11 21 531 Replace all crankshaft main bearing shells (M57T2-SCR)

Necessary preliminary work:

Remove ENGINE
Remove CYLINDER HEAD .
Remove THE GEAR CASE at front
Remove RADIAL SHAFT SEAL at rear
Remove OIL PUMP

IMPORTANT: Replace main bearing bolts.
Do not wash off bolt coating.

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

IMPORTANT: Check the grinding stage of the crankshaft.

Fig 1: Locating Grinding Stage Of Crankshaft

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Installation note:

When exchanging bearing shells (also exchange crankshafts), classification of bearing shell allocation in the crankcase is discontinued.

Only fit yellow bearing shells into the crankcase.

Fig 2: Identifying Bearing Shells

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NOTE: The axial guidance on the crankshaft is fitted to bearing position 6.

Insert the guide bearing shell in the engine block.

Fig 3: Identifying Guide Bearing Shell

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The crankshaft is marked with yellow, green or white paint, depending on the tolerance of the main bearing journal.

Fig 4: Locating Marks On Crankshaft

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Installation note:

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

Fig 5: Locating Mark On Bearing Shell

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

Bearing shell
Guide bearing

Observe grinding stage of main bearing journals.

Fig 6: Locating Bearing Shell Marks

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NOTE: Main bearing caps 1 to 5 are marked on exhaust side.
The main bearing caps 6 and 7 are not marked.
Main bearing cap 6 is a guide bearing.

Fig 7: Identifying Main Bearing Cap

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Check the main bearing clearance on the crankshaft.

Install crankshaft, fit special tool 00 2 590 (Plastigage type PG1) on the oil-free crankshaft.

Do not twist crankshaft.

Fig 8: Locating Main Bearing Clearance Of Crankshaft

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Install main bearing cap so that grooves in main bearing shell guide are on one side.

Align main bearing cap flush with side of bearing seat.

NOTE: To check main bearing clearance, use the old main bearing bolts.
Wash and oil main bearing bolts.

Fig 9: Locating Grooves On Main Bearing Shell Guide

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Tightening specifications for main bearing:

Tighten screws to jointing torque.
Tighten down bolts with special tool 00 9 120 to angle of rotation.
Tightening torque, see 11 11 1AZ in 11 11 ENGINE BLOCK

Fig 10: Tightening Main Bearing Bolts Using Special Tool (00 9 120)

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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 colour coding.

Fig 11: Locating Radial Clearance Reading On Width Of Flattened Plastic Thread

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Overview:

Colour code/shaft diameter/bearing strength

Ge = yellow
Gn = green
Ws = white

Crankshaft
Bearing clearance
Bearing shells: Yellow, green, white
Bearing cap

Fig 12: Identifying Bearing Clearance

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NOTE: Remove plastigage.
Coat main bearing shells and crankshaft with engine oil.

Install main bearing cap so that grooves in main bearing shell guide are on one side.

Align main bearing cap flush with side of bearing seat.

Fig 13: Locating Grooves On Main Bearing Shell Guide

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Tightening specifications for main bearing:

Tighten all screws on main bearing cap with jointing torque.
Loosen the screws on the main bearing cap 4.
Strike back and front of crankshaft with plastic hammer to center guide bearing (do not damage crankshaft).
Tighten bolts of main bearing cap no. 4 to jointing torque.
Tighten down all screws on main bearing caps with special tool 00 9 120 to angle of rotation.
Tightening torque, see 11 11 1AZ in 11 11 ENGINE BLOCK

Fig 14: Tightening Main Bearing Caps Screw Using Special Tool (00 9 120)

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Check side clearance.

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

Fig 15: Checking Side Clearance

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Assemble engine.