Crankshaft Main Bearing: Service and Repair

REPLACING MAIN CRANKSHAFT BEARING SHELL (M60)

(Engine dismantled)

Clean components before installing.

Preparations are described under heading "Replacing crankshaft" Service and Repair




Caution! Observe grinding stage of the crankshaft for proper bearing shells.




Note:
- Install main bearing shells (1) in the motor block with lubrication groove.
- Install main bearing shells (2) without lubrication groove in the main bearing caps.




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

Coat bearing shells with oil.

Install crankshaft.




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




Release hex head in main bearing cap.




Note:
(3) Install stop disk for collar bearing (in engine block).
(4) Install stop disk for collar bearing (in main bearing cap).




Caution! Check installed direction. Lubricant groove must be facing crankshaft.

Insert stop disks for collar bearing on both sides between crankshaft and engine block at main bearing 5.




Align thrust washers with contact face of main bearing caps.

Note:
- The main bearing caps (1...3) are marked with punched numbers.
- The main bearing caps 4 and 5 are not marked.




Note: Main bearing cap no.5 can be identified by the recesses for the stop disks of the thrust bearing.




Insert stop disks on both sides into grooves of main bearing cap no.5.




Lubricate crankshaft and main bearing shells.

Position main bearing caps (1...5) so that the retaining grooves of the main bearing shells are on one side.

Align main bearing cap flush with side of bearing seat.

Note:
- The main bearing cap screws must always be replaced by new ones.
- Do not wash off screw coating.
- No oil is permitted in the blind bores! (risk of cracking).




Tightening specifications for main bearing:
1. Tighten all screws on main bearing cover with jointing torque.
2. Unfasten screws on main bearing cover 5
3. Strike back and front of crankshaft with plastic hammer to center thrust bearing (do not damage crankshaft).
4. Tighten screws of main bearing cover 5 with jointing torque.
5. Tighten all screws of main bearing cover with special tool 11 2 110 or special tool 00 9 120 with torsion angle.

Tightening torque, Jointing torque = 20 Nm
Torque angle (M10) =70°
Torque angle (M11) =100°




Check axial play.

Check guide bearing shell, crankshaft and crankcase if necessary.




Tighten threaded protective bushes.

Tightening torque, 10 Nm




Tighten taper screw mount on main bearing (collar screws and spacer pins)

Note: Replace collar screws.

Tightening torque, Jointing torque = 20 Nm
Torque angle = 45°