Willys-Overland produced cars under the Willys-Knight brand from 1914 to 1933. Most innovative was the double-sleeve engine, patented by Charles Knight, which powered these cars, both four- and six-cylinder models. Rather than conventional valves the design featured two close-fitting sleeves around each piston that moved up and down opening and closing intake and exhaust ports. It was an exceptionally smooth engine and as carbon built up tolerances tightened for even more efficiency and less oil consumption. In 1926 the Willys-Knight Model 66 featured a 66-horsepower, 237 cubic-inch double-sleeve engine and sold for $1,845.
