11 25 671 Replacing piston rings of all pistons (N57 Diesel)

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Necessary preliminary work:

Remove PISTONS .

Remove all piston rings (2) with piston ring pliers (1).

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 Using Piston Ring Pliers

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Courtesy of BMW OF NORTH AMERICA, INC.

Installation note:

Install piston rings with "TOP" to piston crown.

Taper face compression ring
Stepped ring
Bevelled roof ring with spiral expander

Arrange piston ring contact points with offset of approx. 120° to one another, but not over gudgeon pin boss.

Fig 2: Identifying Compression Ring, Stepped Ring, And Bevelled Roof Ring

G09920754

Courtesy of BMW OF NORTH AMERICA, INC.

Installation note:

Marking (TOP) must point towards piston crown.

The oil scraper ring has no identification marking and can be installed in any position.

Fig 3: Identifying "TOP" Marking

G09920755

Courtesy of BMW OF NORTH AMERICA, INC.

Position piston rings offset 120° to each other.

Fig 4: Identifying 120° Offset Of Piston Rings

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Courtesy of BMW OF NORTH AMERICA, INC.

Measure side clearance.

Fig 5: Measuring Side Clearance

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Courtesy of BMW OF NORTH AMERICA, INC.

Measure end clearance.

Fig 6: Measuring End Clearance

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Courtesy of BMW OF NORTH AMERICA, INC.

Assemble engine.