JEEP WILLYS L4-134 Engine Block "REINFORCED UNLEADED"

L4-134 Go-Devil Engine Block — Reinforced Unleaded

New production to original specifications — Universal for chain and gear drive

★ This is an exclusive new production based on years of study of original Willys blocks. The block is specially reinforced for modern unleaded petrol and combines original dimensions with improved material properties. The universal design makes this block suitable for both military and civilian applications.

⚠ Important

• Assembly only by experienced professional engine builders
• Due to tolerance differences, minor adjustments may be necessary during assembly
• Check before assembly that all components (camshaft, oil pump, timing cover) correspond with chain or gear drive
• Use only the prescribed tightening torques: cylinder head nuts 83-90 Nm, crankshaft bearing nuts 90-96 Nm

Application

This engine block is suitable for vehicles fitted with the Willys L4-134 Go-Devil engine. Due to the universal design, it can be built up with either chain drive (as used in military applications and early civilian jeeps) or gear drive (later civilian production). Note: the choice between chain or gear also determines the necessary oil pump, camshaft retaining plate and timing cover.

Installation notes

This block may only be assembled by experienced professional engine builders. Due to tolerance differences between production runs of components, minor adjustments may be necessary during assembly. The block is supplied with pre-fitted valve guides; these need not be readjusted unless wear occurs. All machined surfaces are milled to original design specifications.

Compatibility

The distinction between chain and gear drive is critical: early blocks had chain drive, where the camshaft rotates in the opposite direction to gear drive. This requires an adapted oil pump drive gear. This universal block is prepared for both systems through the presence of both 3/8" flanged plugs and 1/8" NPT jets. Select the correct components (oil pump, timing chain or gears, timing cover) appropriate to your application.

Historical context

The Willys L4-134 Go-Devil engine was developed by chief engineer Delmar 'Barney' Roos and was the most powerful engine in the prototypes evaluated by the U.S. Army for the standard 1/4-ton jeep. With 60 bhp at 4000 rpm and 105 lb-ft torque at 2000 rpm, the engine exceeded the Army specification of only 85 lb-ft at the rear axle, making the engine the chosen powertrain for hundreds of thousands of jeeps between 1941 and 1945.