11 21 531 Replacing all crankshaft main bearing shells (S54): Installation:

When the bearing shells or the crankshaft are replaced, the classification for bearing shell arrangement in the engine block is eliminated.

Only install yellow bearing shells in the engine block.

Insert pilot bearing shell in the engine block.

Fig 1: Inserting Pilot Bearing Shell

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Insert crankshaft in engine block.

Fig 2: View Of Crankshaft

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The bearing shell classification for the bearing cover is marked on the crankshaft in yellow, green or white paint.

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

Fig 1: View Of Main Bearing Shell

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

1. Bearing shell
2. Guide bearing

Fig 2: Identifying Guide Bearing And Bearing Shell

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Observe grinding stage of main bearing journals. Refer to CRANKSHAFT AND BEARINGS .

Fig 3: Identifying Main Bearing Caps Mark

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Main bearing caps 6 and 7 are not marked.

Main bearing cap 6 is thrust bearing.

Check clearance on main crankshaft bearing.

Fig 4: Checking Clearance On Main Crankshaft Bearing

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Install crankshaft and place special tool 00 2 590 (Plastigage Type PG1) on oil-free crankshaft.

Do not twist crankshaft.

Insert main bearing caps in such a way that guide grooves of main bearing shells lie on one side.

Align main bearing cap flush with side of bearing seat.

Fig 5: Aligning Main Bearing Cap

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Installation: 

To check main bearing clearance, use the old main bearing screws.

There must be no oil in the blind holes (risk of cracking).

1. Tighten down main bearing screws with jointing torque.
2. Tighten down main bearing screws using special tool 00 9 120 and torsion angle.

Tightening torque, 11 11 1AZ. Refer to 11 11 ENGINE BLOCK .

Fig 6: Tightening Down Main Bearing Screws

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Remove main bearing cap and read off bearing clearance at width of pinched plastic thread on measuring scale.

Crankshaft bearing clearance radial, refer to CRANKSHAFT AND BEARINGS .

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

Fig 7: Checking Crankshaft Bearing Clearance

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Coat main bearing shells and crankshaft with engine oil.

Insert main bearing cap in such a way that grooves of main bearing shell guide lie on one side.

Align main bearing cap flush with side of bearing seat.

Fig 8: Aligning Main Bearing Cap

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Always replace screws of main bearing caps with new ones.

There must be no oil in the blind holes (risk of cracking).

Holders for oil lines are fitted on main bearing caps 3 and 5.

Holder (1) with elongated hole in vertical direction.

Holder (2) with elongated hole in horizontal direction.

Fig 1: Identifying Holders

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Tightening specifications for main bearing:

1. Tighten all screws on main bearing cover with jointing torque.
   Fig 2: Tightening Screws On Main Bearing Cover

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2. Unfasten screws on main bearing cover 6.
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 6 with jointing torque.
5. Tighten down all screws on main bearing caps with special tool 00 9 120 and torsion angle.

Tightening torque, 11 11 1AZ. Refer to 11 11 ENGINE BLOCK .

Check axial play.

Fig 3: Checking Axial Play

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If permitted end float is exceeded, check crankshaft, guide bearing shells and engine block, replacing if necessary.

End float. refer to CRANKSHAFT AND BEARINGS .