Jeep CJ 1945-1970 Repair Information

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4-134 L-HEAD ENGINE



The model L4-134 engine is an L-head 4-cylinder engine. The cylinder block and crankcase are cast integrally. Both intake and exhaust valves are mounted in the cylinder block with through water jacketing to provide effective cooling. The valves are operated by conventional valve tappets. The engine is equipped with a fully counterbalanced crankshaft supported by three main bearings. To better control balance, the counterweights are independently forged and permanently attached to the crankshaft with dowels and capscrews that are tack welded. Crankshaft end-play is adjusted by shims placed between the crankshaft thrust shims placed between the crankshaft thrust washer and the shoulder on the crankshaft.

Aluminum pistons, forged steel connecting rods, and replaceable main and connecting rod bearings are used in this engine. The camshaft on current production engines is gear driven from the crankshaft (chain driven on early production engines).

The water pump is mounted on the front of the cylinder block, and is belt driven by the crankshaft. Circulation of the coolant is controlled by a thermostat installed in the water outlet which is mounted on top of the cylinder head.

The engine is pressure lubricated. An oil pump, gear driven by the camshaft, is mounted externally on the left side of the crankcase. The pump forces the lubricant through oil channels and drilled passages in the crankshaft to efficiently lubricate the main and connecting rod bearings. Lubricant is also force fed to the camshaft bearings and timing gears. Cylinder walls and piston pins are lubricated from spurt holes in the "follow" side of the connecting rods.

The carburetor is mounted on top of the intake manifold. The intake and exhaust manifolds are mounted on the left side of the cylinder block. A thermostatically controlled valve in the exhaust manifold controls the temperature of fuel/air mixture in the intake manifold.

4-134 F-HEAD ENGINE



The F4-134, 4-cylinder engine is of a combination valve-in-head and valve-in-block construction. The intake valves are mounted in the head and are operated by pushrods through rocker arms. The intake manifold is cast as an integral part of the cylinder head and is completely water jacketed. This type of construction transfers heat from the cooling system to the intake passages and assists in vaporizing the fuel when the engine is cold. Therefore, there is no heat control valve (heat riser) needed in the exhaust manifold.

The exhaust valves are mounted in the block with thorough water jacketing to provide effective cooling of the valves.

The engine is pressure lubricated. An oil pump which is driven by the camshaft forces the lubricant through oil channels and drilled passages in the crankshaft to efficiently lubricate the main and connecting rod bearings. Lubricant is also force fed to the camshaft bearings, rocker arms, and timing gears. Cylinder walls and piston pins are lubricated from spurt holes in the "follow" side of the connecting rods.

The circulation of the coolant is controlled by a thermostat in the water outlet elbow which is cast as part of the cylinder head.

The engine is equipped with a fully counterbalanced crankshaft that is supported by three main bearings. The counterweights of the crankshaft are independently forged and are permanently attached to the crankshaft with dowels and cap screws that are tack welded. Crankshaft end-play is adjusted by placing shims between the crankshaft thrust washer and the shoulder on the crankshaft.

The pistons have an extra groove directly above the top ring which acts as a heat dam or insulator.

The engine was available in compression ratios ranging from 6.3:1 to 7.8:1, which permits the use of regular octane gas.

The displacement of the F4-134 engine is 134.2 cu. in. (2199.5cc).

V6-225 ENGINE



The V6 engine has a displacement of 225 cu. in. (3687.75cc) and a compression ratio of 9.0:1, which permits the use of regular octane gas.

The engine is designed with two banks of three cylinders each. The banks of cylinders are opposed to one another at a 90 degree angle. The left bank of cylinders, as viewed from the driver's seat, is set forward of the right bank so that the connecting rods of opposite pairs of pistons and rods can be attached to the same crank pin.

The crankshaft counterbalance weights are cast as an integral part of the crankshaft. All of the crankshaft bearings are identical in diameter, except for No. 2 bearing which is the thrust bearing. It is larger than the rest.

The cast iron heads are interchangeable. The camshaft, which is located above the crankshaft, between the two banks, operates hydraulic valve lifters. The rocker arms are not adjustable.

6-226 L-HEAD ENGINE



This Kaiser-built engine is used in the Utility Series trucks. It is of the valve-in-block, or flat head, design. The head and block are cast iron. With this arrangement, there are no moving parts in the cylinder head. The crankshaft is supported by four main bearings.

6-230 ENGINE



The overhead camshaft 6-230, built by the Continental Engine Corp. was a fairly radical design for its day, incorporating features found in more modern engines. The camshaft is equipped with only six lobes, with the same camshaft lobe operating both intake and exhaust valves on each cylinder. The cylinders and crankcase are integrally cast, forming a rigid unit. The fully balanced crankshaft is supported by four, unusually large, main bearings. The cylinder head employs a cross-flow design with hemispherical combustion chambers.

 
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