Replacing Main Bearing Shells

REPLACING MAIN-BEARING SHELLS

- M50TU VANOS -









Crankshafts are marked with yellow, green or white paint depending on main-bearing tolerances.






Note:
Thrust-bearing shells are installed at bearing No.6.






Note:
1. Bearing shells with continuous lubricating groove and one retaining lug (for crankcase).
2. Bearing shells without continuous lubricating groove and with two retaining lugs (for bearing caps)






Installation:
When replacing bearing shells (also for exchange crankshafts), classification does not apply for allocation of bearing shells in crankcase.
Only install yellow bearing shells in crankcase. Check grinding size of crankshaft!






Installation:
Bearing-shell classification for bearing caps is marked on crankshaft with yellow, green or white paint.






Caution!
Check grinding size of crankshaft.

1 coat of paint: Size 1(0.25 mm)
2 coats of paint: Size 2 (0.50 mm)






Checking axial clearance:
If permissible clearance is exceeded.
Check crankshaft and thrust bearing shells and replace if necessary.






Check bearing clearance:
Only carry out this step for control purposes.
Install crankshaft. Place Type PG 1 Plastigage (Special Tool 00 2 590) on crankshaft wiped clean of oil and tighten bearing cap bolts as specified.

Do not turn crankshaft.






Remove bearing cap and read bearing clearance by measuring width of the flattened Plastigage with help of the supplied scale.

Install new bearing shells or bearing shells with a different colour code to correct the bearing play.






Survey of:
Colour code/shaft diameter/bearing-shell thickness

Triple-classification colour codes:

Ge = Yellow
Gn = Green
Ws = White
1. Crankshaft diameter
2. Bearing play
3. Bearing-shell thickness
4. Mounting-block diameter