Crankshaft Main Bearing: Testing and Inspection

INSPECTION

CRANKSHAFT AND CRANKSHAFT BEARING
1. Clean the crankshaft completely and check for cracks by means of liquid penetrant tester etc., and replace if defective.
2. Measure the crankshaft bend, and correct or re place if it exceeds the limit.

NOTE:
If a suitable V-block is not available, install the #1 and #5 crankshaft bearing on cylinder block, position the crankshaft on these bearings and measure the crankshaft bend using a dial gauge.





3. Inspect the crank journal and crank pin for wear.
If they are not within the specifications, replace the bearing with a suitable (undersize) one, and then replace or recondition the crankshaft as necessary. When grinding the crank journal or crank pin, finish them to specified dimensions according to the undersize bearing to be used.

Crank pin:
Out-of-roundness
0.003 mm (0.0001 inch)
Cylindricality
0.004 mm (0.0002 inch)
Grinding limit
To 51.750 mm (2.0374 inch) dia.








O.D.: Outer Diameter
4. Measure the thrust clearance of crankshaft at center bearing. If the clearance exceeds the limit, replace the bearing.





5. Inspect individual crankshaft bearings for signs of flaking, seizure, melting, and wear.
6. Measure the oil clearance on each crankshaft bearing by means of plastigauge. If the measurement is not within the specification, replace the defective bearing with an undersize one, and replace or recondition the crankshaft as necessary.

Crankshaft oil clearance:
Standard
0.010 - 0.030 mm (0.0004 - 0.0012 inch)
Limit
0.040 mm (0.0016 inch)