11 25 530 Removing and installing/replacing all pistons (M57T2)

Necessary preliminary tasks:

Remove ENGINE .
Remove cylinder head.
Remove OIL PAN
Remove OIL PUMP .

IMPORTANT: Re-install piston, connecting rod and bearing shells back in the same position and in the same installation location.
Connecting rods and bearing covers are designated with the same pair number: do not mix them.
Replace connecting rod bolts.

Unscrew conrod bearing cover.

Pull out connecting rod and piston to the cylinder head end.

IMPORTANT: Position crankshaft vertically.
Proceed with care at the cylinder wall and oil spray nozzles Risk of damage.

Fig 1: Locating Connecting Rod Bearing Cap

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Preliminary work:

Clamp special tool 11 6 111 in a vice.

Secure piston (1) with connecting rod to special tool 11 6 111.

Fig 2: Securing Special Tool (11 6 111) On Vice

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WARNING: Protective goggles must be worn for the next work step.

WARNING: Protective goggles must be worn.

Lever out piston circlip with special tool 11 4 492 in direction of arrow.

IMPORTANT: Piston and gudgeon pin are matched to each other.
They must not be mixed up.

Fig 3: Removing Piston Circlip Using Special Tool (11 4 492)

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Before installation, measure piston installation clearance. Measure piston diameter with micrometer at measuring point A from bottom edge of piston and offset at 90° to the axis of the gudgeon pin. Distance A, refer to TECHNICAL DATA

Fig 4: Measuring Piston Diameter Using Micrometre

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Adjust micrometer to cylinder bore of engine block. Set internal calliper on micrometer to zero. Measure bottom, center and top of cylinder bore in direction of travel and direction of engine rotation.

Diameter of the cylinder bore, refer to TECHNICAL DATA

Piston installation clearance, Refer to TECHNICAL DATA

Permitted total wear clearance, refer to TECHNICAL DATA .

Fig 5: Measuring Diameter Of Cylinder Bore

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If necessary, replace connecting rods.

The BMW Parts Service only supplies connecting rods in complete sets.

NOTE: The gudgeon pin must be able to be pressed through the liner by hand with little force and must not display any significant play.

Fig 6: Pressing Gudgeon Pin

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Replace CONROD BEARING SHELLS .

Fit conrod to piston in such a way that both of the visible pair numbers on the installation direction arrow on the piston point to the right.

Fig 7: Locating Piston Installing Matching Numbers

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WARNING: Protective goggles must be worn.

Insert piston circlip (2) into groove (1) of special tool 11 6 112.

Bring piston circlip into assembly position.

Fig 8: Inserting Piston Circlip Into Groove Of Special Tool (11 6 112)

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WARNING: Protective goggles must be worn.

Guide lug and cutout on special tool 11 6 112 must point to the piston crown; only then can special tool 11 6 113 be correctly fitted.

When special tools 11 6 112 and 11 6 113 are correctly positioned, the piston pin circlip must be driven in with a plastic hammer in the direction of the arrow.

NOTE: See illustration.

Fig 9: Inserting Piston Pin Circlip

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Insert special tool 11 6 330 in conrod.

Lightly coat pistons and piston rings with oil.

Align contact points on piston rings (offset at approx. 120°, but do not arrange over piston pin lug).

Fig 10: Inserting Special Tool (11 6 330) On Connecting Rod

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Press together piston rings with special tool 11 8 140.

Install piston so that arrow points to camshaft drive.

IMPORTANT: Danger of piston ring failure.

Only press pistons into place with finger force - do not knock in!

Fig 11: Pressing Piston Rings Using Special Tool (11 8 140)

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Attach crankpin to connecting rod.

Remove special tool 11 6 330.

Fig 12: Identifying Special Tool (11 6 330)

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Apply light coat of oil to connecting-rod bearing shells.

Fit bearing caps so that pair numbers match up.

Installation:

Use new conrod bolts.

Fig 13: Locating Bearing Caps Matching Numbers

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Tighten down connecting rod bolts with special tool 00 9 120.

Installation

Tightening torque, see 11 24 1AZ in CONNECTING RODS AND BEARINGS .

Fig 14: Tightening Connecting Rod Bolt Using Special Tool (00 9 120)

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The gasket thickness must be recalculated when work is carried out on the crankshaft drive or pistons.

Measuring the piston clearance:

Fit dial gauge with measuring fixture special tool 00 2 530 on cleaned engine block sealing surface and set under pretension to zero.

Fig 15: Measuring Piston Clearance

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Position piston at TDC.

Clean piston at measuring points (1 and 2).

Fit dial gauge at measuring point (1) on piston and determine highest point by rotating crankshaft.

Measure and note down piston clearance at measuring points (1 and 2) on all pistons.

Fig 16: Measuring Highest Piston Clearance

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The highest piston clearance at the measuring points (1 and 2) of all the pistons determines the thickness of the cylinder head gasket.

Piston clearance 0.92... 1.03 mm

Install 2-hole cylinder head gasket.

Piston clearance over 1.03 mm

Install 3-hole cylinder head gasket.

Thickness of cylinder head gasket (1).

Fig 17: Identifying Cylinder Head Gasket

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Assemble engine.

Check engine operation and check for leaks.