GMC Powertrain 4.3 L, Service Manual, Page: 92 / 196

6-82 Marine/Industrial 4.3L Engine
2000 Marine/Industrial
188015
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. Refer to Engine
Mechanical Specifications.
3. Install the connecting rod bearings into the connecting rod
cap and the connecting rod.
Notice: Refer to Fastener Notice in Cautions and Notices.
4. Install the connecting rod caps and the nuts.
Tighten
4.1. Tighten the connecting rod nuts on the first
pass, evenly to 27 N•m (20 lb ft).
4.2. Tighten the connecting rod nuts on the final
pass an additional 70 degrees using the J 36660.
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. Refer to Engine Mechanical 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.