Crankshaft Main Bearing: Description and Operation

Main Bearing Identification:

The crankshaft is supported in five main bearings. All upper and lower bearing shells in the crankcase have oil grooves. The number three lower main thrust bearing is plain. Crankshaft end play is controlled by a flanged bearing on the number three main bearing journal.
Upper and lower Number 3 bearing halves are flanged to carry the crankshaft thrust loads and are NOT interchangeable with any other bearing halves in the engine. All bearing cap bolts removed during service procedures are to be cleaned and oiled before installation. Bearing shells are available in standard and the following undersized: 0.025 mm (0.001 inch) and 0.250 mm (0.010 inch). Never install an undersize bearing that will reduce clearance below specifications.





CRANKSHAFT SPECIFICATION CHART