Crankshaft Main Bearing: Description and Operation

DESCRIPTION








Bearing caps are not interchangeable and should be marked at removal to insure correct assembly (Fig. 98). Upper and lower bearing halves are NOT interchangeable. Lower main bearing halves of 1, 2, 4, 5 and 6 are interchangeable. Upper main bearing halves of 1, 2, 4, 5 and 6 are interchangeable. Upper and lower No. 3 bearing halves are flanged to carry the crankshaft thrust loads and are NOT interchangeable with any other bearing halves in the engine (Fig. 99). 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 undersizes: 0.025 mm (0.001 inch), 0.051 mm (0.002 inch), 0.076 mm (0.003 inch), 0.254 mm (0.010 inch), 0.305 mm (0.012 inch) and 0.508 mm (0.020 inch). Never install an undersize bearing that will reduce clearance below specifications.