11 25 671 Replacing Piston Rings On All Pistons (S85)

WARNING: This page does not describe the selected car, but rather 10 other vehicles, including the 2010 BMW M6, 2010 BMW M5, 2009 BMW M6, 2009 BMW M5, and 2008 BMW M6. However, it is still accessible from the selected car via links, so may be relevant.

Necessary preliminary tasks:

Remove engine .
Remove all pistons .

Remove piston rings with a piston-ring compressing pliers.

NOTE: It might not be possible to find the identification on used piston rings.
Put aside piston rings in correct sequence and installation position.

Fig 1: Removing Piston Rings With Piston-Ring Compressing Pliers

G04748257

Courtesy of BMW OF NORTH AMERICA, INC.

Installation:

Piston rings marked with "R" must point to piston crown.

Groove (2), plain compression ring.

Groove (3), stepped ring.

Groove (4), bevel-edged oil control ring.

Fig 2: Identifying Plain Compression Ring, Stepped Ring And Bevel-Edged Oil Control Ring Groove

G04741635

Courtesy of BMW OF NORTH AMERICA, INC.

Piston ring (1), bevel-edged oil control ring.

Piston ring (2), stepped ring.

Piston ring (3), plain compression ring.

Fig 3: Identifying Plain Compression, Stepped And Bevel-Edged Oil Control Piston Ring

G04741636

Courtesy of BMW OF NORTH AMERICA, INC.

Installation:

Piston rings marked with "R" must point to piston crown.

Plain compression ring is marked with (R).

Stepped ring is marked with (R1).

Fig 4: Identifying Mark On Plain Compression Ring

G04741637

Courtesy of BMW OF NORTH AMERICA, INC.

Measure axial play.

Fig 5: Measuring Axial Play

G04739784

Courtesy of BMW OF NORTH AMERICA, INC.

Measure end clearance.

Fig 6: Measuring Ring End Clearance

G04739786

Courtesy of BMW OF NORTH AMERICA, INC.

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

Fig 7: Identifying Piston Ring Contact Point Offset Position

G04741640

Courtesy of BMW OF NORTH AMERICA, INC.

Assemble engine.