sometimes it is just a washer and at others it is a metal or plastic cylinder or a block of rubber or plastic.
  2. A band on demountable rims which fits between two rims in dual mounting to provide clearance between the duals.
  3. A circular metal plate having a bolt hole circle and center bore and fitting between the faces of disc wheels to provide additional dual clearance.
  4. Pieces designed to prevent crushing of sandwich-type and other lightweight structural materials at fastening points. Sometimes called inserts.
Spacer entry EGR system
Exhaust gases are routed directly from the exhaust manifold through a stainless steel tube to the carburetor base
Spacer plate
Spacer ring
Spacer washer
A sheet of metal or other material placed between two surfaces to reduce clearance or to provide a better surface for a fastener
Space saver spare
A spare wheel and tire which is much smaller than the regular tires and can be used to replace a flat tire. However, the spare is limited in speed as well as performance. The British call it a tempa spare wheel. Also called Collapsible spare tire.

Space-saving spare wheel
Space saver wheel
Space saving tire
A Spare tire which is smaller than normal and has limited use only when a flat tire occurs.
Space wagon
A vehicle category introduced in the USA in 1983 with the Chrysler Voyager, and in Europe at the end of the 1980s with the Renault Espace; a multi-purpose vehicle for everyday and recreational use that combines the handling and luxury of a sedan with the space and headroom of a van; usually with three rows of seats for at least six people and with a sliding door on the side
Spade Screws
A threaded, round body with a finger tightening projection. (Regular Offset or Bent). Primarily used in places needed for frequent adjustments or for knock-down assemblies.
Spade terminal
A terminal used to connect a wire to a screw or stud terminal. The spade the has two forked ends, either straight or with upturned tips. They are more convenient to install than ring term, but slight less secure for rugged applications. Comes in soldered and unsoldered versions
A flaking of the surface of a bearing
Crystal structure on hot-dip galvanized metals
Although a British term for a wrench, it is also used for many bicycle tools in the U.S.A. and Canada.

Spanner Screws
Special unslotted screws surface, in Round undrilled, Flat drilled and others, that require a special wrench.
Spanner Wrenches
Tools used to turn and tighten spanner screws.
Spare part
A replacement part, either available from a dealer or carried with the vehicle (like bulbs, fuses, plugs, etc.)
Spares car
Spare tire
An extra wheel and tire assembly which is stored in the vehicle in the event of a flat tire.

Spare tire carrier
The horizontal rack near the rear axles, below the loading area of light commercial vehicles where the spare wheel is usually mounted
Spare wheel
Spare wheel well
An indentation in a flat trunk floor that houses the spare wheel in a horizontal position
The bridging or jumping of a gap between two electrodes by a current of electricity. One of the essential factors in a Combustion engine (Fuel, Air, Proper proportion of mixture, compression, timing, Spark).

Spark advance
A device which causes the spark plug to fire earlier by altering the position of the distributor’s breaker points in relation to the Distributor shaft.

Spark Advance Control
Spark air gap
The gap between the electrodes of a spark plug.

Spark angle
Spark-angle map
Spark arrester
A device which hinders flames from exiting the exhaust pipe.
Spark breakaway
The end of spark duration
Spark control
Spark control computer
(SCC) electronic control unit with electronic spark timing
Spark current
Current that flows across the electrodes of a spark gap at a particular point in time
Spark delay valve
(SDV) a valve in the vacuum advance hose that delays the vacuum to the vacuum advance unit during rapid acceleration from idle or from speeds below 15 mph, and cuts off spark advance immediately on deceleration. Has an internal sintered orifice to slow air in one direction, a check valve for free air flow in the opposite direction and a filter
Spark discharge voltage
Spark duration
  1. The burning time of the arc following the initial flashover between the spark plug electrodes until the residual energy decays
  2. The length of time measured in milliseconds that the spark is established across the spark plug gap
Spark gap
The space between the center and side electrode tips on a spark plug.


Spark gap coil tester
A tester providing a spark gap or neon tube to provide a comparison for the coil being tested. The coil to be tested is connected to the spark gap of the tester, and the length of the spark it produces is measured; a good coil is used as a standard of performance
Spark head
Displayed as a firing spike on an oscilloscope pattern
Spark ignition
An ignition initiated by an electric spark in a spark ignition engine.

Spark ignition angle
Spark ignition engine
(SI engine) In contrast with a diesel engine (which does not use a spark plug), a spark ignition engine uses a spark plug to ignite the fuel/air mixture.
Spark knock
Spark map
Spark method
Spark plug
Spark plugSpark plug

A device containing two electrodes across which electricity jumps to produce a spark to fire the fuel charge. The center electrode is insulated from the spark plug shell by means of a molded insulator resembling Porcelain. The side electrode protrudes from the bottom edge of the spark plug shell and is so positioned that there is a gap between it and the center electrode.

Spark plug body
Spark plug boot
A molded rubber or plastic insulator at the end of the spark plug wire and which fits over a spark plug terminal
Spark plug boot puller
A special automotive tool for the safe removal and installation of spark plug boots
Spark plug brush
A hard, compact brush for removing carbon from spark plug electrodes
Spark plug cable
British term for Spark plug wire
Spark plug cable cover strip
The connecting system that integrates the spark plug connectors, spark plug leads, distributor cap, distributor connector, high-voltage cable, and ignition coil connector
Spark plug cable loom
Typically, a T-shaped and sometimes chrome-plated steel holder with cable guide holes and plastic inserts; keeps cables neatly in place and eliminates ignition leakage
Spark plug cable separator
Typically, a T-shaped and sometimes chrome-plated steel holder with cable guide holes and plastic inserts; keeps cables neatly in place and eliminates ignition leakage
Spark plug cable marker
A numbered snap-on C-clip which identifies the firing order
Spark plug cap
The device on the end of the high tension wire coming from the coil and mounted on the spark plug. Also called Plug cap
Spark plug condition
A visual appearance of the spark plug electrodes and insulator
Spark plug electrode
The two electrodes in a spark plug are the center electrode and the side (or ground) electrode
Spark plug gap
The space between the center and side electrodes of a spark plug across which the spark must jump to ignite the air-fuel mixture in the combustion chamber.
Spark plug gauge
A tool used for checking spark plug gaps; usually with metal feeler blades or calibrated wire feelers (the wire-type is preferred over the blade type). It often includes an electrode adjusting tool for altering the gap between the electrodes
Spark plug heat range
The ability of the spark plug to dissipate heat.
Spark plug insert tap
A tool used to enlarge and tap new threads in damaged spark plug holes in order to accept spark plug inserts
Spark plug insulator
A highly stressed part of the spark plug, usually made of alumina ceramic, which serves to insulate the center electrode and the terminal stud from the shell; its material must have high dielectric, mechanical and thermal strength as well as good thermal conductivity
Spark plug lead
Spark plug pliers
A pliers-like tool with specially shaped jaws to securely grip spark plug boots for removal and installation, and insulated handles for a shock-proof grip
Spark plug shell
The metal body of the spark plug which encloses the lower part of the insulator
Spark plug socket
A tool used to remove or install spark plugs. It is a metal cylinder with a rubber lining that fits over the exposed end of the spark plug to make it easy to remove the plug without damaging its porcelain surface.

Spark plug spanner
Spark plug tester
  1. A screwdriver with a bulb inside the handle, which lights up if a spark is present when the blade is touched against the outside insulation of the spark plug wire.
  2. A large instrument into which a spark plug is screwed and a high tension wire is secured to the top of the plug to duplicate an ignition system. By looking into the sight glass, you can see how well the spark plug is firing.
Spark plug whiskering
Spark plug wire
A high-voltage wire (either copper core or carbon core) with thick insulation. It comes from the distributor to the spark plug. Also called Ignition cable
Spark plug wire cover strip
The connecting system that integrates the spark plug connectors, spark plug leads, distributor cap, distributor connector, high-voltage wire, and ignition coil connector
Spark plug wire loom
Typically, a T-shaped and sometimes chrome-plated steel holder with wire guide holes and plastic inserts; keeps wires neatly in place and eliminates ignition leakage
Spark plug wire separator
Typically, a T-shaped and sometimes chrome-plated steel holder with wire guide holes and plastic inserts; keeps wires neatly in place and eliminates ignition leakage
Spark plug wire marker
A numbered snap-on C-clip which identifies the firing order
Spark plug wrench
A tool for removing and installing spark plugs. It comes in a variety of shapes, e.g., with swivel or T-handle, and many have rubber inserts to prevent damage to the fragile insulating porcelain
Spark position
The position of the spark gap in the combustion chamber.

Spark rate
The spark rate per minute in a spark ignition engine is the number of cylinders multiplied by half the engine speed
Spark retard
The action of changing the ignition timing so that the spark occurs after what is specified by the manufacturer.

Spark timing
Spark timing system
Spark voltage
  1. The voltage required to maintain the spark after reduction of the firing voltage.
  2. The voltage measured at the electrodes of a spark gap at a particular point in time.
Spar-type frame
Sparks produced during the welding process; more pronounced if the welding parameters are not correctly set or if impurities are present on the welded area
Abbreviation for speed, as in 4-spd. transmission.
SPD compatible
A Shimano developed bolt pattern drilled into the sole of cycling shoes resembles two parallel, identically sized slots into which an SPD pedal cleat is attached.
SPD-R compatible
A newer style of Shimano’s pedal bolt pattern. SPD-R compatible shoes are drilled differently from the original SPD system. The drilling for an SPD-R cleat has a long slot on the right side of the sole with three bolt holes. Next to this long slot is a shorter slot to the left with one bolt hole.
A sound device which contains a magnet and a relatively large vibrating diaphragm which translates electrical impulses into sound vibrations.

Speaker grille
A covering over the speaker which protects the sensitive diaphragm and yet permits the maximum output of sound.
Speaker enclosure
The housing for the speaker (i.e., its box) which may enhance the output of sound.
Abbreviation for special, as in spec. paint colors or for Specification
Special body
A body not supplied by the car manufacturer or by an approved body supplier in the case of manufacturers that do not build their own bodies, but rather by an independent coachbuilder who produces a body different from the standard body. A One-off body refers specifically to a body of which only one example is made, whereas in general, special or coachbuilt bodies may be produced in small-scale series
Special collector
An evacuated tube collector or a concentrating (focusing) collector. Special collectors operate in the temperature range from just above ambient temperature (low concentration for pool heating) to several hundred degrees Fahrenheit (high concentration for air conditioning and specialized industrial processes).
Special Import Measures Act
(SIMA) Helps to protect Canadian producers from harm or injury caused by the dumping of goods into Canada by foreign exporters or the subsidizing of goods by foreign governments.
Special ledge
(SL) A safety bead seat contour mainly used on American passenger cars
Special mileage tire
A tire manufactured with an extra layer of rubber between the cord body and the original tread design. This extra layer is designed for the purpose of recutting and regrooving, and is specifically labeled as a special mileage commercial tire. Also called regrooveable tire.
Special naphthas
All finished products within the Naphtha boiling range that are used as paint thinners, cleaners, or solvents. These products are refined to a specified flash point. Special naphthas include all commercial hexane and cleaning solvents conforming to ASTM Specification D1836 and D484, respectively. Naphthas to be blended or marketed as motor gasoline or aviation gasoline, or that are to be used as petrochemical and synthetic natural gas (SNG) feedstocks are excluded.
Special services
A category that describes plants which add value to automotive parts manufactured by others by using process such as painting, plating, heat treatment, etc.
Specialty repair shop
Retail outlet which offers specialized vehicle products and service.
Specific activity
The conversion rate of a given catalytic converter per unit volume; it is desirable to have a high specific activity, i.e., a small but efficient converter
  1. A list of the measurements of each component of a vehicle and the requirements for proper installation. The size, description, or part numbers for various items needed to maintain or repair a vehicle.
  2. The properties of a product within certain parameters such as quantity, temperature, pressure, humidity, specific gravity, purity, pour point, viscosity, and shape. For instance if you contracted to buy a full bucket of water, and I gave you a full bucket of ice cubes, when they melted, you would not have a full bucket of liquid. Thus the need for correct specifications. This applies to crude oil and petroleum products including gasoline and motor oil.
Specific fuel consumption
(SFC) The amount of fuel consumed by an engine for each unit of energy produced; measured in kilograms-per-megajoule or kilograms-per-kilowatt-hour or pounds-per-bhp-hour

Specific gravity

  1. Weight of a liquid compared to water at 15°C, which is assigned the value of 1.0.
  2. The relative weight of liquid (battery electrolyte) as compared to the weight of an equal volume of water.
  3. Gasoline has a specific gravity of 0.720 which means that it weighs 0.72 times as much as water, or it is 72 percent of the weight of water. Most gasolines weigh about 6.2 pounds per US gallon (0.72 kg per litre).
  4. A more appropriate term is Relative density
Specific heat
  1. In physics, the number of calories required to raise the temperature of 1 gram of a substance 1°C or the number of BTUs per pound per degree F. In air conditioners, the quantity of heat required to change the temperature of one pound of a substance by 1°F.
  2. Ratio of quantity of heat required to raise temperature of a body 1 degree to that required to raise temperature of equal mass of water 1 degree.
Specific heat capacity
(SHC) The quantity of heat which unit of mass of a substance requires to raise its temperature by one degree.
Specific power
(kW/kg). A measure of the energy generating or storage potential of a system per unit of weight.
Specific speed
An index which provides information on the general profile or shape of the impeller of a pump. The specific speed is the speed in revolutions per minute at which an impeller would run if reduced in size to deliver one gallon per minute against a total head of one foot; impellers for high heads usually have low specific speeds and impellers for low heads usually have high specific speeds
Specific volume
Volume per unit mass of a substance.
Abbreviation for Specifications.
Spec series
A general describing several of the racing series where the rules for the series specify a certain chassis, or engine that the racers are required to use. Thus, the reference to spec. Examples of a spec series is the Formula Atlantic series, where all the cars must use the Toyota engine.
Spec. Sheet
Specification Sheet. Detailed information of a product including, tests, color, odor, specific gravity, bacterial strains, size, shape, texture, other major ingredients, etc.
Spectacle frame
A large casting extending outboard from the main hull for supporting for the ends of the propeller shafts in a multi-screw ship
Specular finish
A mirror-like finish of high reflectivity
Specular gloss
A mirror-like finish of high reflectivity
Specular reflectors
Specular reflectors have mirrorlike characteristics. The most common materials used for ballasts, the devices that turn on and operate Fluorescent tubes, are aluminum and silver. Silver has the highest reflectivity; aluminum has the lowest cost. The materials and shape of the reflector are designed to reduce absorption of light within the fixture while delivering light in the desired angular pattern. Adding (or retrofitting) specular reflectors to an existing light fixture is frequently implemented as a conservation measure.
Speech synthesizer
An electronic device which simulates speech to warn the driver of something wrong (such as an unclosed door).

  1. The average rate at which an object is traveling. Measured as a relationship of distance per time — e.g., metres per second (m/s), kilometres per hour (kph or km/h), feet per second (ft/sec.), miles per hour (mph), or revolutions per minute (rpm).
  2. The number of gears in a transmission.
The top speed a vehicle can attain as determined by engine power, engine governed speed, gross weight, driveline efficiency, air resistance, grade of road, and load.
Speed Actuator
Speed adjustment
Speed brace
A drive handle in the shape of a crank; appropriate for fast operation but not having sufficient leverage for large nuts and bolts
Speed category
Speed changer
A device for adjusting the speed governing system to change the engine speed.
Speed circuit
Speed control
Another name for cruise control.

Speed Control Motor
Speed control vacuum advance
A system which cuts off vacuum ignition advance when a car is cruising at low speeds, typically under 35 mph; for this purpose, a solenoid-operated valve is hooked into the distributor advance vacuum line, which is governed by a speed-dependent signal from a switch mounted on the transmission
Speed direct
Speed direct injection
Speed drift
A very gradual deviation of the governed speed from the desired speed.
Speed Drives
Speed droop
Governor control of engine speed variation from no load to full load. The change in a governor’s rotating speed which causes the governor’s output shaft (fuel-control rod) to move from its full-open throttle position to its full-closed throttle position or vice versa.
A drive handle in the shape of a crank; appropriate for fast operation but not having sufficient leverage for large nuts and bolts
Speed limit
The maximum speed that the law allows on a particular road. A speed limit is set for various factors such as school and playground zones; safety in negotiating curves and off ramps; national limits; fuel conservation; divided highways vs two-way traffic; construction zones; and city ordinances.
Speed limiter
Speed nut
  1. A self-locking device used especially to secure sheet metal screws; consists of a small steel plate with a hole and two arched prongs that engage with the screw thread; used extensively to attach plastic parts to a steel car body
  2. Spring-steel clips used to hold floating drums and rotors in place during vehicle assembly.
Abbreviation for Speedometer.
Speedo cable
Instrument usually found on the dashboard which is used to determine forward speed of a vehicle in kilometres per hour or miles per hour.

Speedometer cable
A long specially constructed wire inside a Housing. The one end of the speedometer cable is inserted into the back of the Speedometer head and the other end is usually attached to the transmission. When the speedometer Needle moves erratically or the cable makes noise, the cable needs to be lubricated with specially formulated Compound. Oil will cause it to stick.
Speedometer drive cable
Speedometer head
The instrument cluster which displays the road speed.
Speed rating
The maximum driving speed for which a tire is designed, indicated by a letter in the tire designation on the sidewall. The speed rating evolved gradually and is thus not directly proportional to the alphabetical order.

P = up to 150 km/h (95 mph)
Q = up to 160 km/h (100 mph)
R = up to 170 km/h (105 mph)
S = up to 180 km/h (113 mph)
T = up to 190 km/h (118 mph)
U = up to 200 km/h (125 mph)
H = up to 210 km/h (130 mph) also called high speed thus the ‘H’
V = up to 240 km/h (150 mph) also called very high speed thus the ‘V’
W = up to 270 km/h (168 mph)
Y = up to 300 km/h (186 mph)
Z = over 300 km/h (186 mph)
Speed ratio
The ratio of the speed of the driving member of a mechanical drive to the speed of the driven member
Speed screw
Speed-sensitive steering
A type of power-assisted steering which is light at low speeds and increasingly heavier at higher speeds, giving the driver more feel
Speed-sensitive wiper system
A system which increases blade pressure on the windshield as the car increases speed
Speed sensor
A detection device that measures the speed of a wheel or drive axle and sends the information in the form of a analog voltage signal to the ECU.

Speed stabilizer
A fast, sporty car model
Speed symbol
Speed-time Curve
Speed traction
Speed traction control
Specialized sport run on short, oval dirt tracks with four riders from two teams in each race.
Impure zinc containing about three percent lead and other impurities
Spent gas
The gases burnt during the previous firing cycle that remain in the combustion chamber of a two-stroke engine after the charge changing process has been completed and the ports have been closed by the piston. An excessive proportion of spent gas in the cylinder weakens the mixture available for combustion
Spherulitic graphite cast-iron
Cast iron in which the graphite formed during solidification is induced to form as insolated spheroidal particles rather than flakes.
Abbreviation for single point fuel injection
Spherical combustion chamber
The combustion chamber of an internal combustion engine equipped with reciprocating pistons is ideally very compact in design, i.e., without gaps, grooves, edges, etc.; the most favorable design would thus be a sphere but the valves of a four-stroke engine make this impossible. The combustion chamber in diesel engines, however, is located in the piston crown, where it is in fact spherical
  1. Abbreviation for Single point injection
  2. Abbreviation for Serial Peripheral Interface
A gearbox splitter which provides a second range of gears

  1. On a bicycle, the multi-armed piece to which the Chainwheels are bolted, usually welded to or part of the right crankarm.
  2. A four arm piece on a Constant velocity joint.
  3. A central crosspiece linking the two yokes of a universal joint.
  4. A cross-shaped wheel wrench with a different-sized box socket head on each of the four legs.
  5. A Wheel spider
  6. A type of sport vehicle. In the early 1900s it meant a light two-seater car. In the 1950s the word was revived by some Italian manufacturers for an open two seater sports car. Also spelled spyder.
SpiderClick image for books on

A model of automobile from Alfa-Romeo

Spider filter wrench
Spider wrenchSpider wrench

Adjustable filter wrench that has two clamping legs driven by a gear mechanism for maximum range and gripping ability.

Spider gear
A small gear (usually in a set of two to four gears) mounted on a shaft pinned to the Differential case. They mesh with the Bevel gear on the ends of the axles and drive them.

A short, cylindrical projection on one part designed to fit into a hole in another part, for location or retaining purposes (as for road wheels)
Spigot bearing
A British term for Pilot bearing. A small bearing in the center of the flywheel end of the crankshaft, which carries the forward end of the clutch shaft
Spigot mounting
Unlike stud-mounted wheels, spigot-mounted wheels incorporate a center hole in the wheel disc which is machined to provide a close-tolerance fit on the hub spigot for location
Spillover point
The location of the main circuit discharge in the venturi, which is always higher than the fuel level in the bowl so fuel won’t run into the venturi when it shouldn’t. When the spillover begins is determined by the size of the venturi and by the displacement of the engine pulling air through the carburetor. Also called Pullover point
To shape sheet metal by forcing it against a form as it revolves.

  1. The machined shaft upon which the inside Races of the front wheel bearings rest. The spindle is an integral part of the steering knuckle.
  2. Another term for an axle, such as a pedal axle or a bottom bracket axle.
  3. That part of the front suspension system about which a front wheel rotates.
  4. A shaft or pin about which another part rotates
Spindle cap
A small metal cap on the front wheel bearing
Spine frame
A frame with a single main structural member from which the engine is suspended
Spin galvanizing
A hot dip galvanizing process for small objects. The objects are immersed into the molten zinc in a perforated basket which, once the coating forms, is centrifuged at high speed so that the spinning action throws off the surplus zinc and ensures a clean profile
Spin imbalance
A knock-off/on nut for central-locking wheels. Originally developed by the British company Rudge-Whitworth to enable racing car wheels to be changed quickly by knocking the nut on and off with a soft-headed hammer; the wheel is positioned by matching tapered faces within the wheel center and on its hub, the splines enabling driving or braking forces to be transmitted from hub to wheel; the spinner is a self-tightening nut with a left-hand thread for RH-side wheels and a right-hand thread for LH-side wheels; modern cars use large hexagon nuts.

Spinner handle
A screwdriver-type handle for use with sockets, used to quickly tighten and loosen fasteners
Spinner knob
Spinner knobSpinner knob

A device which is attached to a steering wheel to allow disabled people to steer a vehicle by the use of the knob.

A race car that spins around due to being tapped, racing too close to another car, or clipping another while attempting a pass.
Spin regulation
Spin Sensors
Spiral bevel gear
A Ring and pinion setup widely used in automobile differentials. The teeth of both the ring and the Pinion are tapered and are cut on a spiral so that they are at an angle to the center line of the pinion shaft.

Spiral casing
Spiral-type glow plug
A glow plug having an exposed coil with a high number of turns
Spiral wrapped pin
A tube-like pin that is made by rolling a sheet of metal tightly together. Used as a Shear pin.
SpiritClick image for books on

An automobile manufactured by AMC

Spirit level
A tool for testing if a surface is level (or vertical) using a glass tube containing an air bubble
Abbreviation for Safety Priority Index System
Abbreviation for speakers, as in dual rear spkrs.
Abbreviation for Smoke Puff Limiter
Ford Ranger’s term for a Stepside truck.

Splash and pressure
Splash and pressure system
Splash apron
Splashed graphics
A custom paintwork resembling paint drops and splashes on the body which look as if a can of paint had been spilled over the car; also available as stickers
Splash guard
Splash lubrication
Oil from the crankshaft journals, under pressure from the oil pump, is splashed onto the cylinder bores and piston pins to provide lubrication
Splash panel
A vertical closing panel mounted inside the wheel arch ahead of the rear edge of the front fender and/or hinge area to protect these areas from splash water and road dirt
Splash shield
A removable device found on disc brakes to keep water, snow, and dirt from fouling the brakes. It also sends cool air to the inner side of the disc to help in heat dissipation.
Splash system
Splash system, oiling
Method of lubricating moving parts by agitating or splashing oil in the crankcase.
Splash zone
The sections of a car body subject to extreme corrosion loads due to water splash
Splayed crankpins
The slight spreading apart of a crankpin in a V-type engine so that each rod has its own crankpin; this reduces vibration in some V-6 engines that have a 90° angle between the banks
Splayed spring
A design in which the leaf springs are placed at other than an 90° to the axle
  1. A thin, narrow strip of metal
  2. In order to secure one object on a shaft, longitudinal grooves or splines are cut all around the shaft with matching grooves in the object. In this way the object slides on the shaft for installation so that both the object and the shaft rotate together.
  3. Raised portions of a shaft which fit into corresponding grooves in a pulley or some sliding member. They can either permit end movement or can be used as permanent fastening.
Splined bottom bracket
Shimano’s uniquely oversized, splined bottom bracket spindle that is compatible only with newer style Shimano cranksets.
Splined hub
The hub of a driven plate in a clutch which is splined so that it can move along the gearbox input shaft
Splined joint
A Joint between two parts in which each part has a series of Splines cut along the contact area. The splines on each part slide into the grooves between the splines on the other part.
Splined shaft
A shaft having multiple grooves, or Keyseats, cut around its circumference.
Spline joint
Two mating parts that have a series of splines around their circumferences, one inner and one outer, to provide a longitudinally movable joint without any circumferential motion
Spline Nut
A nut having external splines or ribs which hold it in place when forced into a hole of slightly smaller diameter.
Spline Socket
A recessed socket in the head of a bolt or screw to develop greater torque or driving ease without rounding the recess.
Split bearing
Split bearing attachment
Split bench seat
A front seat arrangement in which the left side is independent from the right side. While a Bucket seat is shaped for an individual, split bench seats can still hold three people. Most are split 60/40 where the smaller portion is for the driver. It avoids the disadvantage of the bench seat in that the driver can position his seat differently from the passenger.
Split brake system
A service brake system having two or more separate fluid, electrical, mechanical or other circuits which upon failure in any circuit retains full or partial brake actuating capability.
Split braking
Split braking system
Split collar

Split crankcase
A crankcase of an engine which is divided horizontally near the center of the crankcase.
Split electrode spark plug
A spark plug with a V-shaped side electrode
Split folding rear seats
Rear seats which may be folded down in two sections, thus combining some extra luggage space with the possibility of a passenger sitting in the back of the car
Split-friction road surfaces
Differing road surfaces (such as ice and tarmac) offering differing tire adhesion
Split hydraulic brake system
Service brake system with two separate hydraulic circuits to provide braking action in one circuit if other one fails
Split Lens
Split-lit-type rear main seal bearing
A two-piece neoprene seal; easier to install and has less friction than a rope-type main seal
Split loom
Flexible, corrugated conduit used to bundle wires into a harness
Split manifold
An exhaust manifold that has a longitudinal Baffle placed near its center. An exhaust pipe leads out of each half.
Split-phase motor
Motor with two stator windings. Both windings are in use while starting. One is disconnected by centrifugal switch after motor attains speed. Motor then operates on other winding only.
Split pin
A metal pin for securing a nut or rod, whose ends are bent backwards after insertion.

Split point
The pressure at which a brake proportioning valve begins to limit hydraulic pressure to the rear brakes.
Split propshaft
Split rear axle housing
A rear axle housing made up of several pieces and bolted together. The housing must be split apart to remove the differential. Compare Banjo rear axle housing
Split rear seats
Rear seats which may be folded down in two sections, thus combining some extra luggage space with the possibility of a passenger sitting in the back of the car
Split rim
A rim which is made of two or three pieces and uses a demountable flange.
Split ring lock washer
Split ring lock washerSplit ring lock washer

A coiled, hardened, split circular washer with a slightly trapezoidal wire section.

Split Rivet
A small rivet having a split end for securing by spreading the ends.
Split screen
A divided windshield on the original Morris Minor
Split single
A two-stroke engine with two pistons that share a single combustion chamber
Split skirt
Split skirtSplit skirt

The piston skirt is manufactured to be either partially or completely split. When the piston warms and begins to expand, the split closes instead of binding in the cylinder.

Split skirt piston
A precursor of the modern solid piston skirt, with a narrow slot in one side of the piston to allow for expansion
Split spray
An incorrect setup of a spray gun, giving a spray pattern that is heavy at the top and bottom but narrow in the middle
Split system
Refrigeration or air conditioning installation which places the condensing unit outside or away from the evaporator. Also applicable to heat pump installations.

Split-system master cylinder
Splitting chisel
An extremely flat chisel used for body work and panel beating
Splitting lanes
The action of straddling the center line between two lanes of traffic so that following vehicles cannot pass on either side. This is a discourteous procedure unless it is the action of a police officer to slow down traffic because of an accident some distance ahead.
Splitting the cases
Taking the motorcycle transmission cases apart to repair the motor.
Splitting tool
Split type
Split washer
The original VW Beetle with a two-part rear window split vertically; produced up to 1953
An aerodynamic wing-shaped device attached to a vehicle (usually under the front bumper or on the decklid) to either reduce Drag or induce Downforce on the vehicle. So called because it spoils the normal flow of air over or under the vehicle.

  1. One of several wires used to hold the hub in the center of a wheel rim and to transfer the load from the perimeter of the wheel to the hub and on to the frame.
  2. Generally stainless steel, the spokes connect the hub to the rim on a wheel and provide structure. Most wheels have the spokes pass through holes in the hubs and then thread into spoke nipples seated in the rim. Tightening the spoke nipples creates tension in the wheel to maintain structural integrity and keep the wheel true.
Spoke assembly

Spoke steel type
Spoke wheel
A styled, cast or forged alloy wheel with a wheel spider which incorporates a spoke design. Spoke wheels can be distinguished according to the respective number of spokes; many alloy spoke-type wheels, however, have a wheel spider with 28, 30, 32, or 34 spokes which are arranged in different angles and in a criss-cross pattern these are referred to as cross-spoke wheels.

Spoke wrench
A tool for securing or removing spokes by turning the Nipple.
Sponge rubber valve
A sponge-rubber-lined valve plate attached to a bimetallic strip, which controls the air intake temperature to the carburetor in some BL cars. The bimetallic strip moves the plate up or down according to temperature, in its extreme positions, the sponge rubber seals either the cold air intake or the hot air intake
Spongy brake pedal
Air in hydraulic lines, distortion or stretching of connecting parts, or swelling of hydraulic hose may allow pedal to be spongy or springy instead of solid.

Spongy lead
Pure lead which serves as the active material in the charged negative plates of a battery.

Spongy pedal
When there is air in the Brake lines, or shoes that are not properly centered in the Brake drums, the brake pedal will have a springy or spongy feeling when the brakes are applied. The pedal should normally feel hard when applied.

Spool balance valve
A hydraulic valve in automatic transmissions that balances incoming oil pressure against spring control pressure to produce a steady pressure to some control unit.
Spool valve
A hydraulic control value shaped somewhat like a spool upon which thread is wound.
  1. A tire-iron tool used to remove a tire (especially a bicycle or motorcycle tire) from its rim. Usually two or three spoons are necessary to do the job. Using a flat blade screwdriver instead of a spoon may puncture the tube.
  2. A tool used to turn star wheel adjusters and thus to adjust the brake lining-to-drum clearance.
Originally meant something that was different from the normal. Thus a sports car was a vehicle that was different from a general transportation car. Sports as a game (i.e., hockey, baseball, etc.) is an activity that is different from the normal routine of work.

A special carburetor port for ported vacuum
Sport and Imperial phaeton
Similar to the phaeton, but with extra equipment or refinements, such as wire wheels, trunk rack, and ultra-modish paint treatments and Finish. The Imperial type indicates a Tonneau or second windshield in front of the rear seat passengers.
  1. A motorcycle type which originally began as a Cafe racer. The rider is bent forward for better flow of the air (as opposed to the upright position of a touring bike). Also called a crotch rocket because of the strain it places on the rider’s crotch and because of its very fast speed.
  2. A motorcycle designed for optimal speed and handling characteristics, often with extensive bodywork.
Sport coupe
In other respects similar to the Coupe, it has a rumble seat in the rear deck and a small compartment for storage of golf clubs.
Sport roadster
In addition to being a roadster, it has provision for a rumble seat in the rear deck, along with a golf locker for storage.
Sports car
Term commonly used to describe a relative small, low slung car with a high performance engine and excellent handling. Originally, sports cars were faster than sedans; today, many sedans can easily outperform sports cars in terms of top speed as well as acceleration
Sports racer
A two-seat race car with enclosed wheels.
Dodge’s term for a stepside truck
Sports tourer
A bicycle whose structure, geometry, and components are designed to make it a compromise between one suitable for racing and one suitable for loaded touring — good for general pleasure riding.
Sport tourer
A motorcycle that combines the comfort and carrying capacity of a touring bike with the handling and power of a sportbike with larger fairings and hard, lockable luggage.
Sport utility vehicle
A vehicle built on a truck chassis but is configured much like a station wagon. Some examples are Blazer, Jimmy, Bronco, Explorer, Ram, and Cherokee
Sporty driving style
A manner of handling a vehicle in which the driver turns corners fast, brakes and accelerates hard, uses high revs in every gear, and shifts down before corners.
A small disc attached to a brake actuating lever.

Spot efficiency
To finish a round spot on a rough surface, usually around a drilled hole, to give a good seat to a screw or bolthead; cut usually 1.5mm deep.
Spot faced
On a connecting rod, a bolt head seating surface that is machined so it describes a radius on the inboard-side of the bolt head as viewed from the top of the bolt head
Spot glazing
Filling minor imperfections (sand scratches).
Spot lamp
An auxiliary light used to shine a narrow beam of light.
Spot magnetic electric brake
An electric brake design in which the electromagnet is a small disc (spot) attached to an actuating lever.
Spot Paving
A paving treatment that provides large asphalt patches for bad areas. It is a maintenance tactic used for aging pavement to hold it over until a major improvement can be undertaken. When the treatment is complete, there will be scattered spots along the roadway where new asphalt has been applied. The work is sometimes followed with a surface treatment.
Spotting in
The paint respraying of very small areas
Spot weld
Fastening parts together by fusing, at various spots. Heavy surge of electricity is passed through the parts held in firm contact by electrodes.
Spot welding
A type of resistance welding in which two pieces of metal are joined at a series of points (spots) by means of heat (usually electrically generated) and pressure; the most important welding method in auto body construction
Spot-weld drill
Spot-welded flange
A sheet metal strip forming a flange at the edge of panels joined by Spot welding
Spot-weld remover
  1. A special drill bit used to drill out weld spots on sheet metal material without damaging the panels.
  2. A tool for use with a hand drill; features reversible cutting blade to cut out weld spots without damaging the sheet metal material; the cut depth can be varied, e.g., to release the upper panel only
Abbreviation for Spark Output Signal
Sprag brake
A sprag is a stick (of wood or metal) which is inserted into gears or even into the dirt to stop the motion of something.
Sprag clutch
A clutch that will allow rotation in one direction but that will lock up and prevent any movement in the other direction.
Spray arc
Gas metal arc process which has an arc voltage high enough to continuously transfer the electrode metal across the arc in small globules.
Spray bell
A dome-shaped, rotating paint spray element
Spray booth
A closed section in a painting line in which paint is sprayed on workpieces or body shells
Spray chamber
Spray coating
An application method for chemical conversion coatings
Spray cooling
Method of refrigerating by spraying expendable refrigerant or by spraying refrigerated water.
Spray flap
Spray gun
An apparatus shaped like a pistol which delivers an atomized mist of liquid.

Spray gun nozzle cleaning unit
A special cleaning unit for paint shops which holds several spray guns in such a position that the nozzle is soaked in thinners
Spraying booth
A closed section in a painting line in which paint is sprayed on workpieces or body shells
Spraying viscosity
The viscosity required to make paint suitable for spraying, i.e., neither too thick nor too thin
Spray mist
A fogging caused in the course of spray painting; part of this settles as overspray on adjacent panels and nearby objects.

Spray pattern
The shape of the jet of spray leaving a spray gun
Spray process
Spray testing
Spread axle
  1. A trailer axle, usually 6 to 9 feet ahead of another axle and located near the center of the trailer.
  2. A tandem axle assembly spaced farther apart than the standard spacing of 54 inches. The U.S. federal bridge formula favors trailer axles with an eight or nine foot spread by allowing higher weight than on tandems with standard spacing. Also called spread tandem
  1. A hand-held tool used to apply body filler to a damaged area prepared for filling.
  2. A hydraulic jack with ends designed to reach behind dented double panels and to press them back into shape by the hydraulic action of the wedge-shaped ends.
  3. A device attached to the back of a dump truck to evenly distribute sand or sand/salt mixture on icy roads.
Spreader spring
A cross-shaped part made of spring steel sheet which applies radial pressure to the brake pads to prevent rattling.

Spread Tandem
A two-axle assembly with the axles spaced to allow maximum axle loads permitted by existing regulations. Distance between centers of axles of a spread tandem has generally been over 50 inches.


Three types of springs are used on vehicles for various purposes: Compression spring, Leaf spring, and Extension spring

Spring and damper settings
Suspension settings for springs and or struts. Stiffer settings provide better handling with a bumpier ride. Softer settings give a smoother ride but compromise performance.
Spring And Retainer
Spring balance
An instrument for measuring weight or force which does so by the elasticity of a spiral spring.
Spring bar
In a 5-bar convertible roof mechanism, it is an additional bar between the main bar and the rear window; spring loaded, it assists the main bar in shaping the roof; a similar effect can be achieved by spring-steel leaves embedded in the canvas
Spring beating
A metalworking process for removing pressure ridges in body panels in which a Spring beating spoon is laid on the ridge area and is gradually moved across the ridge while the spoon surface is hammered with a body hammer
Spring beating spoon
A light pressed-steel blade designed specially for beating on ridges; the spoon is placed directly on the ridge and sharp blows with a hammer are delivered to the back of the spoon, spreading the force over a large area
Spring booster
A device used to beef up sagging springs or to increase the Load capacity of standard springs.
Spring bow
In a 5-bar convertible roof mechanism, it is an additional bar between the main bar and the rear window; spring loaded, it assists the main bar in shaping the roof; a similar effect can be achieved by spring-steel leaves embedded in the canvas
Spring bracket
Spring brake
Emergency or auxiliary brake system using a spring load as a force for braking. May be automatically actuated by low air pressure or mechanically controlled for use as a parking brake.
Spring caliper
Spring cap
Spring choke
Spring clip
  1. A fastening device made of an incomplete circle of spring steel, e.g., for covers.
  2. A rebound clip which holds the spring leaves of a leaf spring together and to keep them in alignment.
  3. A fastener used to provide a screw hole for a sheet metal screw; certain variants of this fastener may be moved slightly at their mounting to provide a certain degree of adjustment.
Spring clutch
Spring collar
Spring compressor
A tool used to restrain coil springs for safe removal and installation. They are available in a variety of shapes, as manual or hydraulic designs; the most common type consists of two steel jaws running on a threaded screw which securely hook into the coil spring; turning a nut reduces the distance between the jaws and compresses the spring. This type of spring compressor is always used in pairs, e.g., to remove MacPherson strut springs.

Spring depressor
Spring divider
A divider with a spring for accurate setting
Springer fork
A motorcycle suspension system that uses large, exposed springs to dampen the impact of road irregularities.
Spring eye
Spring eyeSpring eye

A cylindrical hole formed by bending the end of a leaf spring around, for attachment to the vehicle

Spring hanger
A rubber-bushing bracket on a vehicle chassis on which a leaf Spring eye is mounted.


A term for suspension.

Spring lifter
Spring loaded
A device held in place, or under pressure from a spring or springs. Also called Spring biased
Spring lock
Spring lock washer
  1. A toothed, spring steel washer used as a locking device.
  2. A hardened coil wire having a slightly trapezoidal section after forming which functions as a spring take-up device to compensate for developed looseness and the loss of tension between the parts of an assembly and to prevent the nut from turning.
Spring mounting
Spring rate
Rate of deflection versus amount of load applied. In other words, how much force is needed to bend a spring a given distance.
Spring seat
Support on which the spring is anchored.

Spring shackle

Spring steel
A heat treated steel having the ability to stand a great amount of deflection and yet return to its original shape or position.
Spring tool
Spring type brake actuator
A unit that uss the stored energy in a spring to actuate the brake.
Spring washer
A warped-looking washer, typically used to prevent rattling by spring-loading certain movable threaded connections
Spring windup
The curved shape assumed by the rear Leaf springs during hard acceleration or braking.
  1. AlfaClick logo for books on

    A model of car (the Giuletta/Giulia Sprint Speciale) produced by Alfa-Romeo from 1959-61

  2. SprintClick image for books on

    A model of car produced by the Chevrolet division of General Motors from 1987 to 1988

A disc with teeth on its circumference for driving a chain, a general term that applies both to chainrings and to freewheel Cogs.

Sprocket wheel
Sprung mass
Sprung weight
This refers to the weight of all the parts of the vehicle that are supported by the Suspension system. Unsprung weight includes wheels and tires, brake assemblies, the rear axle assembly and other structural members not supported by the springs. Unsprung weight can be reduced with Independent rear suspension because the differential, and in some cases the brakes, can be attached to the body. Also called sprung mass.

Abbreviation for Service Programming System
Spur differential
A differential in front-wheel drive vehicle which uses spur gears rather than bevel gears, since input and output shafts are not at right angles.

Spur gear
Spur gearSpur gear

A gear on which the teeth are cut parallel to the shaft. They are used only for reverse gear in modern transmissions because they are noisier than Helical gears. However, they are cheaper to machine and require less power to turn than helical gears do. Also called straight-cut gear.

Spurt hole
A small hole in the Connecting rod big end that indexes (aligns) with the oil hole in the crank Journal. When the holes index, oil spurts out to lubricate the cylinder walls. Also called squirt hole
In the early 1900s, a light two-seater car. In the 1950s the word was revived by some Italian manufacturers for an open two seater sports car. Also spelled Spider.
Abbreviation for Sound Quality.
Sq. ft.
Abbreviation for square foot
Sq. in.
Abbreviation for square inch
A seat’s backrest (i.e., the part you rest your upper back against)
Squab panel
A panel supporting the rear seat squabs, separating the passenger compartment from the luggage space
Squab shelf
The rear parcel shelf
Square engine
An engine in which the Bore diameter and the length of the stroke are the same.

Square-four engine
A four cylinder engine in which each cylinder axis forms one corner of a square. This represents a way of doubling parallel twin cylinders to make a four cylinder unit, with two separate parallel crankshafts connected by gears or chain. This arrangement allows the engine width to be kept to that of a twin cylinder unit with only a small increase in length, thus providing the advantages of an in-line four without the problem of width. Applied in four-stroke and two-stroke motorcycles; in two-strokes mainly to permit rotary valve induction
Square jetting
  • Same size jetting in all four holes
  • Same size jets in the primary barrels and the same size jets in the secondaries (but different from those in the primary)
Square key
A small bar of any length but its height and width are the same.
Square Neck Carriage Bolt
A plain, truss or oval head bolt with a square neck to prevent rotation.
Square Nuts
Nuts that are square (i.e., four-sided) rather than hexagonal.
Square tapered bottom bracket
The industry standard bottom bracket shape until Shimano developed the Splined bottom bracket. Square tapered refers to the shape of the ends of the bottom bracket spindle.
The action of the rear end of the vehicle to point downward during hard acceleration. Squat is caused by a load transfer from the front to the Rear suspension.

An expression used particularly with two-stroke engines where the pistons have run without sufficient lubrication. It is caused by a poor Injection system or a pre-mix that is too lean (not enough oil in the gasoline).
Squeal shim
A device for detonating the airbag
Someone who rides a sportbike on the street as if he were on a racetrack.
A vehicle brand of which the 1925-1948 models are classic cars.
Squirrel cage
Fan which has blades parallel to the axis and moves air at right angles or perpendicular to fan axis. Which is much different from indoor ceiling fans or box fans.
Squirt box
A colloquial term for carburetor
Squirt hole
An area in the combustion chamber of some engines where the piston squishes or squeezes part of the fuel-air mixture at the end of the compression stroke. As the piston approaches Top dead center, the mixture is pushed out of the squish area and this promotes turbulence, further mixing of the fuel-air mixture and more efficient combustion.
Squish band
A narrow section of a combustion chamber in which the fuel charge is more compressed by the piston than in the rest of the chamber; designed to help direct the flow of the fresh charge and to improve scavenging
Squish combustion chamber
Squish combustion chamberClick image to supersize
Squish combustion chamber

The volume in the cylinder above the piston that can be a variation on almost any of the standard forms of combustion chambers. The squish area that gives it its name is the flat surface of the cylinder head that almost contacts the piston crown. When the piston rises on the compression stroke, it squishes, or squirts, the gas from this area into the combustion chamber with a swirling motion. This mixes the air-fuel mixture thoroughly for more complete vaporization and combustion. At the same time, the mixture is cooled as it swirls past the chamber walls, which are kept relatively cool by the water passages.

Squish zone
A narrow section of a combustion chamber in which the fuel charge is more compressed by the piston than in the rest of the chamber; designed to help direct the flow of the fresh charge and to improve scavenging
Abbreviation for Selective Ride Control
Abbreviation for Spark Retard Delay Valve
Abbreviation for ScientificResearch and Experimental Development Program.
Abbreviation for Service Reminder Indicator
  1. Abbreviation for Supplemental Restraint System, or Supplemental Restraint inflatable air-bag System. The letters appear on the steering wheel and/or Instrument panel. In fact, dual Airbags are standard in all of the 1998 cars, except for some sub-compacts and very small models.
  2. Abbreviation for Spark Retard Solenoid
SR sheathed glow plug
A Self-regulating sheathed-type glow plug
SRS warning light
An air bag warning light
Abbreviation for System Readiness Test
Cadillac SRX BooksClick image for books on
Cadillac SRX

A model of automobile manufactured by the Cadillac division of General Motors from 2004-current

  1. A vehicle brand of which the SS and SS Jaguar models for 1932-1940 except the 4-cyl. are classic cars.
  2. Abbreviation for Stainless steel.
  3. Abbreviation for Steamship
  4. Abbreviation for Speed Sensor (Honda)
Shift Solenoid #1 to provide pressure to force gear shifts
Shift Solenoid #2 to provide pressure to force gear shifts
Shift Solenoid #3 to provide pressure to force gear shifts
Shift Solenoid #4 to provide pressure to force gear shifts
Shift Solenoid #1 to provide pressure to force gear shifts
Abbreviation for Stamped, self-addressed envelope.
Shift Solenoid #2 to provide pressure to force gear shifts
Shift Solenoid #3 to provide pressure to force gear shifts
Abbreviation for Stress corrosion cracking
Shift Solenoid #4 to provide pressure to force gear shifts
Abbreviation for Seconds Saybolt Furol
Abbreviation for Solid state ignition system
SSR Pickup
SSRClick image for books on

A model of small pickup truck produced by the Chevrolet division of General Motors from 2003 to 2006

Abbreviation for Seconds Saybolt Universal
  1. Abbreviation for Short ton which is 2,000 lbs.
  2. Abbreviation for Scan Tool
Stab braking
  1. The quality or state of a vehicle to remain controllable.
  2. The ability of a ship to return to her normal upright position when listed by the action of waves, wind, etc.
  3. Property which allows an adhesive, coating, or sealer compound to be stored under specific conditions without loss of its original properties.
  4. The property of a system or element by virtue of which its output will ultimately attain a steady state. The amount of power that can be transferred from one machine to another following a disturbance. The stability of a power system is its ability to develop restoring forces equal to or greater than the disturbing forces so as to maintain a state of equilibrium.
  5. The ability of a governor to maintain its speed with either constant or varying loads without hunting.
  1. To make or keep stable
  2. To convert to a form that resists change. Organic material is stabilized by bacteria which convert the material to gases and other relatively inert substances. Stabilized organic material generally will not give off obnoxious odors.
A variety of devices used to keep the passenger compartment of a vehicle from swaying and lurching on sharp curves and turns.

Stabilizer bar
A transverse mounted Spring steel bar that controls and minimizes body lean or tipping on corners.

Stabilizer belt
A radial tire belt consisting of cords (usually fine steel wire) embedded in rubber directly beneath the tread and above the radial cord body plies
Stabilizer link
A suspension link which connects the anti-roll bar to the lower wishbone
Stabilizing plies
Two or more plies, of steel, fiberglass, etc., forming a belt around the circumference of a tire, between carcass and tread rubber. It reduces tread distortion of radial and bias belted tires.
Stable Signal
A traffic situation which is illegal in most places. Suppose the car in front of you is waiting to turn left at an intersection controlled by a traffic light. It is in the middle of the intersection with a green light, but the oncoming traffic is steady. Now the light turns amber (or even red) and the car completes its left turn. However, you are right on his bumper and you turn with him. And perhaps the car (or cars) behind you also turn at the same time. You and the other cars are stacking.

Stack end frame
A frame used to compress the individual cells together to maintain electrical conductivity. Also may be known as an end plate or compression end plate.
  1. A traffic procedure which is illegal in most places. Suppose the car in front of you is waiting to turn left at an intersection controlled by a traffic light. It is in the middle of the intersection with a green light, but the oncoming traffic is steady. Now the light turns amber (or even red) and the car completes its left turn. However, you are right on his bumper and you turn with him. And perhaps the car (or cars) behind you also turn at the same time. You and the other cars are stacking.
  2. The process of placing individual fuel cells adjacent to one another to form a fuel cell stack. Normally, the stack is connected in a series.
Stack life
The cumulative period of time that a fuel cell stack may operate before its output deteriorates below a useful minimum value
Stack test
Experiment where an electrical load is applied to a stack of fuel cells to determine its ability to perform. Normally, the output seeks two pieces of information. First is a current output at a specific cell voltage point. Second is a continuous voltage vs. current curve (polarization curve.)
Staged carburetors
Carburetors equipped with a secondary system. Staged carburetors are activated either mechanically or by a vacuum diaphragm. Think of staged four-barrels as a pair of two-barrels in parallel
Trucker slang for a customized bus used to carry entertainers from venue to venue as in ‘Wonder if Faith Hill is in that stagecoach?’
Stage Compressor
  1. To place items (like carburetors, pistons) so that every second item is offset from the previous one.
  2. The difference in the circumference of the tires on the right and left sides of the car. Since oval track racing is always done turning left, teams put larger tires on the right to help the car naturally turn left.
  1. A trade name given to alloy steel that is corrosion and heat resistant. The chief alloying elements are chromium, nickel, and silicon in various combinations with a possible small percentage of titanium, vanadium, etc.
  2. By AISI definition, a steel is called ‘Stainless’ when it contains 4 per cent or more chromium.
Stainless steel

  1. A type of steel containing nickel and chromium, which is resistant to corrosion
  2. Any steel containing four or more per cent chromium is classified as stainless.
  3. With the addition of 12% chromium to iron, stainless steel is formed. The chromium protects the iron against most corrosion or red-colored rust; thus the term ‘stainless’ steel. The ability of stainless to form a thin layer of protection on its outside surface, called a passive film, is its most important characteristic in preventing corrosion. The overriding purpose of stainless steel is to provide corrosion resistance against:
    • atmospheric conditions such as carbon dioxide, moisture, electrical fields, sulfur, salt, and chloride compounds
    • natural and artificially produced chemical
    • extremes of weather where cold temperatures cause brittleness and hot temperatures reduce strength and increase corrosion.
Stainless-steel exhaust system
A more hard-wearing and therefore more expensive system than one made of mild steel
Stainless-steel mesh
  1. A panel-beating tool formed like a dolly, but with a shaft attached allowing it to be clamped in a vice.
  2. The wooden bars which fit into the sides of the bed of a truck.
Stake Body
A flatbed with sides or stakes to retain the load.
Staked nut
A nut secured to a bolt with a metal tab (e.g., a wheel bearing adjusting nut)
An engine which stops unintentionally. The usual causes of stalling are sudden increase in load without an accompanying increase in fuel flow (often occurring when a driver engages the clutch to drive away without increasing the engine speed) and braking to a very low speed without disengaging the clutch

Stall speed
The test characteristic of a fluid converter; result of the stall test
Stall test
A short-time (5 seconds) full throttle operation with the vehicle brakes fully applied and the selector lever of an automatic transmission in D position; the test results in an engine speed (stall speed) that indicates the performance of the fluid converter
Stall torque
Torque developed when starting.
Stall torque ratio
The torque conversion in fluid converters on taking up drive, i.e., when the turbine is still stationary; stage of maximum torque multiplication
Stamped-steel wheel
Stamped-steel wheelStamped-steel wheel

A wheel for mass-produced automobiles that has a rolled-steel rim around a stamped center. The center hole fits over the front or rear hub, but the wheel is positioned by the mounting bolts or by lug nuts. Bolts and lug nuts fit into conical holes precisely located to make the wheel run true.

  1. A sheet metal part formed or shaped by pressing rolled sheet metal between metal dies (hardened metal blocks).
  2. Punching out parts with dies such as flat washers.
Stamp Road
Stanchion tube
The upper (non moving) tube on a bicycle suspension fork which is attached to the fork crown.
Standard air
Air having a temperature of 20°, a relative humidity of 36%, and pressure of 14.7 psia (101.3 kea). The gas industry usually considers 16°C as the temperature of standard air.
Standard atmosphere
Condition when air is at 14.7 psia pressure at 20°C temperature and a relative humidity of 36 percent.
Standard Brass Thread
Standard conditions
  1. Used as a basis for air conditioning calculations temperature of 20°C, pressure of 29.82 inches of mercury (Hg.), and relative humidity of 30 percent.
  2. The test or operating conditions that have been predetermined to be the basis of the test in order to have reproducible, comparable sets of test data. Typical conditions that are standardized are fuel and oxidant flow rates and ratios, temperature, pressure, electrode area, catalyst loading, etc.
Standard Cycle
Standard Efficiency
Standard equipment
Those parts and systems of a vehicle supplied by the manufacturer at no extra cost, i.e., they are included in the basic price for a given model
Standard Fine
Standard fluorescent
A light bulb made of a glass tube coated on the inside with fluorescent material, which produces light by passing electricity through mercury vapor causing the fluorescent coating to glow or fluoresce.
Standard Industrial Classification
(SIC) industry class that represents a level of organization of production by type of specialization. Currently the 1980 Standard Industrial Classification is in effect identifying each industry at the 4 digit level. Replaced by NAICS
Standard Pipe Thread
Standard rim
A rim that has been calibrated and found to meet the precise measurements specified by Tire and Rim Association, Inc. or, where applicable, by European Tire & Rim Association.
Standards Association
Standards Institution
Standards Organization
Standard Specification
Standard transmission
A transmission that must be shifted manually to effect a change in Gearing. Also called conventional transmission or manual transmission.
Standard U.S. Gallon
A unit of volume in the U.S. Customary System, used in liquid measure, equal to 231 cubic inches (3.7854 litres), and used to distribute fuel.
Standard wheel
The original wheel on a vehicle supplied by the car manufacturer
Standard Whitworth
Standard width chain
Standard Wire Gauge
(SWG) A series of sizes of the diameter of wire.
Standard work week
Average number of hours worked normally scheduled in a work week.
A power circuit equipment, device, or component available to be connected into the circuit to perform a function when the preferred component has failed or is inoperative.
Standing proud
A situation where an object (e.g., rivet or bolt) does not sit flush with the surrounding material
Standing start
A race which begins with none of the vehicles in motion.
Stand proud
A proprietary polyamide with unusual temperature stability, mechanical strength, and resistance to oil and grease
StanzaClick image for books on

A model of automobile manufactured by Nissan in Japan

Abbreviation for Self Test Automatic Readout

The right-hand side of a ship when facing forward
Star Fangled Nut
StarletClick image for books on

A model of automobile manufactured by Toyota

To use the starter motor to crank the engine until it fires and runs on its own.

Start boosting
Bypassing the ballast resistor of an ignition system when starting the engine
Start bypass
Bypass of the ballast resistor
Start enrichment
  1. A small electrical motor that causes the engine crankshaft to begin to turn, which starts the engine running and so starts the vehicle. Invented in 1911 by Cadillac engineers, the manual crank-starter was replaced by an electric motor and thus made it easier and safer for people to start and drive cars. Also called the Cranking motor.
  2. A person who indicates that a race is to begin.
Starter drive
Starter inhibitor switch
A switch which prevents starting of the engine unless certain system conditions are fulfilled; e.g., on cars with automatic transmission, the selector lever must be in Neutral or Park
Starter interlock
A switch which prevents starting of the engine unless certain system conditions are fulfilled; e.g., on cars with automatic transmission, the selector lever must be in Neutral or Park.

Starter lockout
A switch which prevents starting of the engine unless certain system conditions are fulfilled; e.g., on cars with automatic transmission, the selector lever must be in Neutral or Park
Starter motor

Starter punch
A tool used to start the removal of pins, shafts, or rivets by breaking them loose; longer and thinner than a Drift punch
Starter ring gear
A gear fitted around the flywheel that is engaged by teeth on the starter drive to crank the engine
Starter solenoid
A device that uses electrical current to start and engage the starter. Also called a starter relay


Starter switch
Starter switch control cable
A mechanical cable to the starter switch on vehicles without a starter solenoid (e.g., Fiat 500)
Start from rest
To drive off from a standing start
Starting carburetor
A simple slide carburetor which works in parallel with the main carburetor and acts as a starting aid
Starting handle
A cranked handle for turning an engine over manually
Starting interlock
Starting relay
Electrical device which connects and/or disconnects starting winding of electric motor.
Starting switch
On certain classic cars, separate switches are used to turn the ignition on and to operate the starter; on such cars, the starting switch was a push button, often located in the center of the instrument panel; on modern cars, the starting switch is integrated in the ignition and starter switch
Starting system
The portion of the Electrical system that starts the vehicle. Consists of the Ignition switch which closes the circuit and allows current to flow from the battery to the starter by way of the Starter solenoid. Also called the Cranking circuit.
Starting torque
  1. The amount of torque available, when stationary, to move and accelerate the load.
  2. The torque or twisting force delivered by an electric motor when energized
Starting winding
Winding in electric motor used only briefly while motor is starting.
Start injector
Start of brake application
The instant at which the brake control system is actuated as determined by initial brake control movement.
Star wheel
An adjusting nut on a drum brake or clutch. The portion of a brake action that turns the adjustment screw
Star-wheel adjuster
A drum-brake mechanism that separates the brake shoes at the bottom; it rotates a nut on a threaded link to adjust brake-lining clearance.
State car
State controller
State Current
State highway
A broad highway designed for high-speed traffic within a particular state of the U.S. When such a highway crosses over to another state, its highway number may change.

State Ignition System
State indicator
State of charge
Stated residual value
The stated residual value is usually the same as the end-of-lease purchase price. The higher the stated residual value of the car, the lower your monthly payments. Stated residual values are often higher or lower than the expected residual value for a car, the lessor can raise or lower the monthly payments and the net interest rate for the lease. Stated residual value also determines whether you should buy the vehicle at the end of the lease. If at the end of a lease, the vehicle’s market value is less than the stated residual value, the lessee would be prudent not to purchase the car. On the other hand, if the actual market value were greater than the predetermined residual, then the lessee could buy the car, sell it, and pocket the difference.
Static balance
When a tire, Flywheel, crankshaft, etc., has an absolutely even distribution of the weight mass around the axis of rotation, it will be in static balance. For example, if a front wheel is jacked up and the tire, regardless of where it is placed, always slowly turns and stops with the same spot down, it would not be in static balance. If, however, the wheel remains in any position in which it is placed, it would be in static balance, (bearings must be free, no brake drag, etc.). Also called kinetic balance.

Static belt
A seat belt with no automatic belt retractor and whose length is manually adjusted.

Static electricity
Electricity generated by friction between two objects. It will remain in one object until discharged.
Static friction
The friction existing between two surfaces at rest.

Static head
Pressure of fluid expressed in terms of height of column of the fluid, such as water or mercury.

Static high-voltage distribution
High-voltage distribution achieved without a rotary distributor, using multi-spark ignition coils or one coil per spark plug
Static ignition timing
An obsolete timing procedure carried out by rotating the engine until the timing marks are aligned and then connecting a test lamp or a voltmeter between the negative coil terminal and ground; when the points open, the test lamp lights up or the voltmeter registers battery voltage. The opposite is dynamic or stroboscopic ignition timing
Static loaded radius
Static mixer
A motionless mixer which has a series of fixed, geometric elements enclosed within a tubular housing. The internal elements impart flow division and radial mixing to the media flowing through the housing to produce a uniform dilution of the production.
Static pressure
A certain amount of pressure that always exists in the Brake lines even with the brake pedal released. Static pressure is maintained by a Check valve.

Static seal
An oil seal between two stationary parts. Opposite to Dynamic seal
Static shield
A device found on some distributors that reduces radio interference caused by the working of the vehicle’s ignition system.
Static timing
An obsolete timing procedure carried out by rotating the engine until the timing marks are aligned and then connecting a test lamp or a voltmeter between the negative coil terminal and ground; when the points open, the test lamp lights up or the voltmeter registers battery voltage. The opposite is dynamic or stroboscopic ignition timing
Static Voltage
The voltage created by the buildup of static charges on people or objects.
Stopped, for example in a line of traffic, at a stop light or in a parking space
Stationary blade compressor
Rotary pump which uses a non-rotating blade inside pump to separate intake chamber from exhaust chamber.
Stationary trainer
A device to which you attach your bicycle so you can ride in place as an exercise bike.
Station button
Station memory
Station wagon
(SW) Originally this was a car with an enclosed wooden body of paneled design with several rows of folding or removable seats behind the driver. It became a different and popular vehicle after 1945. There is usually A tailgate but no separate luggage compartment. Early station wagons and compact station wagons had only two doors while the larger ones had four doors. The British term is estate car.

  1. A small hub, upon which a series of Vanes are affixed in a radial position, that is so placed that oil leaving the Torque converter Turbine strikes the stator vanes and is redirected into the pump at an angle conducive to high efficiency. The stator makes Torque multiplication possible. Torque multiplication is highest at stall when the Engine speed is at its highest and the turbine is standing still.
  2. StatorStator

    The stationary windings in an alternator in which electric current is generated; located between drive end and slip-ring end fittings, consisting of a stator frame with windings in three circuits to generate three-phase current which is then rectified by diodes.


  3. A self-contained unit of the magnetic pick-up, consisting of a permanent magnet, an inductive winding, and the pick-up core; the stator can be a disc-shaped pole piece with stator tooth or a simple pole piece
  4. The wheel with curved blades (sometimes adjustable) mounted on a one-way clutch in a fluid converter or automatic transmission. It serves as a reaction member, i.e., it multiplies the torque output of the turbine by increasing the momentum of the fluid flow acting on the latter.
  5. The fixed electrical windings on a magneto, Alternator, or Generator. It turns within the rotor.
Stator, motor
Stationary part of electric motor.
Stator roller clutch
A device which holds the stator stationary in a fluid converter as long as its blades are struck by the fluid flow against the rotational direction of pump and turbine; if the fluid flows in the direction of rotation, the stator starts running
An arm or brace use to support another component.

Abbreviation for standard, as in std. transmission.

Steady state current
Current does not vary in intensity, but remains constant
A single wide plate that is butt-connected to two narrow plates, usually near the ends of a ship.
Stealth bra
A nose covering composed of composite materials that absorb microwaves emitted by radar devices and significantly diminish the return signal, making a car less detectable to police radar; ineffective against speed cameras or light-operated speed guns.

Water in vapor state used as the working fluid in steam turbines and heating systems.

Steam Boiler
Steam clean
To clean the engine with a high-pressure jet of steam
Steam engine
An External combustion engine where water is converted to steam in a boiler outside the cylinder. The steam is then admitted to the cylinder where it expands against a piston. As the steam expands it cools and begins to Condense. This mixture of water droplets and steam is forced out of the cylinder on the return stroke and into the condenser where the remaining steam is Condensed into water. This water is forced into the boiler by a pump and the cycle is repeated. Steam engines have some notable drawbacks slow warm up, freezing of the water system in cold weather, and contamination of the water by Scale, oil, and Sludge which can wreak havoc with the boiler, pumps, and condenser. But they also offer certain advantages the potential for high fuel economy with low emissions, the ability to start from rest against a load so a clutch is not needed, and the torque developed is greatest at low rpm so in some applications a multiple-ratio Gearbox is not necessary.
Steam heating
Heating system in which steam from a boiler is piped to radiators in space to be heated.
Steam injection system
Based on the same principle as water injection systems, the steam injection system uses engine exhaust heat and a boiler to pre-heat and boil the water before it is injected into the inlet manifold as steam
Steam jet refrigeration
Refrigerating system which uses a Steam venturi to create high vacuum (low pressure) on a water container causing water to evaporate at low temperature.
Steam reforming
The process for reacting a hydrocarbon fuel, such as natural gas, in the presence of steam to form hydrogen as a product. This is the commonly preferred method of bulk hydrogen generation.
Steam-to-carbon ratio
The number of moles of water per mole of carbon in either the Reformate or the fuel streams. This term is used when steam is injected into the Reformate stream for the water-gas shift reaction or into the fuel for steam reforming.
Steam trap
Automatic valve which traps air but allows condensate to pass while preventing passage of steam.
A vehicle brand of which the 1925-1948 models are classic cars.
An alloy of iron containing a small (up to 2%) percentage of carbon.

Steel backing
The supporting part of a plain bearing insert
Steel belted radial (SBR)
A Radial tire with belts of steel to provide both protection and longevity.
Steel belted radial tire
A Radial tire with belts of steel to provide both protection and longevity.
Steel body
Steel casting
Cast iron to which varying amounts of scrap steel have been added
Steel pack muffler
A straight through (no Baffles) muffler using metal shavings surrounding a perforated pipe. Quiets exhaust sound.
Steel strip
A sheet of steel less than 600 mm wide
Steel strut
Steel strutSteel strut

Steel braces or rings which are cast into aluminum pistons. Because steel expands slower than aluminum, the steel struts tend to control or minimize the expansion of the piston.

Steel thrust belt
A large number of steel plates with slots in each side to receive the two composite steel bands which hold them together; transmits torque between two pulleys
Steel wheel
Steel wheelSteel wheel

A wheel consists of a steel disc and steel rim which are welded together to provide better impact-resistance, lower price, and higher weight than alloy wheels.

Steep angle
Steep angles
Angles that position frame tubes relatively closer to vertical than do Shallow angles.
Steerable Dolly
Used in transporting extremely long objects, some can be steered remotely from the cab.
Steer axle
In trucks, this is the most forward axle used for steering. Also called front axle
Steer effect
Steerer tube
The tube that forms the top of the fork and rotates inside the Head tube of a bicycle.
A mechanism for controlling the direction of a vehicle.

Steering, Ackermann
Steering angle
A horizontal angle between the plane of a steered wheel when cornering, and the plane when adjusted straight ahead steering angle sensor. Also called lock angle
Steering arm
Arms, either bolted to, or Forged as an integral part of the steering knuckles. They transmit the steering force from Tie rod to the knuckles, thus causing the wheels to pivot. Also called Tie rod arm.
Steering axis
The line through the center of the Ball joints in a Front suspension system. The line that intersects the upper and lower steering pivots on a steered wheel.

Steering axis inclination
(SAI) An alignment adjustment that allows the steering wheel to return to the straight-ahead position when the car comes out of a turn.

Steering axle
An axle that directs control of the vehicle. It can be powered or non-powered and more than one steering axle can be present.
Steering box
The part of the steering system that is located at the lower end of the steering shaft; changes the rotary movement of the steering wheel into the linear motion of the front wheels for steering
Steering column
A shaft connecting the steering wheel to the Steering gear assembly. Also called the steering shaft.

Steering column controls
Consist mainly of control stalks for some or all of the following lights, windshield wipers and washers, direction indicators, and horn
Steering column gearchange
Steering damper
A shock absorber-like bump stop which absorbs vibrations in the steering system
Steering Effect
Steering feel
Steering feel is the general relationship between forces at the steering wheel and handling. Ideally, the steering effort should increase smoothly as the wheel is rotated away from center. In addition, the steering effort should build as the cornering forces at the steered wheels increase. Finally, the friction built into the steering mechanism should be small in comparison with the handling-related steering forces.
Steering gain
The relationship between Yaw and the steering wheel‘s position and effort. All three should be proportional and should build up smoothly.
Steering gear
The gears, mounted on the lower end of the Steering column, that are used to multiply driver turning force. It converts the rotary motion of the steering wheel into straight-line motion. This straight-line motion then moves the linkage connected to the steering arms and attached to the steering knuckles and this causes the front wheels to move to the right or the left in response to the steering wheel direction.
Steering gear arm
Steering gearbox
Steering gear shaft
The rotating, torque-transmitting part of the steering column
Steering geometry
  1. A term sometimes used to describe the various angles assumed by the components making up the front wheel turning arrangement, Camber, Caster, toe-in, etc. Also used to describe the related angles assumed by the front wheels when the vehicle is negotiating a curve.
  2. The geometrical relationship between motorcycle frame, the angle of the fork, and the position of the front tire.
Steering head
That portion of a motorcycle frame where the front fork and wheel assembly attach to the frame.
Steering input
Steering kickback
The sharp and rapid movements of the steering wheel as the front wheels encounter obstruction in the road; the shocks of these encounters kick back to the steering wheel
Steering knuckle
Steering knuckleSteering knuckle

The inner portion of the spindle that is affixed to and pivots on either a kingpin or on upper and lower Ball joints.

Steering knuckle angle
The angle formed between the Steering axis and the center line of the spindle. This angle is sometimes referred to as the included angle.
Steering knuckle arm
Steering linkage
The system that connects the steering wheel to the front wheels and allows the wheels to change direction in response to commands from the driver. Contains Grease fitting to cushion against wear and friction.

Steering lock
  1. The number of degrees that the front wheels can be turned from straight ahead before they are physically restrained from turning any further. Generally, the more lock designed into the front geometry, the smaller the turning circle but the more the tires scrub as the wheels approach the extreme lock positions. Turns lock-to-lock refers to the number of rotations of the steering wheel required to go from one extreme lock position to the other.
  2. The locking mechanism usually contained in the Steering column that locks the steering wheel when the Ignition switch is turned off or the key is removed from the switch.
  3. A lock on a motorcycle which prevents the front wheel from being turned left or right.
Steering overall ratio
The ratio of the degrees you must turn the steering wheel to turn the road wheels one degree from their straight ahead position.
Steering pressure sensor
A detection device that provides information on the steering pump pressure for idle speed control.
Steering pump
Steering rack
The device by which the movement of the steering wheel is transferred to the front wheels of an automobile.
Steering ratio
The ratio of the Gearing within a Steering system such as the rack to the Pinion or the Worm gear to the recirculating nut.
Steering response
A subjective term that combines Steering feel and Steering gain.
Steering rod
One of two metal rods on each end of the Steering rack that connect it to the front wheels via Ball joints (Tie rod ends).
Steering shaft
Steering spindle
A shaft-like projection from the steering knuckle to which the wheel is mounted.


Steering support
The mounting locations and reinforcements for attaching the steering box to the bulkhead or side member
Steering support structure
The mounting locations and reinforcements for attaching the steering box to the bulkhead or side member
Steering swivel
Steering-swivel axis
Steering-swivel inclination
Steering system
The mechanism that allows the driver to guide the vehicle down the road and turn the wheels as he desires. The system includes the steering wheel, Steering column, Steering gear, linkages, and the front wheel supports.
Steering wheel
The device that the operator uses to control the direction of the front wheels. Most are circular with spokes that attach to the Steering column.

Steering wheel and brake lock
An anti-theft device in the form of an extendable steel rod that engages in a spoke of the steering wheel and the brake or clutch pedal; when locked, neither wheel nor pedal can be operated
Steering wheel balance
Measures the steering wheel angle in an automatic steering wheel centering system
Steering wheel centering
Adjusts the steering wheel and steering system so that the wheel is in its center position when the front wheels are pointing straight ahead
Steering wheel damper
Steering wheel puller
A special puller for removing steering wheels
A proprietary range of very hard, wear-resistant alloys containing cobalt, chromium, carbon, tungsten, and molybdenum. It has a high melting point, good corrosion resistance, and unusual hardness when hot. It is used for tools, castings, valve seat inserts, coating exhaust valves, etc.
  1. The upright bow frame forming the apex of the intersection of the forward sides of a ship.
  2. The component that holds the handlebars of a bicycle and mounts to the steerer tube.
Stem length
On a bicycle, the distance from the center of the stem bolt to the center of the handlebar clamp. Stem length is usually represented in metric measurement (centimetres or millimetres) rather than imperial (inches).
Stem rise
The angle of the stem measured in degrees. Most road bicycles have stem rises of either 17° (a more upright position), or 0° (putting the rider in a lower, more aerodynamic position).
Stem seal
A valve stem seal between the valve and cylinder head.

Stem seal installer
Stem seal pliers
Stem, threaded
Stem, threadless
A ledge formed by an edge setter in a sheet metal panel to provide a level mounting and welding surface with the adjacent panel.

Step bar
A centerstand tang located on a motorcycle centerstand
Step Bolt
A plain, circular, oval head bolt with a square neck to prevent rotation.
Step Bumper
A bumper that can also function as a stepping platform either into or out of a cargo body, usually these bumpers are mounted relatively close to the ground.
Step deck
Step feeler gauge
A feeler gauge with metal feeler blades; the thickness of the blade increases from one end of the blade to the other
Step gearing
Step joint
See Lap joint
Stepless transmission
A Continuously variable transmission
Step on it
To increase the speed of a vehicle.
Step on the accelerator
The action of pressing down on the gas pedal (accelerator) to cause more fuel to enter the engine thus making the vehicle go faster. Opposite to ease up on the accelerator.
Step on the gas pedal
The action of pressing down on the gas pedal (accelerator) to cause more fuel to enter the engine thus making the vehicle go faster. Opposite to ease up on the gas pedal.
Step on the throttle pedal
The action of pressing down on the throttle pedal (accelerator) to cause more fuel to enter the engine thus making the vehicle go faster. Opposite to ease up on the throttle pedal.
Stepped compression ring
Stepped piston
An obsolete design of two-stroke pistons; the diameter of the lower part of the piston was larger than the top diameter; it ran in a similarly stepped bore and was said to give better compression of the incoming mixture
Stepped planet gear
A planet gear with different diameters
Stepper motor
Stepper motorStepper motor

On some carburetor cars, stepper motors are used to adjust the air/fuel mixture; they are controlled by the ECM. Vacuum reduces flow of fuel into the carburetor’s metering circuits

Step plate
A small step for climbing into a vehicle (e.g., on an ATV or SUV)

Step Running Board
Stepside truck
A pickup truck style in which there is some kind of indentation just behind the cab to allow you to enter the bed. Also called (by Ford) Flareside, (by Dodge) Sportside
Step steering input
A rapid change in steering angle, for example when a steered wheel hits an obstacle
A motorcycle/scooter frame layout with a low structure between the seat and the steering head. On early machines it was commonly called an open frame
Step valve
A valve having a rotating plug with, generally, three positions and different rates of fuel flow for each, the plug being actuated by a solenoid or motor-driven rack and pinion and a cam arrangement which, together with a combination push-button switch, determines the position assumed by the plug.
Step Van
A lightweight delivery truck designed so the driver can step into and out of the cab as well as into the rear cargo area.
(sr) A unit of solid angular measure. It is defined as the solid angle subtended at the center of a sphere by an area on its surface numerically equal to the square of the radius.
An abbreviation for stereophonic. It indicates sounds which appear to have their source distributed in space even when they are emitted by the vehicle’s speakers.

Steri lamp
Lamp which has a high-intensity ultraviolet ray used to kill bacteria. Also used in food storage cabinets and in air ducts.
SterlingClick image for books on

A make of automobile manufactured by the Sterling Motor Cars, a division of the Rover car company of the UK. Includes 825 (1988) and 827 (1989-91)

Stern cruiser
Stern frame
A large casting attached to the after end of the keel, incorporating the rudder gudgeons and propeller post in single-screw ships
The vertical part of the stern frame to which the rudder is attached
Stern transom
Stern tube
The watertight tube enclosing and supporting the propeller shaft on bearings
The reverse movement of a vessel.


A device (such as used by doctors) to detect and locate abnormal engine noises. A very handy tool for the trouble-shooter.

Stevens Duryea
A vehicle brand of which the 1925-1948 models are classic cars.
A vehicle brand of which the 1925-1948 models with required application are classic cars.
Short Term Fuel Trim Fuel adjustment based on HO2S sensor input
ST Fuel Trim
Abbreviation for Short Term Fuel Trim
  1. Abbreviation for Shimano Total Integration, Shimano’s name for it shifting brake levers
  2. Abbreviation for Self-Test Input (Ford)
Sticker price
A manufacturer’s suggested retail price (as displayed on an affixed sticker), usually subject to a negotiable discount
A fusing of the electrode to the surface of the piece being worked on, mainly at the beginning of the welding cycle
Stick shift
This refers to a Transmission that is shifted manually through the use of various forms of linkage. Often refers to the upright Gearshift stick that protrudes through the floor.

Sticky clutch
A shortened form of static friction; the frictional force which must be overcome to set one object in motion when it is in contact with another
  1. Not easily bent or turned. As opposed to a rigid object, a stiff object does not break when subjected to bending stress, and implies a certain degree of flexibility; a bridge, for example, is stiff, not rigid, and steel panels are inherently stiff; however, a particularly high degree of stiffness, e.g., when steel panels are shaped to a load-carrying structure, is sometimes referred to as rigid.
  2. A stiff ship is one which have a short period of roll and therefore will roll uncomfortably
  1. An angle, T-bar channel, built-up section etc, used to stiffen plating of a bulkhead, etc.
  2. Small metal strips placed crosswise to the roof at intervals along the inside surface to which the headlining and inside trim is secured.
A stiff ship is one which have a short period of roll and therefore will roll uncomfortably.

Stiffness under flexure
A measure of the resistance offered by a test specimen to its tendency to bend under the action of forces (own weight)
Stiff nut
Still-air pocket
An area of relatively turbulence-free air immediately behind the windshield of convertibles with the top down
Still gas
Any form or mixture of gases produced in refineries by distillation, cracking, reforming, and other processes. The principal constituents are Methane, ethane, Ethylene, normal Butane, Butylene, Propane, Propylene, etc. Still gas is used as a refinery fuel and a petrochemical feedstock. The conversion factor is 6 million BTU’s per fuel oil equivalent barrel.
Stillson wrench
A very large heavy-duty adjustable wrench
Stinger Fifth Wheel
Seen most commonly as the connection point for auto-carriers, but are also seen on some logging rigs. The inverted fifth wheel is mounted behind the rear axles, at the very end of the tractor, less than a foot off the ground.
Stink-bomb smell
Stirling engine
  1. An external combustion engine that uses air or an inert gas as the working fluid operating on a highly efficient thermodynamic cycle. The heat released from the burning fuel is transferred to the confined gas (such as hydrogen) which activates the pistons; named after the Scottish engineer, Robert Stirling (1790-1878)
  2. An External combustion engine in which heat is applied through the wall of a chamber within which a gas is successively heated and cooled, alternately expanding and contracting to power a piston inside the chamber. Its advantages include exceptional silence, lack of vibration, long life, high efficiency, extremely low emissions and adaptability to many different kinds of fuel. Its main drawbacks are the need for extremely effective seals, inflexible control systems, and cost.
Stirring paddle
A component of the agitator of a paint power mixer
Stirrup bolt
A U-bolt
Stirrup cable
On bicycle centerpull brakes, a short cable, each end of which attaches to a brake arm and which is pulled up at the center to activate the brakes.
STI shifters
Abbreviation for Shimano Total Integration Shifters. STI combination brake levers and shift levers found on a bicycle provide the ability to shift gears without taking your hands off of the handlebars.
A hard rolling method used to both remove trapped air and improve rubber contact for better adhesion, during repair, and retreading.
Abbreviation for Self-Test Output (Ford)
Stock car
A car as built by the factory (i.e., production car). Usually one that is raced without any modifications beyond factory installed equipment.

The stock, or original equipment.
Having the exact proportions for a particular chemical reaction
Stoichiometric ratio
In a spark-ignition engine, the ideal air/fuel mixture ratio of 14.71, which must be maintained on engines with dual-bed and three-way catalytic converters.

The unit of kinematic viscosity
On a tandem bicycle, the person on the front is the captain and the person behind is the stoker.
Stone Bond
Stone chip damage
A paintwork defect caused by gravel or stones
Stone deflector
A separate panel fitted below the front bumper or on the leading edge of the rear fender to provide protection from rocks, dirt, etc.
Stone guard
A separate panel fitted below the front bumper or on the leading edge of the rear fender to provide protection from rocks, dirt, etc.
Stone shield
A separate panel fitted below the front bumper or on the leading edge of the rear fender to provide protection from rocks, dirt, etc.
  1. A component which limits the motion, travel, or stroke of a moving part.
  2. A fixed point on a control, such as a temperature limit control, which prevents the adjustment of the control beyond the stop point.
  3. A colloquial term for an abutment.
Stop-and-go penalty
Punishment for a rule infraction during a race (usually speeding down pit road). The driver must come down pit road, stop in his pit stall, usually for 15 seconds, then proceeds back to the track.
Stop leak


Stop light
  1. A red light on a traffic signal indicating that vehicles should stop.
  2. A Brake light
Stoplight switch
A switch which completes the electrical circuit to the stop lamp(s) when the brake(s) is (are) applied.
A filler or putty used for filling holes, dents, etc.

Stopper plate
Stopping distance
The total amount of time (translated into distance) a vehicle and driver need in which to come to a halt; the shortest stopping distance is the reaction (or thinking) distance (of the driver) added to the braking distance (of the vehicle)

Stopping Speed
Stopping Time
Stop Screw
Stop sign
Stop signStop sign

In most countries, an eight sided red sign with the word ‘STOP’ or its language equivalent.

Stop solenoid
Stop valve
The primary steam valve attached to a boiler to control the steam supply and to isolate the boiler from the main steam pipe

Stop wheel
Storage battery
A rechargeable single cell or connected group of two or more storage cells such as the type used in vehicles. The opposite of primary battery.


Storage Capacity
Storage cell
An electrolytic cell for generating electric energy; rechargeable by sending a current through it in the opposite direction to the discharging current
Storage Field
A general term for provisions, materials and supplies used aboard ship.

A hot car that really moves out (i.e., accelerates rapidly).
To dry a coat of paint in heat.

Generally refers to Chevrolet (GMC) 6-cylinder, in-line, valve-in-head (Push rod operated) engine.
Stove head
Old term for truss head
A process of drying or curing a paint coating by the application of heat; immediately after stoving, the paint film is still soft, taking some time to harden
The placing of goods in a ship in such a way as to ensure the safety and stability of the ship
Abbreviation for standard temperature and pressure which is 25°C and 300 mm Mercury
Straddle cable
Straight cut gears
Straight-cut gear
Straight-cut gearStraight-cut gear

A gear that has teeth cut in the edge of the circumference of the gear. Unlike a Helical gear, the teeth are cut in line with the shaft on which it fits. It is used only for reverse gear in modern transmissions because it is noisier than a Helical gear. However, it is cheaper to machine and require less power to turn than a helical gear does. Also called Spur gear.

A rule-type tool without graduation for checking, e.g., warp of cylinder block and head
Straight eight
An eight-cylinder in-line engine
Straightened panel
A panel brought into its original shape with hammer and dolly or straightening equipment
Straight engine
Straightening bench
A workbench or fixture equipped to hold single panels such as doors or hoods for straightening and metalworking jobs
Straightening kit
Powerjacks used to straighten localized body damage, essentially comprising special ram cylinders, pumps, attachments, and extensions
Straightening set
Powerjacks used to straighten localized body damage, essentially comprising special ram cylinders, pumps, attachments, and extensions
Straight head chipping hammer
Straight-line speed
The highest speed obtainable by a vehicle driving in a straight line.
Straight-line stability
Straight-line tracking
The ability of a car to resist road irregularities and run in a straight line without steering corrections.
Straight pattern snips
Snips with cutting blades designed for straight cuts on sheet metal material
Straight polarity
(Electrode negative-cathode) connecting DC to cause electrons to flow from the electrode to the base metal.
Refers to a petroleum product produced by the primary distillation of crude oil, free of cracked components.
Straight six
A six-cylinder in-line engine
Straight-through side styling
An All-enveloping body
Straight-through silencer
A type of absorption silencer with a single perforated tube surrounded by sound-absorbing fiber which creates less back pressure and consequent loss of power than other types
Straight time
The actual time that a mechanic takes to complete a repair job. In contrast with Flat rate.
Straight Truck
straight truckStraight Truck

A vehicle which carries cargo in a body mounted to its chassis, rather than on a trailer towed by the vehicle. Examples include refuse, tank, and dump trucks. Straight trucks may or may not pull trailers.

Straight weight
Term designating motor oil as suitable for use within a narrow range of temperatures. Outside the narrow temperature range its flow characteristics will not adequately lubricate.
Straight weight engine oil
Straight-weight oil
Oil suitable for use within a narrow temperature range; outside this range, its flow characteristics will not allow adequate lubrication. Also called single-grade oil.

Reaction of an object to a stress.
  1. A wire mesh filter, as used in an oil pump strainer in the sump.
  2. Device such as a screen or filter used to retain solid particles while liquid passes through.
Strain hardened
To increase hardness and strength by (a) cold working of raw material by a steel mill or (b) cold forming by a fastener manufacturer can sharply increase tensile strength and hardness, so that ordinary material from a steel mill may often be used. However, fasteners that are milled from bar will decrease in strength and hardness, so that raw material would need to be strain hardened by a steel mill before milling fasteners.
Strain in the drive train
Strains resulting from the different track arcs traveled by the four wheels of a vehicle when cornering with center or axle differentials locked up
A fore and aft course, or row, of shell or other plating. Also see:

One of a number of wires twisted together to form an electrical conductor or cable
The running of a ship on shore on a beach.
An old colloquial term for Choke
  1. A long flexible strip (usually of leather or rubber) used to connect two items.
  2. A lead section to which battery plates of a group are joined.
Strap drive
A drive transmitted from the clutch cover to the clutch pressure plate in diaphragm spring and coil spring clutches, using flexible spring-steel straps attached to the clutch cover
Strap wrench
Filter wrenchStrap wrench

A tool for loosening and tightening round or irregularly shaped objects such as oil filters, featuring a strap which is wrapped around the object, and a lever or key by means of which the object is turned

A condition that occurs in blended fuels that have a compatibility problem. It is usually experienced when paraffinic based oils are mixed with asphaltic based oils, causing asphaltenes to precipitate and settle to the bottom of the tank.
Stratification of air
Condition in which there is little or no air movement in room; air lies in temperature layers.
Stratified charge
In a SI engine, an air/fuel charge which consists mainly of a lean mixture and a small layer or pocket of rich mixture; the rich mixture is ignited first, then ignition spreads to the leaner mixture filling the rest of the combustion chamber
Stratified charge engine
An internal combustion engine in which a small portion of extremely rich fuel and air is ignited and in turn ignites a much leaner fuel-air mixture. The lean mixture might not fire by itself unless it is ignited by the flame of the burning rich mixture. Its advantage is lower peak combustion temperatures, greater fuel economy, and a decrease in pollutant emissions. The Honda CVCC engine which initiates combustion in a small auxiliary prechamber is one type of stratified charge engine (to be precise, the CVCC should actually be called a dual-combustion engine). Another type is Texaco’s which uses turbulence in the incoming mixture to induce stratification.
A convenient DIY tool for blowing debris from the spark plug recess before plug removal
Straw purchase
This is when a third party buys an automobile and finances it in his name for someone else (who will be the actual driver) because of that other person’s age, bad credit, or lack of credit, etc.
Interfering or disturbing signals of natural origin. The British term is Atomospherics.
A long thin trace of dirt a damaged wiper blade will leave streaks and smears on the windshield
To design the shape of a car body or truck cab so that it reduces air resistance to a minimum
A road within a municipality.

Street bike
A motorcycle which is permitted to be ridden on public roads and must be licensed. In contrast with an off-road bike.
Street car
An electrically driven public transportation vehicle which runs on rails (tracks) inset into the surface of the road and powered by overhead cables. The British term is tram or tram car
Street fighter
A bare bones sportbike, stripped of all extraneous body work also called hooligan bike.
Street rod
  1. A slightly modified rod (car) that will give good day-to-day performance on the streets.
  2. A class of vehicle built before 1950 which has been modified with modern technology, equipment, or refinements and with unlimited modifications to the body
Street version
A detuned version of a vehicle, usually of a racing car
The stress at which material ruptures or fails.

Strength deck
The deck that is designed as the uppermost part of the main hull longitudinal strength girder
Strengthening buttress
  1. Load imposed on an object.
  2. A force causing deformation or strain.
Stress concentration
A condition in which a stress distribution has high localized stresses; usually induced by an abrupt change in the shape of a member (often in the vicinity of notches etc.)
Stress corrosion
Occurs when corrosion causes a highly stressed part (one that is pushed to its maximum tensile strength) to crack. Except for heat treated 400 series stainless, stress corrosion does not normally apply to austenitic stainless, brass, or bronze, since these metals are relatively ductile and not normally used for high tensile operations.
Stress corrosion cracking
(SSC) Cracking due to stress corrosion, a process involving joint corrosion and straining of a metal due to residual or applied stresses
Stress cracking
Damage of parts, especially body panels, subject to constant overload caused by improper mounting; this introduces strain into the panels, causing them eventually to crack
Stressed body
A vehicle body designed so that the outer body panels share a proportion of the total load or stresses in the whole structure instead of the frame taking all the loads. The Jaguar E-Type is one example.
Stressed member
A component that is an integral part of the whole structure
Stress fracturing
Damage of parts, especially body panels, subject to constant overload caused by improper mounting; this introduces strain into the panels, causing them eventually to crack
Stress line
Stress lines
Low areas in a damaged panel, usually starting at the point of impact and traveling outward.
Stress Relieve
Heating to a suitable temperature, holding long enough to reduce residual stresses and then cooling to minimize the development of new residual stresses.
Stress relieving
Even heating of a structure to a temperature below the critical temperature followed by a slow, even cooling.
Stretch bus
A colloquial term for an articulated bus
Stretch limit
The extent to which a KERR rope will stretch before it is in danger of breaking. A guide for the Marlow Ropes Recovaline is 40% stretch; this limit should never be approached.
Stretch limo
A colloquial term for a limousine that has been lengthened to provide extra seating and more legroom
Metal plate fastened to frame and into which the bolt of a latch or lock slides.
The mating part of door lock or hood latch mechanism which is secured to the body; the striker itself has no mechanism and provides only the anchor for the door or hood latch; typical strikers are stud or U-shaped.
Striker plate
An anchor plate to which the striker is attached
Striking blow
A dent removal technique in which the hammer does not hit the panel straight on but is drawn to one side on hitting the surface, thus spreading the impact over a larger area
A thin length of twisted fiber.
A fore-and-aft girder running along the side of a ship at the shell and also to the outboard strake of plating on any deck.

Stringer bar
The angle connecting the deck plating to the shell plating or to the inside of the frames. The strength deck stringer bar is usually called the gunwale bar
  1. Area used for drag racing.
  2. Removing tires and wheels, battery, Hubcaps and other items of value as done by thieves.
  3. To remove the insulation from a wire.
  4. To tear off or break the thread from a screw, bolt, etc., or the teeth from a gear.
Striping tool
A tool used to apply paint in long narrow lines.
Stripped down
Stripper bolt
Discarded term for a shoulder screw.

Stripper/crimper tool
Stripping stock
Rubber stock used to extend the wing of tread rubber when retreading a tire.
Strobe lamp
A colloquial term for a Stroboscope
Strobe light
A colloquial term for a Stroboscope
Stroboscopic ignition timing
  1. The distance the piston moves when traveling from Bottom dead center (BDC) to Top dead center (TDC) or vice versa.
  2. To modify the stroke of an engine by using a different crankshaft to increase or (rarely) reduce the displacement.
Stroke engine
The action of lengthening the stroke on an engine. Sometimes an engine manufacturer will produce an identical engine as he did in the previous year, but this time the stroke is longer. Thus it has been stroked. If the bore is also increased, it is bored and stroked.
Stroked crankshaft
A crankshaft, either a special new one or a stock crank reworked, that has the connecting rod throws offset so that the length of the stroke is increased.
An engine using a crankshaft that has been Stroked.
A method for increasing the displacement of an engine by lengthening the crankshaft throws so that the piston stroke is increased. The crankshaft throws were remachined off center to alter the stroke.

Stroking seal
A disc brake hydraulic seal that is set in a piston groove and moves in the caliper bore with the piston.
Stromberg carburetor
A type of variable venturi carburetor
  1. An automobile that is in great demand and returns good profit to a dealer
  2. A sales person who is aggressive or pushy.
Structural part
Any part of a vehicle that plays a role in ensuring the rigidity and integrity of the vehicle as a whole and that, if it collapses, could make the vehicle unsafe
Structure component
Structure Machine Screws
A Flat Head Machine Screw with one included angle approximately 100 degrees. Usually made in slotted and recessed head types. With a ‘grip’ or unthreaded body at the head.
  1. A single, self contained pivoting suspension unit that integrates a coil spring with a shock absorber. Struts are used on front wheel drive automobiles.
  2. A structural member, especially as part of a framework, used to stiffen, give strength or carry weight.
  3. A bar that connects the lower control arm to the car frame; used when the lower control arm is attached to the frame at only one point.
  4. A Air strut, Chapman strut, Damper strut, Gas prop.
Strut bar
Another name for sway bar or Anti-roll bar.
Strut rod
Strut tower
Abbreviation for Service Throttle System lamp
Stub axle
Stub AxleStub Axle

A short axle that carries one of the front wheels and has limited angular movement about a kingpin

Stubby screwdriver
A screwdriver with a short handle and blade for reaching into confined spaces. In Britain it is called a chubby screwdriver
  1. A metal rod or shaft with threads on both ends. Similar to Grub screw which has uniform thread throughout, while the stud has an unthreaded part in the middle
  2. Metal spikes installed in snow tires to increase traction on ice and hard-packed snow. Studded tires have been banned in many areas because of the damage they inflict upon road surfaces.
  3. A bolt projecting from a plate, like a wheel stud.
  4. A threaded rod. It may be threaded at both ends or continuous.
StudebakerClick image for books on

A vehicle brand of which the following models are classic cars:

  • 1928 8, FA, and FB President
  • 1929-33 President except Model 82

The following models are milestone cars:

  • 1963-64 Avanti
  • 1962-64 Gran Turismo Hawk
  • 1947-49 Starlight Coupe
  • 1953-54 Starliner Hardtop (Six and V-8)
  • 1955 President Speedster
Studded tire
Studded tireStudded tire

A tire (usually a Mud and snow tire) into which small metal studs are embedded. Although it provides better traction on ice and hard-packed snow, its use is illegal in some parts of North America because the studs tend to score the roads.

Stud end
The opposite end of a stud to the nut end
Stud extractor
A tool like a socket wrench for the removal (and installation) of studs
Stud hole
A hole in a wheel through which the wheel studs pass
Stud puller
A tool used to install or remove studs.
Stud remover
A tool like a socket wrench for the removal (and installation) of studs
Stuffing box
Stuffing-box packing
A sealing element of a stuffing box consisting of rings of tissue (e.g., cotton) or metal rings
A driveability-related problem similar to but more severe than Hesitation.


StutzClick image for books on

A vehicle brand of which the 1925-1948 models are classic cars.

Abbreviation for Suction throttling valve
Styled steel wheel
Styled steel wheelStyled steel wheel

A one-piece wheel similar to a stamped-steel wheel, but the visible center section does not require a wheel cover. Sometimes called a mag wheel, however that term properly belongs to magnesium wheels.

Styleside truck
Ford’s term for a pickup truck style in which the side of the bed blends smoothly with the doors and fenders.
Styling kit
A colorless, toxic liquid with a strong aromatic aroma. Insoluble in water, soluble in alcohol and ether; polymerizes rapidly; can become explosive. Used to make polymers and copolymers, polystyrene plastics, and rubber.
SubaruClick image for books on

A model of automobile manufactured in Japan by Fuji Heavy Industries, Ltd. Includes

  • B9 Tribeca (2006-07)
  • Baja (2003-06)
  • DL (19__-89)
  • Forester (1998-2007)
  • GL (1971-94)
  • GL-10 (19__-89)
  • Impreza (1993-2008)
  • Justy (1987-94)
  • Legacy (1990-2008)
  • Loyale (1990-94)
  • Outback (2000-08)
  • RX (19__-89)
  • SVX (1992-97)
  • XT (1985-91)
  • XT6 (1988-91)
An assembled unit designed to be fitted to a larger unit of which it is a component; e.g., the steering gear and front suspension or the final drive and rear suspension
A passenger car containing less than 109 cubic feet of interior passenger and luggage volume. A designation no longer used because even full-size cars are now about the size of what was the compact car. In 1970, for instance, a Chevrolet Impala was a full-size car, a Chevelle was an intermediate, a Nova was a compact. When cars smaller than the Nova came out (i.e., Chevette), they were called sub-compacts.
Cooling of liquid refrigerant below its condensing temperature.
Sub frame
A partial frame that is sometimes bolted to the chassis of unit-body cars. It can be used to support the engine, transmission and suspension instead of having these components directly connected to the main body structure. This more expensive design generally results in better road isolation and less harshness.

Any auxiliary framework attached to the main body of a vehicle. On a motorcycle this often refers to the rear section of the frame, which supports the seat

The top surface of completed earthwork on which the subbase, base, surfacing, pavement or a course of other material is to be placed.
Subgrade stabilization
Excavating and disposing of unstable materials and replacing them with more stable materials.
Condition where a substance changes from a solid to a gas without becoming a liquid.
A sliding under the lap belt in a frontal collision
A subsidiary is an organization operating in a particular country that is owned or controlled by a foreign company which may or may not manufacture in that country.
Subsidiary petal
A secondary petal of a dual-stage reed valve. Opposite of main petal
Subsidized lease
A subvented lease is a lease offered by manufacturers with special incentives to make it more attractive. Special incentives often take the form of a lower base interest rate, higher residual values, and manufacturer discounts. In many cases, a subvented lease will have a lower net interest rate than other leases. Subvented leases are usually only available for a limited time and the terms are not negotiable. Any negotiated change in the terms will result in a different net interest rate.
Typically a group of stacked fuel cells that makes up the base repetitive unit number of cells per full stack. Sub stacks may form an intermediate step in manufacturing and may be used to test new stack concepts prior to scale-up to full size stacks.
Any form of matter or material.

  1. A switching, transforming, or converting station which is found between the generating station and the low-tension distribution network.
  2. The apex of a subsidiary triangle in a survey skeleton
The surface that is to be finished (painted). It can be anything from an old Finish or Primer to an unpainted surface.

An Underbody structure
A throttle valve, mounted ahead of the main throttle valve in the intake tract, that controls airflow into the engine during Toyota Supra traction control system operation.
SuburbanClick image for books on

A model of full-size truck-van produced by the Chevrolet division of General Motors from 1935 to 2008

Subvented lease
A subvented lease is a lease offered by manufacturers with special incentives to make it more attractive. Special incentives often take the form of a lower base interest rate, higher residual values, and manufacturer discounts. In many cases, a subvented lease will have a lower net interest rate than other leases. Subvented leases are usually only available for a limited time and the terms are not negotiable. Any negotiated change in the terms will result in a different net interest rate.
SU carburetor
A widely used type of variable venturi carburetor in Britain. It was named after Skinners’ Union, a long-established manufacturer of variable venturi carburetors the first SU carburetor was patented in 1905 by George Herbert Skinner who went on to found a company with his two brothers to manufacture SU carburetors
Suction chamber
The space above the piston in the piston chamber of a variable venturi carburetor
Suction cup
Suction cupSuction cup

A round object with a concave side which, when pressed against a flat surface, will displace the air within the concave and will cause the suction cup to adhere to the surface.

Suction cup dent puller
Dent PullerDent Puller

A tool for removing dents from a panel. Also called Vacuum suction cup