Willys (Willys-Overland) Willys-Knight History

After John North Willys licensed Charles Yale Knight's sleeve-valve engine, the Willys-Knight debuted in 1914 as the company's upmarket line. The sleeve-valve design ran quietly and smoothly, with no poppet valves or valve springs, and Willys-Overland advertised it as 'the only engine that improves with use' — a claim that was largely true, as carbon deposits on the sleeves actually raised compression.

Early Willys-Knights were fours (a sleeve-valve V8 was offered briefly 1917–1919); from 1925 the line was built around inline sixes. The best-known was the Great Six, sold 1925–1933 in a series of Model 66 variants, culminating in the 1933 66E Great Six.

Willys-Knight averaged around 50,000 cars a year through the 1920s and was by far the most successful American sleeve-valve marque. The Depression and Willys-Overland's 1933 reorganization ended the line — the 1933 Willys-Knight 66E was the last sleeve-valve car built in America.