Crankshaft Main Bearing: Service and Repair

(engine dismantled)

Note: Clean components before installing.





Caution: Note grinding stage of crankshaft, refer to Engine, Specifications





Note:
Injection nozzles for cooling the pistons are installed on the underside of the cylinder between the bearing seats.
In order to avoid the possibility of injury from the piston or connecting rod, the location of spray nozzles is equipped with special tool 11 7 320.





Check the setting of the spray nozzles.
Attach special tool 11 7 320 to the intake side in the receiving bore hole in the engine block.
The spray nozzles must fit into the guide of special tool 11 7 320.
If necessary, loosen the spray nozzles and adjust and tighten them using special tool 11 7 320.
Tightening torque, refer to Engine, Specifications.





Note: When crankshaft or main bearing shells are being replaced, the classification for the arrangement of the main bearing shells in the crankcase is no longer of significance. Install yellow main bearing shells in crankcase.





Note: Guide bearing shell installed at bearing No. 4 is sole means of axial alignment for crankshaft.
Install guide bearing shell in crankcase.





Install crankshaft.

Note: The crankshaft is marked with yellow, green or white paint according to the tolerance of the main journal.





Note: Place main bearing shells with same color code as that of crankshaft in main bearing caps.





Note: Main bearing caps 1 through 3 bear identification markings on exhaust side.
The main bearing caps 4 and 5 are not marked.
Note that main bearing cap 4 has shoulders machined into end faces.





Check main bearing clearance:
Fit special tool 00 2 590 (Plastigage Type PG 1) to the oil-free crankshaft.
Do not twist crankshaft.





Place main bearing caps in position with grooves of all caps on same side. Align main bearing cap flush with side of bearing seat.

Note: To check main bearing clearance, use old main bearing screws.

No oil is permitted in the blind bores (danger of cracking).
Wash and oil screws.





1. Tighten the main bearing bolts to joining torque.
2. Tighten down screws with special tool 11 2 110 or with special tool 00 9 120 with torsion angle.
Tightening torque, refer to Engine, Specifications.





Remove main bearing cover and read off bearing clearance on width of squashed plastic thread using the measuring scale.
Main bearing clearance, refer to Engine, Specifications
Install new bearing shells with different color codes if necessary in order to check bearing clearance.





Summary:
Color code/shaft diameter/bearing strength
Ge = yellow
Gn = green
Ws = white
1. Crankshaft
2. Bearing clearance
3. Bearing shells: yellow, green or white
4. Bearing cover





Installation: Remove plastic thread. Coat main bearing shells and crankshaft with engine oil. Place main bearing caps in position with grooves of all caps on same side. Align main bearing cap flush with side of bearing seat. Always replace main bearing screws with new ones. No oil is permitted in the blind bores (danger of cracking). Wash and oil screws.





1. Tighten the main bearing bolts to joining torque.
2. Tighten down screws with special tool 11 2 110 or with special tool 00 9 120 with torsion angle.
Tightening torque, refer to Engine, Specifications.





Check end float.
End float, refer to Engine, Specifications
If necessary, check the guide bearing shell, crankshaft and engine block.