11 25 671 Replacing piston rings on all pistons (N14)

WARNING: This page is about a different car, the 2008 MINI Cooper and 2007 MINI Cooper. However, it is still accessible from the selected car via links, so may be relevant.

Special tools required:

11 9 670

Necessary preliminary tasks:

Remove all Pistons .

Measuring axial clearance of piston rings in piston ring groove.

ENGINE - TECHNICAL DATA -- N14 ENGINE

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

Fig 1: Measuring Axial Clearance Of Piston Rings

Courtesy of BMW OF NORTH AMERICA, INC.

Remove compression ring and stepped ring upwards with piston ring pliers.

Oil scraper ring comprises two steel band rings and a support spring.

NOTE: Oil scraper ring cannot be removed with piston ring pliers.

Put aside piston rings in correct sequence and installation position.

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

Fig 2: Removing Compression Ring

Courtesy of BMW OF NORTH AMERICA, INC.

Installation:

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

Determine gap with a feeler gauge. See ENGINE - TECHNICAL DATA -- N14 ENGINE .

Fig 3: Measuring Piston Rings Gap

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Installation:

Piston rings with "TOP" identification must point to piston crown.

Fig 4: Piston Rings With "Top" Identification Mark

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Installation:

Piston rings with "TOP" identification must point to piston crown.

Plain compression ring
Taperface ring
Two-part oil scraper ring

Fig 5: Piston Rings Assembly And Components
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NOTE: Oil control ring comprises two steel band rings (1) and a support spring (2).

Installation:

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

120°.

Fig 6: Support Spring, Steel Band Rings And Assembly Directions

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Offset the contact points (1) of the piston rings by approx. 120° to each other but do not position above the piston pin boss.

Coat special tool 11 9 670 with sufficient engine oil. Risk of damage to piston rings!

NOTE: See Fig 7.

Fig 7: Piston Ring Contact Points

Courtesy of BMW OF NORTH AMERICA, INC.

Assemble engine.