11 25 671 Replacing Piston Rings On All Pistons (N62)

WARNING: This page is about a different variant/trim than selected.

(piston removed)

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

See 11 24 571 REPLACING ALL CONROD BEARINGS (N62/N62TU) .

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

Fig 1: Measuring Axial Clearance Of Piston Rings In Piston Ring Groove

Courtesy of BMW OF NORTH AMERICA, INC.

Remove piston rings (1 and 2) with 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.

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

Fig 2: Removing Piston Rings

Courtesy of BMW OF NORTH AMERICA, INC.

Measure end clearance. See 11 24 571 REPLACING ALL CONROD BEARINGS (N62/N62TU) .

Fig 3: Measuring End Clearance

Courtesy of BMW OF NORTH AMERICA, INC.

NOTE: Picture shows a schematic representation.

Installation:

Install piston rings with "TOP" to piston top.

Plain compression ring
Stepped compression ring "Top"
Steel band ring with support spring

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

Fig 4: Identifying Piston Rings With Top To Piston Top

Courtesy of BMW OF NORTH AMERICA, INC.

Installation:

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

Insert support spring (2) into piston ring groove.

CAUTION: Incorrect installation possible.
Contact points of support spring (2) slip very easily over each other when fitted.
Contact points must be positioned exactly on each other.
If the contact points overlap, the oil scraper ring will be damaged when the piston is installed.

Then fit steel band rings (1) so that contact joints are offset approx. 120°.

Fig 5: Identifying Oil Control Ring Comprises Steel Band Rings And Support Spring

Courtesy of BMW OF NORTH AMERICA, INC.