Letter J – Dictionary of Automotive Terms
- To lift a vehicle off the ground in order to effect repairs
- To steal a vehicle
- A characteristic of swing-axle Rear suspensions. cornering forces can act on these suspensions to lift the body of the vehicle so that the outer wheel tucks or jacks under the vehicle. When carried to the extreme, jacking forces could tip the vehicle over.
- A device for lifting the vehicle, or part of the vehicle, off the ground to facilitate repairs.
- Jack knife
- The action of a vehicle (tractor) with a trailer in which the trailer and the vehicle form a V instead of normally being pulled in a straight line. Usually this is the result of a Skid in which the trailer swings around dangerously and tries to overtake the cab.
- Skidding of an articulated vehicle sometimes results in rotation at the articulation (hitch) point so that the tractor is rotated against the trailer in a manner similar to the closing of a jackknife.
- To place the trailer at a very sharp angle to the tractor.
- Jack stand
A safety device that keeps the vehicle from falling to the ground if the lifting jack is removed or faulty. Most jobs require two jack stands for safety. Also called an Axle stand or Safety stand
- Jack up
- To raise using a Jack
- Jacking point
- A strengthened place on the underbody to put the jack. Small cars have one point on each side but larger cars may have two
A vehicle brand produced by Jaguar Cars Limited of which the 1946-48 2.5 Litre and 3.5 Litre Mark IV, but not 4-cyl. models are classic cars. The 1957-64 3.4/3.8 Sedans are milestone cars. Includes 1½ Litre saloon (1935-1949), 2½ Litre saloon (1935-1948), 3½ Litre saloon (1937-1948), 240 (1966-1968), 340 (1966-1968), 420 (1966-1968), 420G (1966-1970), E-Type (1961-1974), Mark 1 (1955-1959), Mark 2 (1959-1967), Mark V (1948-1951), Mark VII (& VIIM) (1951-1957), Mark VIII (1957-1959), Mark IX (1959-1961), Mark X (1961-1970), S-type (1963-1968, 1999-2008), Vanden Plas (2002-05), X-type (2001-current), XF (2008-current), XJ (X350) (2003-current), XJ6 Series 1, 2 & 3 (1968-1987), XJ6 (XJ40) (1986-1994), XJ6 (X300 & X301) (1995-1997), XJ8 (X308) (1997-2002), XJ8 (1998-2007), XJ12 (1972-1992), XJ12 (XJ81) (1993-1994), XJ12 (X300 & X301) (1995-1997), XJR (1995-2007), XJR-S (1993), XJ-S (1975-1996), XJ Sport (2002-03), XJ Super (2002-07), XK8 (1997-2006), XK (X100) (1997-2005), XK (X150) (2006-current), XK120 (1948-1954), XK140 (1954-1957), XK150 (1957-1961), and XKR (2000-06)
- Jaguar Drophead
- A vehicle brand of which the 1951 Mark V Drophead is a milestone car.
- Jaguar E-type
A model of automobile manufactured by Jaguar in England. The 1961-67 E-Type models are milestone cars.
- Jaguar Mark
A model of automobile manufactured by Jaguar in England. The 1946-48 models with 2.5 Litre, 3.5 Litre Mark IV (not 4-cyl.) are Classic cars. The 1951-54 Mark VII and ’54 Mark VII M models are milestone cars. The 1956-57 Mark VIII models are milestone cars. The 1958-61 Mark IX models are milestone cars. The 1962-64 Mark X models are milestone cars.
- Jaguar XK
A model of automobile manufactured by Jaguar in England. The 1945-54 XK 110 models are milestone cars. The 1954-57 KX 140 models are milestone cars. The 1958-61 XK 150 models are milestone cars.
- Jake brake
- A device which shuts off the exhaust valves manually so that in the exhaust stroke, the burned gasses cannot escape through the exhaust valves. Instead they press against the head of the piston and causes the piston to slow down. When the intake valve opens, some of the exhaust escapes out the intake valve and gives a distinctive loud rapping noise. Jake brakes are used in large truck engines to assist in slowing the vehicle. Many municipal bylaws prohibit the use of jake brakes because of the excessive noise. The most common type is called a Jake Brake because the predominant manufacturer is Jacobs Vehicle Equipment Co. Other types of retarders include exhaust retarders, transmission-mounted hydraulic retarders and axle-mounted electromagnetic retarders. Also called a retarder.
- Abbreviation for Japan Automobile Manufacturers Association
- Jamb switch
- A push-button light switch located in a door jamb (e.g., for courtesy lights, trunk light)
- Jam nut
- A second nut (usually thinner) on a screw or bolt which locks against the first nut (i.e., jams against it) so that the nut won’t come loose.
- A self-locking nut
- Jam on the brakes
- The action of quickly depressing the brake pedal (pulling the brake lever on a motorcycle or bicycle) especially in an emergency situation.
- Jam the brakes
- The action of quickly depressing the brake pedal (pulling the brake lever on a motorcycle or bicycle) especially in an emergency situation.
- English engine manufacturer. Founded in 1903 by John A. Prestwich, the company was bought by Villiers in 1957
- Japanese lantern-type jacket tube
- A web-type jacket tube of a steering column which, on impact, folds like a Japanese lantern
- Japanese Motorcycle
- Honda motorcycle
- Kawasaki motorcycle
- Suzuki Motor Corporation motorcycle
- Universal Japanese Motorcycle
- Yamaha motorcycle
A ‘bent bolt’ having the unthreaded end reverse bent to approximately a semicircle.
An abbreviation for Junction, often seen on road signs indicating the distance to a junction with a specified road, for example ‘Jct I-80 26,’ meaning that it is 26 miles to where this road has a junction with I-80.
- Jeantaud axle and steering
A SUV which was originally manufactured by Willys, then owned by AMC, and now owned by Chrysler. Includes Cherokee (1974-83, 1984-2001, 2002-07), CJ (1944-86), Comanche (1986-92), Comanche Pickup (1986-92), Commander (2006-08), Commando C104 (1972-73), Compass (2007-current), DJ (1955-82), FC (1956-65), FJ (1961-65), Grand Cherokee (1993-98, 1999-2004, 2005-07), Grand Wagoneer (1984-91, 1993), J10 Pickup (1963-88), J20 Pickup (1963-88), Jeepster (1948-50), Jeepster Commando C101 (1966-71), Liberty (2002-current), Patriot (2007-current), Super Wagoneer (1966-69), Wagoneer (1963-83, 1984-90), Wrangler (1987-96, 1997-current), and Willys Jeepster VJ (1948-50)
- Jeep Dolly
- A heavy-duty goose neck dolly usually with two or more axles that support the front of a cradle frame for transporting large objects or a heavy-duty lowboy trailer.
A vehicle brand of which all 1936-39 models except 2 1/4 Litre 1645 are classic cars
- Jerry rigged
- A corruption of the term Jury rigged.
- Jersey barriers
- Preformed concrete dividers that separate traffic or are used in place of guard rails on some routes.
- A small precision-made hole. Often a brass fitting placed inside one of the passages of a carburetor to control the flow of gasoline, air, or air/fuel mixture.
- The nozzle containing such a hole.
- Jet adjuster
- A nut that regulates the volume or strength of the air/fuel mixture in a variable-choke carburetor
- Jet cooling system
- Jet pump is used to produce a vacuum so water or refrigerant may evaporate at relatively low temperatures. These systems usually require large condenser and have a low efficiency to remove heat.
- Jet Cutter
- Jet fuel
- A refined petroleum product used in jet aircraft engines. It includes kerosene-type jet fuel and naphtha-type jet fuel.
- Jet process
- A process by which the thickness of hot-dip galvanized coatings on steel strips can be regulated, allowing the application of coatings of different thicknesses on the two sides of steel strips. When leaving the zinc melting pot, the strip passes two jets through which air, gas, or vapor is directed on the steel strip to remove superfluous zinc. The coating thickness decreases with the strength of the jet
- Items that are thrown overboard from a vessel in distress. Discarded cargo that washes ashore.
The most widely used rim flange type for passenger car wheels; the J-flange is 17.3 mm in height
gate transmission shifterThe center console-mounted transmission shifter in Jaguars. The shifter has the normal pattern down the right side (park, reverse, neutral, low, and drive) while on the left side the driver can select 2nd, 3rd, 4th and 5th manually to have more control over the car. And, no clutch is required.
- See Lift Jib.
- Device used in the accurate machining of good in process by holding the goods firmly and guiding tools exactly to position.
- Abbreviation for Just-in-Time — a manufacturing system which depends on frequent, small deliveries of parts and supplies to keep on-site inventory to a minimum.
A safety wheel which can be run when deflated. Two independently inflated tires are seated on a double rim consisting of two single rims. The JJD wheel has excellent aquaplaning properties; a reliable tire pressure control system is required, however, since a defective tire is not easily detectable
- A particular piece of work.
- Jockey pulley
- Jockey wheel
- A wheel used to maintain tension in a chain or belt.
- A slight step along the edge of a panel to provide a level mounting and welding surface so that it can be overlapped against the adjacent panel for subsequent lap or spot welding.
- To join by means of a joggle
- An abrupt bend or offset in a plate, bar, or frame to eliminate the use of liners.
- A metalworking tool used for creating a Joggle
- The place where two pieces meet when a structure is made of smaller pieces.
- A flexible or firm connector between two rods.
- Connecting point as between two pipes.
- The location at which two adherends are held together by an adhesive.
- Points of connection between heat transfer surfaces; between positive and negative pressure zones within components of the power plant; and between power plant components.
- The intersection and connection of components, often identified by location within the pallet as the end joint, center joint and corner joint.
- Ball And Socket Joint
- Ball joint
- Ball joint rocker arm
- Ball joint steering knuckle
- Bevel joint
- Butt joint
- Cardan joint
- Cast Welded Rail Joint
- Cold solder joint
- Constant velocity joint
- Corner joint
- CV joint
- Doughnut joint
- Dry joint
- Edge joint
- Expansion Joint
- Flange joint
- Half-moon slip joint pliers
- Hardy-spicer joint
- Hardy-spicer universal joint
- Heim joint
- Impact swivel ball universal joint
- Lap joint
- Plunging joint
- Pot joint
- Rzeppa-type joint
- Rzeppa-type universal joint
- Slip joint
- Splined joint
- Spline Joint
- Tripod joint
- Universal joint
- Upper Ball Joint
- Joint boot
- Jointed shaft
- Joint rate
- The common charge for transportation agreed upon by two or more carriers, published in a single tariff, and applying between point on line of one and point on line of another. May include one or more intermediate carriers in route.
- Joint venture
- An international business collaboration between foreign interests and private parties from a host country in which two or more parties establish a new business enterprise to which each contributes and where ownership and control are shared.
- The effect caused by harsh clutch release. The car body jerks repeatedly in a longitudinal direction
- A vehicle brand of which the 1929 – 1931 Models G, 90, Great Line 90, and Speedway Series Z are classic cars.
- (J) The international metric unit of measurement of energy, work, and heat. One joule equals the work done when a force of 1 newton moves a body 1 metre. It is one watt-second. Equivalent to 0.737324 ft-lbs.
- Joule’s Law
- The rate of heat production by a steady current in any part of an electrical circuit that is proportional to the resistance and to the square of the current, or, the internal energy of an ideal gas depends only on its temperature.
- Joule-Thomson effect
- The change in the temperature of a gas on its expansion through a porous plug from a higher pressure to a lower pressure.
- The action of bouncing. When speaking of shock-absorbers, it is the compression stroke while rebound is the opposite.
- Jounce and rebound
- Jounce buffer
- Jounce bumper
- An elastic cushion used to stiffen the suspension gradually as it approaches the end of its Jounce travel. Also called jounce buffer.
- Jounce bumpers
- Elastic cushions used to stiffen the suspension gradually as it approaches the end of its Jounce travel.
- That part of a shaft that is prepared to accept and support a bearing. The area on the crankshaft that fits into the lower portion of the Connecting rod. A layer of oil and metal bearing cushions the impact during the Power stroke to prevent the crankshaft from being crushed by the swiftly descending piston and Connecting rod.
Joint Policy Advisory Committee on Transportation
- Abbreviation for Jet mixture solenoid valve
J-type vent tubes
Special tubes located on the top of marine carburetors that direct any overflow from the carburetor bowl(s) back into the throttle bores. USCG-approved method of preventing fire in the engine compartment of the inlet valve sticks in an open position
- Jubilee® clamp
A trade name for a band clamp to secure a hose around a fitting. Also called a screw clamp. A screw thread pattern is cut into the band (usually stainless steel). One end of the band contains a captive screw. When the screw is turned, it tightens the band around the hose. Made by L. Robinson & Company (Gillingham) Limited
- Jubilee® clip
- Another term for a Jubilee® clamp
- A British term for a very large transport truck (i.e., goods lorry); compare Road train
- Juice brake
- Juice brakes
- A vehicle brand of which models built between 1925 and 1948 are classic cars with required application.
- Jumped time
- A situation in which ignition or camshaft timing is incorrect because of a mechanical malfunction
- A temporary wire leading from one terminal to another
- Jumper cable
- Jumper cables
- Cables used to start a disabled vehicle by conducting electrical current from the battery of one vehicle to another so that the disabled vehicle can be started and begin to generate it own power. The British term is Jump leads
- Jump lead
- British term for Jumper cables or booster cables
- Jump spark
- A high tension electrical current which jumps through the air from one terminal to the other.
- Jump start
- The act of using Jumper cables on a weak battery to start a disabled vehicle.
- A region of transition between semiconductor layers, such as a p/n junction, which goes from a region that has a high concentration of acceptors: (p-type) to one that has a high concentration of donors: (n-type).
- Junk ring
- A flexible ring used in the cylinder head to provide a seal with the inner sleeve of a sleeve valve engine
- Jury rig
- The action of Cobbling something together instead of put together according to Specifications.
- Jury rigged
- Something that is Cobbled together instead of put together according to Specifications. An alteration of the expression, Jewry rigged which was a slur on the Jews to indicate poor workmanship.
- (JIT) refers to the movement of material to the necessary place at the necessary time. It is part of a business philosophy based on achieving excellence in a manufacturing company through the continuous elimination of waste. A manufacturing system which depends on frequent, small deliveries of parts and supplies to keep on-site inventory to a minimum.
- Just-in-time system
- A system of production where components are delivered as they are required rather than keeping them in store
- Juvenile delinquent
- Trucker slang for someone pretending to be a truck driver as in ‘Let’s take it to the double Harley there’s too many juvenile delinquents on this channel.’