LEMON Manuals: Even more car manuals for everyone
Home >> BMW >> 2000 >> M Coupe >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Engine - Repair >> Piston with rings and pin >> 11 25 530 Removing and installing or replacing all pistons (M52 / S52 / M52TU / M54 / M56)

11 25 530 Removing and installing or replacing all pistons (M52 / S52 / M52TU / M54 / M56)

Special tools required: 

NOTE: For special tools, refer to ENGINE - SPECIAL TOOLS .
  1. (engine removed)
  2. Remove cylinder head. See 11 12 100 Removing and installing/replacing cylinder head (M52TU / M54 / M56) 

Removal: 

Removal of pistons is described separately from installation. Assembly sequence for removal and installation is different.

IMPORTANT: Re-install piston, connecting rod and bearing shells back in the same position and in the same installation location. Connecting rods and bearing covers are designated with the same pair number: do not mix them.

Remove oil pump.

If oil pump and oil scraper are two parts: Remove oil scraper.

Fig 1: Removing Oil Pump
G03164011Courtesy of BMW OF NORTH AMERICA, INC.
NOTE: Figure shows crankshaft removed.

On engines with spray nozzles for piston cooling on cylinder underside:

Fig 2: Identifying Spray Nozzles For Piston Cooling
G03164012Courtesy of BMW OF NORTH AMERICA, INC.
IMPORTANT: When removing and installing pistons, make sure the piston cooling spray nozzles are not damaged.

Installation: 

Screw threads are coated with screw securing adhesive (Loctite). Replace screws.

In event of heavy oil carbon residue:

Carefully remove oil carbon residue from cylinder wall.

Fig 3: Removing Oil Carbon Residue From Cylinder Wall
G03164013Courtesy of BMW OF NORTH AMERICA, INC.

Unscrew conrod bearing cover.

Fig 4: Unscrewing Conrod Bearing Cover
G03164014Courtesy of BMW OF NORTH AMERICA, INC.

Insert special tool 11 3 480 in conrod.

Fig 5: Inserting Special Tool 11 3 480
G03164015Courtesy of BMW OF NORTH AMERICA, INC.

Remove conrod with piston from cylinder head side.

Lift out retaining ring and press out piston pin.

IMPORTANT: Piston and piston pin are paired and must not be fitted individually.
Fig 6: Identifying Piston And Piston Pin
G03164016Courtesy of BMW OF NORTH AMERICA, INC.

Installation: 

Installation of pistons is described separately from removal. The assembly sequence differs between removal and installation.

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 7: Identifying Piston Pin
G03164017Courtesy of BMW OF NORTH AMERICA, INC.

Measure piston installation clearance:

Measure piston diameter with micrometer at distance A from the underside of the piston and at offset angle of 90° to piston pin axis.

Fig 8: Measuring Piston Diameter With Micrometer
G03164018Courtesy of BMW OF NORTH AMERICA, INC.

Measurement A for M54, refer to ENGINE - TECHNICAL DATA (M54) . For other engine variants, see TECHNICAL DATA .

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.

Fig 9: Adjusting Micrometer
G03164019Courtesy of BMW OF NORTH AMERICA, INC.

Diameter of cylinder bore for M54, refer to ENGINE - TECHNICAL DATA (M54) . For other engine variants, see TECHNICAL DATA .

Piston installation clearance for M54, refer to ENGINE - TECHNICAL DATA (M54) . For other engine variants, see TECHNICAL DATA .

Total permissible wear tolerance for M54, refer to ENGINE - TECHNICAL DATA (M54) . For other engine variants, see TECHNICAL DATA .

Replace conrod bearing shells.

IMPORTANT: Piston and piston pin are paired and must not be fitted individually.

Fit conrod with piston pin to piston in such a way that both of the visible pair numbers on the installation direction arrow on the piston point to the right.

Fig 10: Identifying Piston And Piston Pin
G03164020Courtesy of BMW OF NORTH AMERICA, INC.

Install snap ring so that opening is opposite recess.

Fig 11: Installing Snap Ring
G03164021Courtesy of BMW OF NORTH AMERICA, INC.

Insert special tool 11 2 470 in conrod.

Fig 12: Inserting Special Tool 11 2 470
G03164022Courtesy of BMW OF NORTH AMERICA, INC.

Lightly coat pistons and piston rings with oil.

Align contact points on piston rings (offset at approx. 120°, but do not arrange over piston pin lug).

NOTE: Piston diameter 84 mm: Use special tool 11 8 141. Piston diameter 80 mm: Press together piston rings with special tool 11 2 260.
Fig 13: Pressing Together Piston Rings With Special Tool 11 2 260
G03164023Courtesy of BMW OF NORTH AMERICA, INC.

Install piston so that arrow points to camshaft drive.

Entire circumference of tightening strap must rest firmly on engine block.

IMPORTANT: Danger of piston ring failure.

Press in piston only with finger force (do not knock in!).

Fig 14: Pressing In Piston Only With Finger Force
G03164024Courtesy of BMW OF NORTH AMERICA, INC.

Attach crankpin to connecting rod.

Fig 15: Attaching Crankpin To Connecting Rod
G03164025Courtesy of BMW OF NORTH AMERICA, INC.

Apply light coat of oil to connecting-rod bearing shells.

Fit bearing caps so that pair numbers match up.

Install new conrod bolts.

Fig 16: Installing New Conrod Bolts
G03164026Courtesy of BMW OF NORTH AMERICA, INC.

Tighten down conrod bolts with special tool 00 9 120 or special tool 11 2 110.

Fig 17: Tightening Down Conrod Bolts With Special Tool 00 9 120
G03164027Courtesy of BMW OF NORTH AMERICA, INC.

Tightening torque, refer to 11 24 1AZ in ENGINE - TIGHTENING TORQUES .

Install oil pump.

If oil pump and oil scraper are two parts: Fit oil scraper.

Assemble engine.

Fig 18: Identifying Nut
G03164028Courtesy of BMW OF NORTH AMERICA, INC.
scientia non olet · About LEMON Manuals