Before repairing the bearing, the car should first check whether the bearing housing hole meets the requirements
Bearing inspection and repair
1) Inspection and correction of the bearing housing hole The damage of the crank bearing in use is mainly wear, fatigue peeling and melting. When the engine is overhauled, new bearings must be replaced. Before repairing the bearing, first check whether the bearing housing hole meets the requirements. The roundness and cylindricity error of the bearing housing hole is not more than 0.015mm. The method of inspection and correction is: clean the bearing seat, install the bearing cap, and tighten the fixing bolt or nut according to the specified torque. When the roundness and cylindricity of the seat hole are exceeded, the welding can be welded on both ends of the bearing cap. Machining or padding adjustment, it is not allowed to repair the bearing cap.
Clean the oil of the journal and bearing, cut the gap of the plastic wire into the same length as the bearing width, and place it on the crank pin so that it is parallel to the center line of the shaft. Carefully install the bearing cap and set the nut according to the regulations. Torque tightening, carefully remove the bearing cap, use the measuring tape printed on the plastic line gap gauge bag, measure the width of the widest part of the flattened plastic wire, and obtain the gap value. Replace the new bearing when the limit value is exceeded.
2) Matching of bearings At present, the commonly used bearing alloys for gasoline engine crankshaft bearings are babbitt and high-tin aluminum alloy. The thickness of the alloy layer is 0.30~0.35mm. In addition to the standard size, the bearing size is reduced by 0.25mm according to the inner diameter. The primary repair size corresponds to the crankshaft journal for use in repairs.