11 25 530 Removing and installing/replacing all pistons (S65)

WARNING: This page is about a different car, the 2011 BMW M3, 2010 BMW M3, 2009 BMW M3, and 2008 BMW M3. However, it is still accessible from the selected car via links, so may be relevant.

WARNING: Safety goggles must be worn when working on the gudgeon pin circlip.

IMPORTANT: If pistons, connecting rods and bearing shells are reused, they must be reinstalled in the same places.
Piston and piston pin are matched to each other and can only be replaced as a pair.
Connecting rod and connecting rod bearing cap are cracked.
Identification is effected by means of identical pairing letters on the connecting rod big end.
Mixing up the components will result in engine damage.
Setting of special tool 11 5 343 must not be altered.

Necessary preliminary tasks:

Remove ENGINE .
Mount engine on assembly stand (S65) .
Remove INTAKE AIR MANIFOLD .
Remove cylinder head on left and right . See 1112105 REMOVING AND INSTALLING LEFT CYLINDER HEAD (S65) or 1112106 REMOVING AND INSTALLING RIGHT CYLINDER HEAD (S65) .
Remove ENGINE OIL SUMP .
Remove OIL PUMP .
Remove OIL SUCTION PUMP .

IMPORTANT: Do not bend oil nozzle (2) at outlets.

It is not possible to adjust the nozzles.

Oil nozzle (2) must be replaced if it is maladjusted or bent.

NOTE: Graphic shows crankshaft removed.

Fig 1: Identifying Oil Nozzle And Screws

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Release screws (1).

Remove holder for oil pipes.

Fig 2: Identifying Holder Screws

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Release connecting rod bolts (1) with special tool 12 2 100.

Remove connecting rod bearing cap with bearing shell.

Fig 3: Removing Connecting Rod Bolts

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Special tool 11 5 250 without locating rod must be screwed in on the connecting rod at the bottom.

Special tool 11 5 250 with locating rod must be screwed in on the connecting rod at the top.

Fig 4: Identifying Special Tool (11 5 250) On Connecting Rod

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Rotate crankshaft (1) in direction of arrow, risk of damage to special tool 11 5 250.

Remove piston with connecting rod and special tool 11 5 250.

Depiction of function on cylinders 1-4.

IMPORTANT: Risk of damage to oil nozzle.

Fig 5: Rotating Crankshaft

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Clamp special tool 11 5 341 in a vice.

NOTE: Piston and piston pin are optimized to each other.

There are two different inside diameters on the piston pin.

Screw matching special tool 11 5 342 into special tool 11 5 341.

Fig 6: Identifying Special Tool (11 5 342 And 11 5 341)

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Secure piston (1) with connecting rod to special tool 11 5 341.

Fig 7: Securing Piston With Connecting Rod To Special Tool (11 5 341)

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WARNING: Safety goggles must be worn for the next operation.

WARNING: Safety goggles must be worn.

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

Fig 8: Removing Piston Circlip With Special Tool (11 4 492)

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If necessary, replace connecting rods.

Installation:

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 9: Installing Gudgeon Pin

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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.

Piston diameter at measuring point A.

Fig 10: Measuring Piston Diameter

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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 cylinder bore.

Piston installation clearance.

Total permissible wear tolerance See ENGINE BLOCK, CYLINDER CRANKCASE S65 ; PISTONS WITH RINGS AND PINS S65 or PISTONS WITH RINGS AND PINS S65 .

If necessary, replace piston.

Fig 11: Measuring Cylinder Bore Diameter

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IMPORTANT: The connecting rods are not symmetrical.

Pay attention to elevation to direction of travel arrow.

Fig 12: Identifying Elevation To Direction Of Travel Arrow

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Make sure the connecting rod is in the correct installation position during preliminary installation.

On cylinders 6-10 the elevation (2) must point forwards with the arrow.

On cylinders 1-4 the elevation (1) must point rearwards against the arrow.

Valve pockets (E) point to inlet side.

Arrow direction is identical to direction of travel.

Fig 13: Identifying Valve Pockets And Cylinders Elevation

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On cylinders 5-8 the elevation must point forwards with the arrow.

On cylinders 1-4 the elevation (1) must point rearwards against the arrow.

IMPORTANT: No elevations on the connecting rod big end are permitted to point to each other during installation, risk of damage to connecting rod.

Fig 14: Identifying Cylinders Elevation

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Installation:

When installed, the two lugs on connecting rods (1 and 2) must point outwards.

Fig 15: Locating Lugs On Connecting Rods

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Secure piston (1) with connecting rod to special tool 11 5 341.

Fig 16: Securing Piston With Connecting Rod To Special Tool (11 5 341)

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WARNING: Safety goggles must be worn.

IMPORTANT: Setting of special tool 11 5 343 must not be altered.

Installation:

Insert piston circlip (2) so that opening points to window.

Insert piston circlip (2) into groove (1) of special tool 11 5 343.

Fig 17: Identifying Piston Circlip Groove

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NOTE: Graphic shows N52.

Position special tool 11 5 343 with window to recess on piston (see arrow).

Fig 18: Positioning Special Tool (11 5 343) With Window To Recess On Piston

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Position special tool 11 5 343 with window to recess on piston (see arrow).

Fig 19: Positioning Special Tool (11 5 343) With Window To Recess On Piston

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WARNING: Safety goggles must be worn.

Guide lug and aperture on special tool 11 5 343 must point to piston crown.

When special tools 11 5 343 and 11 5 344 are correctly positioned, the piston circlip must be driven in with a plastic hammer in the direction of the arrow.

NOTE: See graphic.

Fig 20: Installing Piston Circlip

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Installation:

Piston circlip (1) is correctly installed when the opening points upwards.

See graphic.

It must still be possible for piston pin to moved easily.

Fig 21: Installing Piston Circlip

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Install all PISTON RINGS .

Install all BEARING SHELLS .

Screw special tool 11 5 250 into connecting rod.

Always screw in special tool 11 5 250 with rod to exhaust side.

Preinstall piston with piston rings in special tool 11 9 500.

Fig 22: Inserting Special Tool (11 5 250) Into Connecting Rod

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Insert piston with connecting rod in cylinder.

IMPORTANT: Risk of damage to oil spray nozzle.
Danger of piston ring failure.

Insert piston so that arrow (direction of travel pointing forwards) on piston crown points to camshaft drive.

Piston cyl. 1-4 right side, cyl. 5-8 left side.

Press in piston with special tool 11 9 500.

Fig 23: Inserting Piston With Connecting Rod In Cylinder

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NOTE: Picture shows S85.

Arrow on piston crown must point to camshaft drive (direction of travel towards front).

Fig 24: Identifying Piston Crown Position

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IMPORTANT: Connecting rod and connecting rod bearing cap are identified with pairing letters (1) and must not be mixed up.
Mixing them up or incorrectly fitting the connecting rod bearing cap on the big end will result in engine damage.

Fig 25: Identifying Connecting Rod Bearing Cap Pairing Letters

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IMPORTANT: Risk of damage to oil nozzle.

Rotate crankshaft (1) in direction of arrow, risk of damage to special tool 11 5 250.

Insert piston with connecting rod and special tool 11 5 250.

Fig 26: Rotating Crankshaft

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Moisten connecting rod bearing shell and crankshaft journal slightly with engine oil.

Assemble connecting rod and crankshaft journal.

Remove special tool 11 5 250.

Fig 27: Identifying Special Tool (11 5 250) On Connecting Rod

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Install connecting rod bearing cap with bearing shell.

Secure connecting rod bolts (1) with special tools 12 2 100 and 00 9 120 TORQUE ANGLE MEASURING DIAL .

Tightening torque: 11 24 1AZ .

Fig 28: Securing Connecting Rod Bolts With Special Tools (12 2 100)

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Assemble engine.