Engines
Four Cylinder Engines
L134 "Go Devil" Engine
The Willys L134 engine was used in the CJ2, CJ2a and the CJ-3A. Actually the L134 was used in the Willys MB which started production in 1941 for the
Military. When the CJ-3A stopped production in 1953 that was the end of the L134.
The L134 was a 4 cylinder that produced 60 horsepower and was nicknamed the “Go Devil”. While the majority of automotive engines have the valves in the head, this engine was an L-Head design. That meant the valves were in the engine block. The L head engine is also known as a Flat Head Engine. A Flat Head engine can be identified by the absence of a valve cover over the engine head.
- Bore - 3 1/8 inches
- Stroke - 4 3/8 inches
- Compression - 6.48:1
- Horsepower - 60 at 4000 rpm
- Torque - 105 ft-lbs at 2000 rpm
F134 "Hurricane" Engine
Willys-Overland started using the F134 engine in the Jeepster in 1950. This engine was too tall to be used in the CJ3a so in 1953 Willys came out with the CJ3b with a higher hood to accommodate the taller F134 engine. The F134 was also used in the CJ5 and CJ6 until 1971.
The F134 engine was based on the L134. The L134 engine has all the valves in the engine block. The valves, spark plugs and much of the combustion chamber were off to the side of the pistons on the L134. This gave the L134 low compression. The L134 was redesigned by moving the intake valves up on top of then engine in the head. This redesigned engine was the F134.
It is a common misunderstanding that the F-head engine is short for Flat Head engine. This is incorrect. The F134 engine is not a Flat Head engine. The F designation comes from the shape of the intakes. Unlike the L134 the F134 has the intake in the head and the exhaust ports in the engine block. The ports coming into the combustion chamber at 2 different heights gives an F shape (you have to use your imagination). This F Head engine design is very uncommon. Older engines often used a flat head design such as the L134. Newer engines use overhead cams. The F134 was built during the transition from flat head design to OHV design. The F134 has intake valves in the head and exhaust valves in the engine block.
- Bore - 3 1/8 inches
- Stroke - 4 3/8 inches
- Compression - 6.9:1
- Horsepower - 72
Perkins Diesel
From
1961 to 1965 the Perkins Diesel was used in some of the CJ5 and CJ6 Jeeps. This four cylinder was a British made engine. It is a very rare engine for the CJ. Less than 300 Jeeps had this engine installed.
- Displacement - 192 Cubic Inches
- Bore - 3.5 inches
- Stroke - 5 inches
- Compression - 16.5:1
- Horsepower - 58
- Torque - 143
GM 151 cid
The 151 Cubic Inch GM Iron Duke was made by Pontiac from 1977 to 1993. It was only
offered in CJs from ’80 to ’83. Even for a four cylinder the Iron Duke was not too powerful. The Iron Duke used a standard GM bell housing bolt pattern. Since the
Transmissions of these jeeps used a ford bolt pattern the bell housing could be used as a GM engine to Ford transmission adapter. In theory you could bolt a GM V8 in place of the Iron Duke. The problem is the Iron Duke always had a weak transmission behind it that can’t really hold up to any V8.
Unlike the AMC 150 four cylinder engine, the iron duke has the intake on one side and the exhaust on the other. When installed in a CJ the Iron Duke had a Rochester two barrel carburetor.
- Bore - 4.0 inches
- Stroke - 3.0 inches
- Displacement - 151 CI (2.5L)
- Compression Ratio - 8.2:1
- Horsepower - 82
- Torque - 125
- Main Bearings - 5
AMC 150 cid
When AMC bought the Kaiser Jeep company the four cylinder engine installed in the CJ was the GM Iron Duke. AMC decided it would be better to make their own four cylinder. The AMC 150 (2.5L) four cylinder engine was made from the AMC 258 strait 6.
The AMC 150 was used in the Jeep CJ7 from 1984 to 1986.
The AMC 150 has the intake and the exhaust on the left side of the engine. The 150 used a carburetor until 1986.That year the 150 received throttle-body fuel injection.
This AMC 150 belongs to Fatbook from Jeepforum.com
Notice how the AMC 150 has the intake and exhaust on the left side of the engine.
- Bore - 3.88 inches
- Stroke - 3.19 inches
- Displacement - 150.4 CID (2,464 cc)
- Valvetrain - eight overhead valves
- Main bearings - five
- Compression ratio - 9.2:1
Isuzu C240 Diesel
Some CJ7s from 1980 through 1982 came with the Isuzu C240 Diesel four cylinder engine. These engines were built at a General Motors factory in Ohio (GM owns Isuzu). These Isuzu powered CJ7s were built for export only. The C240 Diesel was mated to the T176 transmission.
- Bore – 3.39 inches
- Stroke – 4.02 inches
- Displacement – 144 CI
- Compression - 20:1
Six Cylinder Engines
“Dauntless” Buick 225 V6 Engine
The Dauntless V6 engine was used in some CJ5's and CJ6's from 1966 to 1971. It is called an “odd fire” V6. It is a 90 degree V6 that is basically a V8 with 2 cylinders removed. Because the crankshaft was not changed to even out the rotation of the cylinders this V6 this engine has a distinctive rumble.
The 225 has 3 main bearings.
- Bore – 3.75 inches
- Stroke – 3.4 inches
- Compression – 9:1
- Horsepower - 160
AMC 232 Straight Six
When AMC bought Kaiser Jeep in the early '70s AMC made some changes to the CJ model line. The most important change was to lengthen the hood 3 inches in 1972. This was done to install the longer AMC engines. In 1972 the standard engine was the AMC 232. It was available until 1979. The 232 strait 6 produced much less horsepower than the Dauntless V6.
The 232 has 7 main bearings.
- Bore: 3.75"
- Stroke: 3.5"
- Displacement: 232/3802 (cu in/cc)
- Compression Ratio: 8.0:1
- Main Bearings: 7
- Net Horsepower: 100 @ 3600 rmp
- Net Torque: 185lb/ft @ 1800 rpm
- Carb: 1bbl
- Intake Valves:
- Head dia: 1.787"
- Lift: 0.372"
- Exhaust Valves:
- Head dia: 1.406"
- Lift: 0.372
AMC 258 Straight Six
The AMC 258 was based on the 232. The stroke was increased to bring the displacement to 258 cubic inches. The 258 has a reputation of a strong, torquey, reliable motor. The 258 has 7 main bearings.
- Bore: 3.75 inches
- Stroke: 3.9 inches
Compression: 8.3:1 (after '82 compression was 9.2:1)
- Bore: 3.75"
- Stroke: 3.90"
- Displacement: 258/4299 (cu in/cc)
- Main Bearings: 7
- Net Horsepower: 110 @ 3500 rmp
- Net Torque: 195lb/ft @ 2000 rpm
- Carb: 1bbl
- Intake Valves:
- Head dia: 1.787"
- Lift: 0.372"
- Exhaust Valves:
- Head dia: 1.406"
- Lift: 0.372
V8 Engine
AMC 304 V8
Once AMC bought the Kaiser Jeep Company the CJ engine compartment was lengthened 3 inches to accommodate the six and 8 cylinder engines. The AMC 304 V8 was used as an option in CJs from 1972 to 1981.
The AMC 304 was the only V8 used in any CJ but all the AMC V8s such as the 304, 360, 390 and 401 use the same engine block. The only difference is the bore and stoke. The accessories will all bolt up the same. The transmission and engine mounts are the same. This makes swapping out the AMC 304 in favor for another AMC V8 easy.
- Bore: 3.75"
- Stroke: 3.44"
- Displacement: 304/4983 (cu in/cc)
- Compression Ratio: 8.4:1
- Main Bearings: 5
- Net Horsepower: 150 @ 4200 rmp
- Net Torque: 245lb/ft @ 2500 rpm
- Carb: 2bbl
- Intake Valves:
- Head dia: 1.787"
- Lift: 0.425"
- Exhaust Valves:
- Head dia: 1.406"
- Lift: 0.425"
