Micrometer Method For Connecting Rod Bearings

Notice: Do not shim, scrape, or file bearing inserts. Do not touch the bearing surface of the insert with bare fingers. Skin oil and acids will etch the bearing surface.





1. Measure the crankpin diameter with a micrometer in several places, approximately 90 degrees apart, and then average the measurements.
2. Determine the taper and the out-of-round.
3. Install the connecting rod bearings into the connecting rod cap and the connecting rod.
4. Install the connecting rod caps and the nuts.
Tighten the connecting rod nuts in the first pass, evenly to 27 Nm (20 ft. lbs.).
Tighten the connecting rod nuts in the final pass an additional 70 degrees using the J36660-A.
5. Measure the connecting rod bearing Inside Diameter (ID) at the top and the bottom using an inside micrometer.
6. Compare the connecting rod bearing clearance to the specifications.
7. If the connecting rod bearing clearance is within specifications, the connecting rod bearing is satisfactory.
^ Replace the connecting rod bearing if the clearance is not within specifications.
^ Always replace both the upper and the lower connecting rod bearings as an assembly.

8. A standard or undersize connecting rod bearing combination may result in the proper clearance.

If the proper connecting rod bearing clearance cannot be achieved using the standard or the undersize connecting rod bearings, it will be necessary to replace or repair the crankshaft.