11 21 531 Replacing all crankshaft main bearing shells (N47)

Special tools required: 

• 00 2 590

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.

Bearing classification from 1 to 3 possible.

1. Bearing color - yellow
2. Bearing color - green
3. Bearing color - white

Necessary preliminary tasks: 

• Remove CRANKSHAFT .
  Fig 1: Bearing Colors Combination

  Courtesy of BMW OF NORTH AMERICA, INC.

Bearing classification in bearing cap:

The number combination from left to right is from 1 to 5.

Possible combination of bearing colors.

1. 1 = yellow
2. 2 = green
3. 2 = green
4. 2 = green
5. 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.

Possible combination of bearing colors.

1. 2 = green
2. 1 = yellow
3. 2 = green
4. 1 = yellow
5. 2 = green

See Fig 2.

Fig 2: Bearing Colors Combination

Courtesy of BMW OF NORTH AMERICA, INC.

Place main bearing shell (1) with lubricating groove in crankcase (see arrows).

Observe combination of bearing colors according to the table.

Fig 3: Placing Main Bearing Shell With Lubricating Groove In Crankcase

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Installation note: 

Thrust bearing (1) on the crankshaft is installed at bearing position 3.

Fig 4: Thrust Bearing On Crankshaft

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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).

Fig 5: Placing Main Bearing Shell With Lubricating Groove In Bearing Cap

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Observe combination of bearing colors according to the table.

The bearing shells are marked with yellow, green or white color.

1. Bearing shell
2. Guide bearing

Observe grinding stage of main bearing journals  . See GROUND SIZES OF CONROD BEARING JOURNALS , GRINDING STAGES, CRANKSHAFT GUIDE BEARING and GROUND SIZES OF MAIN BEARING JOURNALS .

Fig 6: Bearing Shell And Guide

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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. Read off bearing clearance at width of crushed plastic thread (Plastigage) with aid of measuring scale.

If necessary, to correct bearing clearance, fit new bearing shells with a different color coding.

Fig 7: Checking Radial Clearance At Width Of Flattened Plastic Thread (Plastigage)

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CHECK SIDE CLEARANCE .

If necessary, check guide bearing shells, crankshaft and engine block.

Fig 8: Checking Crankshaft And Guide Bearing Shells

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Assemble engine.