Connecting Rod Bearing: Service and Repair

Two types of rod bearings are available, standard and a .0098 inch undersize bearing. To distinguish them, the undersize bearing has the stamped number US025 on its back and the standard size bearing has no markings. Check rod bearing clearance as follows:
1. Clean bearings and crankshaft pin using a suitable solvent.
2. Place a piece of gaging plastic the full width of the crankpin as contacted by bearing (parallel to crankshaft), avoiding oil passage hole.

Fig. 48 Measuring Rod Bearing Clearance:

3. Install rod bearing cap and tighten cap bolts to specifications. Ensure arrow mark on cap is pointed toward crankshaft pulley. Do not rotate crankshaft while gaging plastic is installed.
4. Remove rod bearing cap. Using scale on gaging plastic envelope, measure gaging plastic width at its widest point, Fig. 48.
5. If clearance exceeds .0031 inch, use a new standard size bearing and remeasure clearance.
6. If clearance can not be brought within specifications using new standard size bearing, regrind crankpin to undersize and use .0098 inch undersize bearing.