Willys Go Devil engine

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Go Devil
Willys MB (Bild 6 2008-06-14) Motor.JPG
Displacement134.2 cu in (2.199 L)
Cylinder bore3.125 in (79.4 mm)
Piston stroke4.375 in (111.1 mm)
Block materialIron
Head materialIron
Compression ratio6.48:1
Fuel system1-barrel carburetor
Fuel typeGasoline
Cooling systemWater-cooled
Power output60 hp (45 kW; 61 PS)
Specific power0.42 hp/CID
Torque output105 lb⋅ft (142 N⋅m)
SuccessorWillys Hurricane engine

The Willys L134 (nicknamed Go Devil) is a straight-4 automobile engine that was made famous in the Willys MB and Ford GPW Jeep produced during World War II. It powered nearly all the Jeep vehicles built for the U.S. and Allies.[1] It was later used in a variety of civilian Jeep vehicles.


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 to 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.



  1. ^ "Willys-Overland Jeep advertisement". Life. 14 (7): 13. 15 February 1943. Retrieved 23 November 2014.
  2. ^ a b Doyle, David. Standard Catalog of U.S. Military Vehicles (Second ed.). KP Books. p. 28. ISBN 9780873495080. Retrieved 23 November 2014.
  3. ^ Zaloga, Steven J. (2005). Jeeps 1941-45. Osprey Publishing. pp. 8–9. ISBN 9781841768885. Retrieved 23 November 2014.
  4. ^ a b Statham, Steve (1999). Jeep Color History. Motorbooks. p. 24. ISBN 9780760306369. Retrieved 23 November 2014.
  5. ^ a b c Green, Michael; Stewart, Greg (2005). Humvee at War. Zenith Press. p. 13. Retrieved 23 November 2014.
  6. ^ Allen, Jim (2003). Jeep Collector's Library. Motorbooks, MBI Publishing. p. 227. ISBN 9780760314869. Retrieved 23 November 2014.

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