11 25 671 Replacing piston rings on all pistons (W10/W11)

WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 2008 MINI Cooper, 2007 MINI Cooper, 2006 MINI Cooper, 2005 MINI Cooper, and 2004 MINI Cooper. However, it is still accessible from the selected car via links, so may be relevant.

Necessary preliminary tasks:

Remove pistons.

Measuring axial clearance of piston rings in piston ring groove (1 and 2):

Fig 1: Measuring Axial Clearance Of Piston Rings

G03309759

Courtesy of BMW OF NORTH AMERICA, INC.

Refer to ENGINE - TECHNICAL DATA .

NOTE: It is not possible to measure the axial clearance of the oil scraper rings.

Remove piston rings (1 and 2) with piston ring compressing pliers.

Fig 2: Removing Piston Rings

G03309760

Courtesy of BMW OF NORTH AMERICA, INC.

NOTE: It might not be possible to find the identification on used piston rings.

Installation:

Put aside piston rings in correct sequence and installation position.

New pistons may only be installed together with new piston rings.

Measure end clearance.

Fig 3: Measuring End Clearance

G03309761

Courtesy of BMW OF NORTH AMERICA, INC.

Refer to ENGINE - TECHNICAL DATA .

Installation:

The taper face compression ring "top" is marked with an identification dot (1).

Fig 4: Identifying Taper Face Compression Ring Top

G03309762

Courtesy of BMW OF NORTH AMERICA, INC.

NOTE: Picture shows a schematic representation.

Installation:

Install piston rings with "identification dot" to piston crown.

Fig 5: Identifying Piston Rings

G03309763

Courtesy of BMW OF NORTH AMERICA, INC.

Plain compression ring
Taper face compression ring "identification dot"
Two-part oil scraper ring.

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

Installation:

Oil control ring comprises two steel band rings (1) and a support spring (2).

Fig 6: Identifying Oil Control Ring

G03309764

Courtesy of BMW OF NORTH AMERICA, INC.

Insert support spring (2) into piston ring groove and then fit steel band rings (1) so that contact points are offset by approx. 120°.