11 21 531 Replacing all crankshaft main bearing shells (N47 D20 O1)
Special tools required:
There must be no oil in the blind holes (risk of cracking) .
Do not wash off bolt coating.
Incorrect installation of the bearing cap leads to damage to the crankcase.
Check grinding stage of crankshaft . See CRANKSHAFT AND BEARINGS (N47) .
The code letter K on the crankcase and on the crankshaft stands for "Kupplungsseite" (German = clutch end).
Installation note:
The assignment of the bearing shells in the crankcase (classification) may no longer apply after the crankshaft has been replaced.
Install yellow bearing shells in crankcase (see BMW Parts installation instructions).
Bearing classification from 1 to 3 possible.
- Bearing color - yellow
- Bearing color - green
- Bearing color - white
Necessary preliminary tasks:
- Remove CRANKSHAFT .
Bearing classification in bearing cap:
The number combination from left to right is from 1 to 5.
Example: Possible combination of bearing colors.
- 1 = yellow
- 2 = green
- 2 = green
- 2 = green
- 3 = white
See Fig 1.
Bearing classification in crankcase:
The code letter K on the crankcase stands for "Kupplungsseite" (German = clutch end).
The number combination from left to right is from bearing seat 5 to 1.
Example: Possible combination of bearing colors.
- 2 = green
- 1 = yellow
- 2 = green
- 1 = yellow
- 2 = green
The classifications 1 (yellow) and 3 (white) and 3 (white) and 1 (yellow) are not allowed.
The classification 2 (green) and 2 (green) should be selected.
See Fig 2.
| (1/1) Bearing cap/yellow | (2/1) Bearing cap/yellow | (3/1) Bearing cap/green |
| (1/1) Crankcase/yellow | (2/1) Crankcase/green | (3/1) Crankcase/green |
| (1/2) Bearing cap/green | (2/2) Bearing cap/green | (3/2) Bearing cap/green |
| (1/2) Crankcase/yellow | (2/2) Crankcase/green | (3/2) Crankcase/white |
| (1/3) Bearing cap/green | (2/3) Bearing cap/white | (3/3) Bearing cap/white |
| (1/3) Crankcase/green | (2/3) Crankcase/green | (3/3) Crankcase/white |
Place main bearing shell (1) with lubricating groove in crankcase (see arrows).
Observe combination of bearing colors according to the table.
Installation note:
Thrust bearing (1) on the crankshaft is installed at bearing position 3.
Observe combination of bearing colors according to the table.
Place main bearing shell (1) with no lubricating groove in the bearing cap (see arrows).
Installation note:
Pay attention to guide lug on main bearing shell (1).
Observe combination of bearing colors according to the table.
The bearing shells are marked with yellow, green or white color.
- Bearing shell
- Guide bearing
Observe grinding stage of main bearing journals . See CRANKSHAFT AND BEARINGS (N47) .
Position special tool 00 2 590 on main bearing to be measured and bolt to main bearing cap.
Tightening torque: 11 11 1AZ .
Remove main bearing cap and read off radial clearance at width of flattened plastic thread (Plastigage) with assistance of measuring scale.
If necessary, to correct bearing clearance, fit new bearing shells with a different color coding.
check side clearance. See CRANKSHAFT AND BEARINGS (N47) .
If necessary, check guide bearing shells, crankshaft and engine block.
Assemble engine.