Crankshaft Main Bearing: Testing and Inspection
Checking bearing clearancesMain bearings
Measure clearances with (45) 30 06 558 Plastigage
Important: When measuring clearances with Plastigage, make sure that none of it gets into the oil holes.
1. Position the engine with the cylinder head surface downwards so that the weight of the crankshaft will not affect the measurements.
2. Clean the parts that are to be measured. Place a strip of Plastigage along the shaft.
3. Fit the bearing cap.
Tightening torque: 50 Nm (37 ft. lbs.) - 60˚ - 15˚
The crankshaft must not be rotated during measurement.
4. Remove the bearing cap. The strip of Plastigage should now have adhered to either the bearing cap or the main journal.
5. Measure the width of the Plastigage strip using the scale printed on the packaging and read off the clearance. One side of the packaging gives the measurement in millimetres, the other side in thousandths of an inch. Measure the strip at the widest point and take care not to touch it with your fingers.
Permissible main bearing clearance is 0.014 - 0.043 mm.
Big-end bearings
Measure clearances with (45) 30 06 558 Plastigage
Important: When measuring clearances with Plastigage, make sure that none of it gets into the oil holes.
1. Clean the parts that are to be measured. Place a strip of Plastigage along the shaft.
2. Fit the bearing cap.
Tightening torque: 35 Nm (26 ft. lbs.) - 45˚ - 15˚
The crankshaft must not be rotated during measurement.
3. Remove the bearing cap. The strip of Plastigage should now have adhered to either the bearing cap or the main journal.
4. Measure the width of the Plastigage strip using the scale printed on the packaging and read off the clearance. One side of the packaging gives the measurement in millimetres, the other side in thousandths of an inch. Measure the strip at the widest point and take care not to touch it with your fingers.
Permissible big-end bearing clearance: 0.013 - 0.061 mm.
