11 25 530 Removing And Installing/Replacing All Pistons (N62): Installation

WARNING: This page is about a different car, the 2005 BMW 645Ci and 2004 BMW 645Ci. However, it is still accessible from the selected car via links, so may be relevant.

Installation of pistons is described separately from removal. The assembly sequence for removal and installation is different.

If necessary, replace connecting rods.

NOTE: The Conrods can also be replaced individually.

The piston pin must be able to be pressed through the liner by hand with little force and must not display any significant play.

Fig 1: Identifying Piston Pin

Courtesy of BMW OF NORTH AMERICA, INC.

Prior to installation, measure piston installation clearance:

Measure piston diameter with micrometer at measuring point A from lower edge of piston and offset by 90° to piston pin axis.

Measuring point A. Refer to ENGINE - TECHNICAL DATA - 645CI .

Fig 2: Measuring Piston Installation Clearance

Courtesy of BMW OF NORTH AMERICA, INC.

Adjust micrometer to cylinder bore of engine block. Set internal caliper on micrometer to zero. Measure bottom, center and top of cylinder bore in direction of travel and direction of engine rotation.

Diameter of cylinder bore.

Piston installation clearance. Refer to ENGINE - TECHNICAL DATA - 645CI .

Total permissible wear tolerance. Refer to ENGINE - TECHNICAL DATA - 645CI .

Fig 3: Measuring Cylinder Bore

Courtesy of BMW OF NORTH AMERICA, INC.

NOTE: The pistons and conrods of cylinders 1 to 8 are identical.

CAUTION: The conrods of cylinder banks 1 to 4 and 5 to 8 are mounted to the pistons differently.