Chevrolet 14088526 Engine Crankshaft

Remove all burrs from the crankshaft oil holes with a stone, file or scraper, chamfering the oil holes to remove sharp edges that might gouge or scratch the new bearings. Clean the crankshaft with solvent and dry it with compressed air, if available. Be sure to clean the oil holes with a stiff brush and flush them with solvent. Wear eye protection when using compressed air. Check the main and connecting rod bearing journals for uneven wear, scoring, pits and cracks. Also, check the rest of the crankshaft for cracks and other damage. Rub a penny across each journal several times. If a journal picks up copper from the penny, it's too rough and must be reground. If the seals have worn grooves in the crankshaft journals, or if the seal journals are nicked or scratched, the new seal(s) will leak. The crankshaft should be magnafluxed to reveal hidden cracks-an automotive machine shop will handle the procedure. Using a micrometer, measure the diameter of the main and connecting rod journals and compare the results to the Specifications. By measuring the diameter at a number of points around each journal's circumference, you'll be able to determine whether or not the journal is out-of-round. Take the measurement at each end of the journal, near the crank throws, to determine if the journal is tapered. If the crankshaft journals are damaged, tapered, out-of-round or worn beyond the limits given in the Specifications, have the crankshaft reground by an automotive machine shop. Be sure to use the correct size bearing inserts if the crankshaft is reconditioned. Examine the main and rod bearing inserts.

The main bearing caps should be checked to see if they're marked to indicate their locations. They should be numbered consecutively from the front of the engine to the rear. If they aren't marked, they should be marked with number stamping dies or a center punch.

If the seals have worn grooves in the crankshaft journals, or if the seal journals are nicked or scratched, the new seal(s) will leak.

Before removing the main bearing cap bolts, take care to lay them out in the correct order for proper installation.

The main bearing caps should be checked to see if they're marked to indicate their locations. They should be numbered consecutively from the front of the engine to the rear. If they aren't marked, they should be marked with number stamping dies or a center punch.

If the old bearing inserts are still in place, remove them from both the block and the main bearing caps.

Check the main bearing oil clearance using Plastigage, ensuring it is placed parallel to the journal axis without covering oil holes.

If the endplay exceeds specifications, inspect the thrust surfaces for wear. If no wear is found, new main bearings may resolve the issue.

By measuring at various points around the journal's circumference, you can determine if the journal is worn out-of-round, and take measurements at each end of the journal, near the crank throw, to check for taper.