Chevrolet 12685656 Crankshaft Assembly

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Before removing the crankshaft, measure the endplay by mounting a dial indicator and touching the end of the crankshaft. Pry the crankshaft to the rear and zero the dial indicator, then pry it to the front and check the reading. If the endplay is greater than 0.003 to 0.010 inches, check for wear on the crankshaft thrust surfaces. To remove the crankshaft, loosen the main bearing cap bolts and remove the caps. Lift the crankshaft out of the engine, being careful due to its weight. When installing the crankshaft, position the engine block with the bottom facing up and remove the main bearing caps. Clean the bearing surfaces and install new bearing inserts. Check the main bearing oil clearance using Plastigage. Apply clean engine oil to all bolt threads and tighten the bolts to the specified torque. Remove the bolts and lift off the main bearing caps, then compare the width of the crushed Plastigage to determine the main bearing oil clearance. Scrape off any Plastigage residue and lift the crankshaft out of the cylinder block. Apply lubricant to the bearing surfaces and lay the crankshaft back in place. Apply lubricant to the bearing insert faces and clean the engine block and bearing cap mating surfaces. Apply clean engine oil to all bolt threads and tighten the main bearing cap bolts to the specified torque. Recheck the crankshaft endplay and rotate the crankshaft by hand to check for any binding.