The Chevrolet 350 engine uses a crankshaft located in the bottom of the engine to move power from the pistons to the transmission and the drive wheels. The crankshaft has round portions that are on the same line as the center of the shaft. These portions are surrounded by pieces of metal called main bearing caps or main caps that clamp down on the shaft. There are bearings inside the main caps that allow the crankshaft to spin at thousands of revolutions per minute without wearing out. Sometimes the bearings must be replaced. This is a delicate job.
Remove the engine from your 350 Chevy with a hoist. Set it on an engine stand to hold it while you work on it. Turn the engine upside down.
Use a lint-free cloth to clean the saddles of the block.
Press the half of the engine bearing that goes into the saddle of the engine block in its place. There is a small tang on each bearing and a notch in the saddle. Match these up.
Look for the oil hole in the bearing. It must be directly over the oil supply hole in the saddle.
Look for the thrust bearing. One of the bearings will have special flanges that limit lateral movement of the crankshaft. The flanges need to be coated with oil before the engine is started.
Lube both halves of the bearings with assembly lube
Locate the plastic gauge that came with the bearing kit. Place it on the main bearing. The gauge measures the distance between the crankshaft and the bearing after the main caps are put into position.
Position the crankshaft on the saddles carefully. One half of the bearing is in place in the saddle of the engine block. Place the other half of the bearing on top of the crankshaft journal.
Apply oil to the bolts.
Torque the bolts down on the main caps with the torque wrench to the specification indicated in a shop manual for your 350 Chevy's model-year. The specs may be different depending on the type of main bolts you're using.
Unbolt the main caps and retrieve the plastic gauge. Use the instructions from the bearing kit to read the results.
Replace the main caps if the clearance is correct and tighten the bolts down with the torque wrench.
