11 25 530 Removing And Installing/Replacing All Pistons (N54)

WARNING: This page is about a different car, the 2010 BMW 135i, 2009 BMW 135i, and 2008 BMW 135i. However, it is still accessible from the selected car via links, so may be relevant.

Special tools required:

For the following special tools, refer to MAINTENANCE AND GENERAL INFORMATION - SPECIAL TOOLS .

00 9 120

For the following special tools, refer to ENGINE- SPECIAL TOOLS .

11 5 464
11 8 141
11 8 560
11 8 561
11 8 562
11 8 563
11 8 59

WARNING: Protective goggles must be worn when working on the piston pin circlip.

IMPORTANT: If pistons, connecting rods and bearing shells are reused, they must be reinstalled in the same places.
Individual connecting rod replacement is not permitted; they are classified according to weight categories.
Connecting rods and connecting rod bearing caps are marked with the same pairing letters; mixing them up will result in engine damage.
Piston and gudgeon pins are paired and must not be fitted individually.

Necessary preliminary tasks:

Remove engine . See 11 00 050 REMOVING AND INSTALLING ENGINE (N54) .
Mount engine on assembly stand . See 11 00 MOUNTING ENGINE ON ASSEMBLY STAND (N54) .
Remove intake air manifold . See 11 61 050 REMOVING AND INSTALLING INTAKE AIR MANIFOLD (N54) .
Remove cylinder head . See 11 12 100 REMOVING AND INSTALLING CYLINDER HEAD (N54) .
Remove oil sump .
Remove oil pump . See 11 41 000 REMOVING AND INSTALLING OIL PUMP (N54) .

NOTE: In event of heavy oil carbon residue:

Carefully remove oil carbon residue from cylinder wall.

NOTE: Illustrations show N46.

Fig 1: Locating Oil Carbon Residue On Cylinder Wall

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Do not release screw (1).

Oil spray nozzle (2) must not be maladjusted or bent. See 11 21 531 REPLACING ALL CRANKSHAFT MAIN BEARINGS (N54) .

If necessary, readjust (risk of damage) .

Fig 2: Identifying Screw And Oil Spray Nozzle

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Release connecting rod bolts (1).

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

Remove connecting rod bearing cap (2) in direction of arrow.

IMPORTANT: Connecting rods and connecting rod bearing caps are marked with the same pairing letters; mixing them up will result in engine damage.

Fig 3: Removing Connecting Rod Bearing Cap

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Screw special tool 11 8 590 into base of connecting rod.

Press out connecting rod and piston to cylinder head side.

IMPORTANT: Risk of damage to oil spray nozzle.

Fig 4: Screwing Special Tool 11 8 590

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Preliminary work:

Clamp special tool 11 8 561 in a vice.

Secure piston (1) with connecting rod to special tool 11 8 561.

Fig 5: Securing Piston Using Special Tool 11 8 561

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

WARNING: Protective goggles must be worn.

To lever out piston circlip (1), support special tool 11 5 464 on piston (2).

Lever out piston circlip (1) with special tool 11 5 464 in direction of arrow.

Fig 6: Removing Piston Circlip Using Special Tool 11 5 464

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Installation:

If necessary, replace connecting rods .

IMPORTANT: Connecting rods are divided into weight categories and are only available as a set.
Old and new connecting rods must not be installed in mixed combinations.

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 7: Installing Gudgeon Pin

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Measuring 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 8: Measuring Piston Diameter Using Micrometer At Measuring Point A

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Adjust micrometer to cylinder bore of engine block. Set internal caliper 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 .

Installation:

If necessary, replace piston .

Fig 9: Measuring Cylinder Bore Diameter

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WARNING: Protective goggles must be worn.

IMPORTANT: The opening of the piston pin circlip must be installed in the 6 o'clock position on the piston.
Risk of damage!

Insert piston circlip (2) into groove of special tool 11 8 562.

Bring piston circlip (2) into assembly position (1).

Fig 10: Inserting Piston Circlip Into Groove Of Special Tool 11 8 562

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WARNING: Protective goggles must be worn.

Slide special tool 11 8 563 up to piston pin circlip (2)

Special tools 11 8 562 and 11 8 563 are prepared.

Fig 11: Identifying Special Tools 11 8 562 And 11 8 563

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WARNING: Protective goggles must be worn.

Cutout on special tool 11 8 562 must point to piston crown; only then can special tool 11 8 563 be correctly fitted.

When special tools 11 8 562 and 11 8 563 are correctly positioned, the piston pin circlip must be driven in with a plastic hammer in the direction of the arrow.

NOTE: See Fig 12.

Fig 12: Drive In Piston Pin Circlip

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Piston pin circlip is correctly installed when opening (1) points downwards.

Fig 13: Position Of Installing Piston Pin Circlip

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NOTE: B 30.

Install all piston rings . See PISTON WITH RINGS AND PIN .

Install all bearing shells . See CONNECTING ROD WITH BEARING .

Coat piston and piston rings with oil.

Pre-install piston (2) in special tool 11 8 141.

Screw on special tool 11 8 590 in connecting rod (2).

Installation:

Check protective lugs (1) on special tool 11 8 590 for correct position and damage.

Fig 14: Identifying Special Tools 11 8 590 And 11 8 141

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Insert piston with connecting rod in cylinder.

IMPORTANT: Risk of damage to oil spray nozzle.
Danger of piston ring failure.
Press in piston in direction of arrow with finger pressure only, do not drive in.

Insert piston so that arrow on piston crown points to camshaft drive.

Press in piston (1) with special tool 11 8 141.

Fig 15: Direction Of Pressing Piston

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IMPORTANT: Connecting rod and connecting rod bearing cap are marked 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 16: Identifying Bearing Cap Marked With Pairing Letters