32. Crankshaft and Bearings Clean and Inspect

Crankshaft Bearing Inspection Procedure

Important: The following bearing wear conditions should be use to diagnose engine operating conditions or root cause of a condition. However, all connecting rod and main journal bearings that have been used in a running engine MUST be replaced. NEVER re-use the crankshaft or connecting rod bearings.





1. Inspect the main bearings for fatigue indicated by craters or pockets. Flattened sections on the bearing halves also indicate fatigue.





2. Inspect the main bearings for excessive scoring or discoloration on both front and back of the bearing halves.
3. Inspect the main bearings for dirt imbedded into the bearing material.





4. Inspect the main bearings for improper seating indicated by bright, polished sections.

Crankshaft Cleaning Procedure





- Clean the crankshaft journals with solvent and compressed air.
- Dry the crankshaft journals with compressed air and a soft, lint-free cloth.

Crankshaft Visual Inspection Procedure
- Install the crankshaft in a suitable fixture.
- Inspect each bearing journal and bearing for damage.
- Inspect the reluctor ring for any damage to the ring teeth.

Crankshaft Journal Diameter Measurement Procedure
1. Check the main and connecting rod journals for undersize using an outside micrometer.
2. Compare your measurements with those listed in the specifications. If the crankshaft journals are worn beyond the specified limits, the crankshaft must be replaced. Crankshaft machining is not allowed and there are no undersized bearings available for service.

Crankshaft Journal Out-of-Round Measurement Procedure





1. Using an outside micrometer, measure the journal at the extreme front and rear locations on the journal. Call these points A and B.
2. Measure the journal in two new locations exactly 90 degrees from the first points. Call these points C and D.
3. Subtract A from C and B from D. The differences will indicate journal out-of-round.
4. The out-of-round should not exceed 0.004 mm (0.00016 inch) maximum.
5. If the specifications are exceeded, replace the crankshaft.

Crankshaft Journal Taper Measurement Procedure





1. Using an outside micrometer, measure the journal at the extreme front (A) and rear (B) of the journal parallel to the crankshaft centerline.
2. Subtract the smallest from the largest measurement. The result will be the journal taper.
3. If the main bearing journal taper exceeds 0.004 mm (0.00016 inch), replace the crankshaft.
4. If the crankpin journal taper exceeds 0.005 mm (0.0002 inch), replace the crankshaft.
5. If the crankshaft journals are damaged or worn beyond dimensions, replace the crankshaft. No machining of the crankshaft journals is allowed.