11 25 530 Removing and installing/replacing all pistons (S63TU)

WARNING: This page does not describe the selected car, but rather 50 other vehicles, including the 2016 BMW M5, 2016 BMW ActiveHybrid 5, 2016 BMW 550i xDrive, 2016 BMW 550i, and 2016 BMW 535i xDrive. However, it is still accessible from the selected car via links, so may be relevant.

Special tools required:

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

IMPORTANT: If pistons and connecting rods are reused, they must be reinstalled in the same places.
Pistons and gudgeon pins 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.
Connecting rod bearings must always be replaced.

Necessary preliminary tasks:

Remove engine. See REMOVING/INSTALLING FRONT AXLE WITH ENGINE/TRANSMISSION (DUAL-CLUTCH TRANSMISSION)or REMOVING/INSTALLING FRONT AXLE WITH ENGINE/TRANSMISSION (MANUAL GEARBOX) .
Mount engine on ASSEMBLY STAND .
Remove both cylinder heads. See LEFT CYLINDER HEAD and RIGHT CYLINDER HEAD .
Remove oil sump. See LOWER OIL SUMP SECTION and UPPER OIL SUMP SECTION .
Remove OIL PUMP .

To release the connecting rod bolts (1), the crankshaft (2) must be moved to a suitable position.

Release connecting rod bolts (1).

Fig 1: Identifying Connecting Rod Bolts, Crankshaft, And Pairing Letters

Courtesy of BMW OF NORTH AMERICA, INC.

Screw the special tool 2 249 164 into the connecting rod.

Fig 2: Identifying Special Tool (2 249 164)

Courtesy of BMW OF NORTH AMERICA, INC.

NOTE: For installation and dismantling of the connecting rods, it is essential for the crankshaft to be exactly in alignment with the cylinder bore.

Position crankshaft at central bolt.

Press out the connecting rod and piston with the special tool 2 249 164 towards the cylinder head side.

Fig 3: Pressing Connecting Rod And Piston Using Special Tool (2 249 164)

Courtesy of BMW OF NORTH AMERICA, INC.

IMPORTANT: Pistons and gudgeon pins are paired and must not be fitted individually.

Lift out circlip and press out piston pin.

Fig 4: Lifting-Out Circlip

Courtesy of BMW OF NORTH AMERICA, INC.

If necessary, replace connecting rods.

NOTE: The connecting rod can also be replaced individually.

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

Fig 5: Identifying Gudgeon Pin

Courtesy of BMW OF NORTH AMERICA, INC.

Prior to installation, measure PISTON INSTALLATION CLEARANCE : Measure piston diameter with micrometer at measuring point A from lower edge of piston and offset at 90° to the axis of the gudgeon pin.

Measuring point A: see PISTONS WITH RINGS AND PINS - S63 ENGINE .

Fig 6: Measuring Piston Diameter Using Micrometer

Courtesy of BMW OF NORTH AMERICA, INC.

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

DIAMETER OF CYLINDER BORE .

TOTAL PERMISSIBLE WEAR CLEARANCE .

Fig 7: Adjusting Micrometer To Cylinder Bore Of Engine Block

Courtesy of BMW OF NORTH AMERICA, INC.

Installation note:

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

See Fig 8.

It must still be possible for the gudgeon pin to be moved easily.

Fig 8: Identifying Proper Installation Of Piston Circlip

Courtesy of BMW OF NORTH AMERICA, INC.

Insert the special tools 2 249 164 into the connecting rod.

INSTALLING CONNECTING ROD BEARING .

Fig 9: Inserting Special Tools (2 249 164) Into Connecting Rod

Courtesy of BMW OF NORTH AMERICA, INC.

Lightly coat pistons and piston rings with oil.

Offset the contact points of the piston rings by approx. 120° to each other but do not position above the gudgeon pin boss.

NOTE: Graphic S85.

Fig 10: Identifying 120° Offset Of Piston Ring Contact Points

Courtesy of BMW OF NORTH AMERICA, INC.

Keep piston rings compressed with special tool 11 7 280 .

Install piston so that arrow points to camshaft drive.

IMPORTANT: Risk of breakage of piston rings.

Press in piston only with finger force (do not knock in!).

Fig 11: Compressing Piston Rings Using Special Tool (11 7 280)

Courtesy of BMW OF NORTH AMERICA, INC.

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

Fig 12: Identifying Direction Arrow On Piston Crown

Courtesy of BMW OF NORTH AMERICA, INC.

Connect the crankshaft journal and connecting rod.

Remove the special tools 2 249 164 .

Fig 13: Pressing Connecting Rod And Piston Using Special Tool (2 249 164)

Courtesy of BMW OF NORTH AMERICA, INC.

NOTE: For purposes of clarity, the pairing letters (1) are shown on the removed connecting rod.

IMPORTANT: Connecting rods and connecting rod bearing caps are denoted with the same pairing letters (1), do not mix them up.
Fit bearing cap so that pairing letters match up.

Fig 14: Identifying Pairing Letters For Connecting Rod/Bearing Cap

Courtesy of BMW OF NORTH AMERICA, INC.

Apply light coat of oil to connecting rod bearing shells.

Fit the bearing cap so that the pairing letters (3) match up.

Install the connecting rod bolts (1).

Fig 15: Identifying Connecting Rod Bolts, Crankshaft, And Pairing Letters

Courtesy of BMW OF NORTH AMERICA, INC.

Secure connecting rod bolts (1) with special tool 00 9 120 .

Tightening torque 11 24 1 AZ .

Fig 16: Securing Connecting Rod Bolts Using Special Tool (00 9 120)

Courtesy of BMW OF NORTH AMERICA, INC.

Assemble engine.