Willys Go Devil engine

In 1940, the Willys Quad was built to compete against the Bantam reconnaissance car for evaluation by the U.S. Army.[2] The two prototype Quads were powered by the Willys “Go-Devil” engine that turned out to be the automaker's greatest asset.[2] Willys' pilot vehicle was overweight compared to the Army's requirements, but the "Go Devil" engine rated at 55 hp (41 kW; 56 PS) included a heavier transmission, a combination that proved to be beneficial in the long-run for use in cross-country travel.[3]

The engine was developed by Willys' Chief Engineer, Delmar "Barney" Roos, and was the most powerful of the three prototype vehicles evaluated by the U.S. Army for production.[4] Roos took the "less than impressive" 48 hp (36 kW; 49 PS) automobile engine and increased its performance and durability.[5] The specifications by the Quartermaster Corps called for only 85 lb⋅ft (115 N⋅m) of torque at the rear axle.[5] The extra power made it the engine of choice for the U.S. Army.[5]

The engine displacement was 134.2 cu in (2,199 cc) with a 3.125 in (79.4 mm) bore and 4.375 in (111.1 mm) stroke, a very undersquare design. It was an L-head design, with valves parallel with the cylinders. Initial power output was 60 hp (45 kW; 61 PS) at 4000 rpm and 105 lb⋅ft (142 N⋅m) of torque at 2000 rpm with 6.48:1 compression.[4]

The L134 was phased out by the F-head Willys Hurricane engine beginning in 1950.

• 1937–1942 Willys Americar
• 1941–1945 Willys MB
• 1941–1945 Ford GPW
• 1944–1945 Willys-Overland CJ-2
• 1945–1949 Willys-Overland CJ-2A
• 1946–1950 Willys Jeep Station Wagon in which it was rated at 63 hp (47 kW; 64 PS)[6]
• 1949–1953 Willys-Overland CJ-3A
• 1948–1950 Willys-Overland Jeepster
• 1950–1952 Willys M38
• 1950–1954 Henry J
• 1952–1954 IAME Rastrojero
• 1956–1965 Willys DJ-3a
• 1956–1965 Hotchkiss M201 (Willys MB produced under licence in France)