Crankshaft installation is the first major step in engine reassembly, assuming the engine block and crankshaft have been cleaned, inspected, and repaired or reconditioned. Position the engine with the bottom facing up, then remove the main bearing cap bolts and lift out the caps, laying them out in the proper order for correct installation. If old bearing inserts are still in place, remove them from the block and caps, and wipe the main bearing surfaces with a clean, lint-free cloth to ensure cleanliness. Clean the back sides of the new main bearing inserts and place one half in each main bearing saddle in the block, with the corresponding half in the main bearing cap, ensuring proper alignment of tabs and oil holes. The flanged thrust bearing must be installed in the third cap and saddle. Clean the bearing faces in the block and crankshaft main bearing journals, checking the oil holes in the crankshaft for dirt. Once the crankshaft is confirmed clean, carefully lay it in position in the main bearings. Before permanent installation, check the main bearing oil clearance using appropriately sized pieces of Plastigage placed on each crankshaft main bearing journal. Clean the bearing faces in the caps and install them in their respective positions with arrows pointing toward the front of the engine, tightening the main bearing cap bolts in three steps to the specified torque without rotating the crankshaft. After removing the bolts and lifting off the main bearing caps, compare the width of the crushed Plastigage to the scale on the container to determine the main bearing oil clearance, ensuring it meets specifications. If the clearance is incorrect, verify that no dirt or oil was present during measurement, and if necessary, consider different bearing inserts. Carefully scrape off any Plastigage material from the main bearing journals and bearing faces, then lift the crankshaft out, clean the bearing faces in the block, and apply a thin layer of clean moly-base grease or engine assembly lube to each bearing surface, including the thrust faces. After ensuring the crankshaft journals are clean, lay the crankshaft back in place, clean the bearing faces in the caps, apply lubricant, and install the caps with arrows pointing toward the front, followed by the bolts. Tighten all except the third cap bolts to the specified torque, then tighten the third cap bolts to 10-to-12 ft-lbs, tapping the ends of the crankshaft to align the thrust surfaces before retightening all main bearing cap bolts. For manual transmission models, install a new pilot bearing in the end of the crankshaft, then rotate the crankshaft by hand to check for binding. Finally, check the crankshaft end play with a feeler gauge or dial indicator, ensuring it is correct if the thrust faces are not worn or damaged and new bearings are installed, followed by the installation of the rear main oil seal.
