The jeepfan.com 1978 CJ had a tired motor. It was running an AMC 360 V8 from a 1970 AMC Ambassador car. This engine has higher horsepower and torque since it was from a time of little or no emission standards. A rebuild on an engine that is still running good enough is a tough decision to make. I thought, do I drive it till it dies? or go for it? Well being somewhat of a motor-head out came the engine.
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I am not new to this but I quickly discovered that an AMC is quite different than a Chevy. Pieces were different and were in a different place. I have found after spending a good amount of time with this AMC now a Chevy motor looks a bit strange.
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Pulling the Motor
After removing the grille, fenders, and hood I began work at disconnecting the wiring and linkages. Make sure you label everything. It wasn’t too long until the drive shafts were out and exhaust was disconnected. Next we ousted the engine, trans, and transfer case all together. After some cleanup I started ripping into the motor.
Engine Evaluation
Very soon I made some disappointing discoveries. It looks like the engine broke a timing chain at one time. I figured this out because I found the composite plastic material that the chain sprockets are made of in the oil pan. I pulled the bearing caps and found the bearings were toast. Since the timing chain drives the cam which drives the oil pump it’s likely the engine ran without oil for a little. It’s hard to know if this caused the damage. In addition it turned out that that 7 pushrods were bent.
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Machine Work
After the engine was completely disassembled I took the block, crank, and rods to a local machine shop. The block was cleaned and bored .020 over, the crank cut .010 under. New pistons were installed on the rods and things were ready to start going back together.
Assembly
The process of assembling an engine shouldn’t be taken lightly. It requires a clean space and patience. Rushing the assembly by skimping on the process or procedure can lead to disaster. We aren’t going to cover the details in assembling an engine here. Assembly began with new rings and bearings leading up to a fresh short block. A valve job was done on the heads and I started ordering some performance items.
An Edelbrock Performer Manifold, Camshaft, and Edelbrock dual roller timing chain were selected and ordered. New push rods and Summit brand roller tip rockers were installed.
Clutch, Fuel Injection and Exhaust
It was almost time for the rebuilt engine to go back into the Jeep. Since the engine was out I installed a new Centerforce clutch and new gaskets on the transmission and transfer case. The transmission and transfer case were reattached to the engine and it was installed back in to the Jeep.
I hooked up all the wiring and plumbing. I installed a Holley 670cfm Pro-Jection which took some effort and time. Some other items were a K&N Air Filter, 2.25in dual exhaust with Dynomax Super Turbo mufflers, and a 3 core radiator.
After the initial tuning stage the results of my long and hard work were evident. The engine was smooth and strong, the fuel injection provided instant starting and solid off-road performance. I now have one less thing to be concerned about when I off-road and am miles away from anything.
