AMC Coupes/Sedans/Wagons 1975-1988 Repair Information



4-121 ENGINE

See Figures 1 and 2

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Fig. Fig. 1: Exploded view of the block assembly4-121 engine

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Fig. Fig. 2: Exploded view of the cylinder head components4-121 engine

During the 1977 model year, a four cylinder 2 liter (121 CID) engine, manufactured by Volkswagen, was introduced for the Gremlin. The engine is of overhead camshaft design, belt driven from the crankshaft. The cylinder head is cast aluminum alloy and has removable camshaft bearing caps. Valve lash is controlled by manual adjustment of a tapered adjusting screw, located at the base of the tappet, under the camshaft. The intake and exhaust manifolds are on the opposite sides of the cylinder head. The block is of cast iron and the crankshaft is set into five main bearings. Three grooved aluminum alloy pistons are used with full floating piston pins. The oil pump is located at the front of the block and is driven by the crankshaft.

4-150 ENGINE

The 4-150 engine was first used in 1984 models, replacing the 4-151, is a new design, developed from existing technology at work in the venerable 6-258. It is a four cylinder, overhead valve configuration with cast iron head and block. The crankshaft rides in 5 main bearings. Both manifolds are on the left side of the engine. The engine is thoroughly conventional in all respects.

4-151 ENGINE

See Figures 3 and 4

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Fig. Fig. 3: Block assembly component locations 4-151 engine

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Fig. Fig. 4: Exploded view of the cylinder head4-151 engine

Beginning in 1980, the 151 cubic inch engine, manufactured by Pontiac, replaced the 121. The 151 is an inline 4-cylinder engine with a cast iron cylinder head and block. The pistons are made of light weight cast aluminum. The cylinder head is of a crossflow design for more efficient combustion. The cam shaft, gear driven by the crankshaft, operates the overhead valves through hydraulic lifters and pushrods.

6-232 AND 258 ENGINES

See Figures 5 and 6

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Fig. Fig. 5: Cylinder head components6-232 and 258 engines

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Fig. Fig. 6: Exploded view of the cylinder block6-232 and 258 engines

The 232 and 258 sixes are virtually identical in construction. The design was originally adopted in 1966 and has remained unchanged. They employ a cast iron cylinder head and block and are long stroke cycle, giving them a good torque curve for low end power. The engines are overhead valve with a seven main bearing crankshaft.

8-304, 360 AND 401 ENGINES

All the AMC V8s are similar in design, having five main bearing crankshafts and overhead valves with hydraulic lifters. The head and block are cast iron.