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11 25 530 Removing and installing/replacing all pistons (W10)

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NOTE:

For Special Tool identification, see ENGINE- SPECIAL TOOLS - COOPER (1.6L) R50/W10 and MAINTENANCE AND GENERAL INFORMATION - SPECIAL TOOLS - COOPER (1.6L) R50/W10 .

Special Tools Required: 

Necessary Preliminary Tasks: 

IMPORTANT: Reinstall piston and conrod at the same point in the same installation position. Conrod and piston pin are press-fitted to each other. They cannot be disassembled (risk of damage  ). Mixing up conrod bearing caps with the conrod will result in engine damage.  Replace all connecting rod bolts.
IMPORTANT: Conrods and conrod bearing caps are not marked and must be marked with light center punch marks on the side. Conrods and conrod bearing caps must not be mixed up. See Fig 1.
Fig 1: Identifying Marks On Conrods And Conrod Bearing Caps
G03306152Courtesy of BMW OF NORTH AMERICA, INC.

Release screws (1).

Remove conrod bearing cap (2).

NOTE: All conrods are cracked. 

Do not  mix up conrods and conrod bearing caps.

Fig 2: Removing Conrod Bearing Cap
G03306153Courtesy of BMW OF NORTH AMERICA, INC.

Fit special tool 11 6 390 on conrod (1).

Pull out conrod (1) with piston to cylinder head side.

IMPORTANT: Do not damage cylinder wall when pulling out conrod with piston.
Fig 3: Removing Conrod With Piston
G03306154Courtesy 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.

Fig 4: Measuring Piston Diameter With Micrometer
G03306155Courtesy 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.

Total permissible wear tolerance.

Fig 5: Measuring Cylinder Bore Diameter
G03306156Courtesy of BMW OF NORTH AMERICA, INC.

Fit special tool 11 6 390 on conrod.

Lightly coat pistons and piston rings with oil.

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

Press together piston rings using special tool 11 2 260.

IMPORTANT: Danger of piston ring failure. 
Fig 6: Fitting Special Tool 11 6 390 On Conrod
G03306157Courtesy of BMW OF NORTH AMERICA, INC.

Insert piston so that arrow (1) points to cam drive.

IMPORTANT: Press in piston with a hammer-style action - do not  knock in.
Fig 7: Identifying Piston Position
G03306158Courtesy of BMW OF NORTH AMERICA, INC.

Position conrod with special tool 11 6 390 on crankshaft journal.

Remove special tool 11 6 390.

IMPORTANT: Note installation position of bearing shells. Refer to 11 24 571 REPLACING ALL CONNECTING ROD BEARINGS (W10) .
Fig 8: Positioning Conrod With Special Tool 11 6 390 On Crankshaft Journal
G03306159Courtesy of BMW OF NORTH AMERICA, INC.

Install conrod bearing cap (2) with conrod bearing shells.

Tighten conrod bearing bolts (1) hand-tight.

Fig 9: Installing Conrod Bearing Cap Bolts
G03306160Courtesy of BMW OF NORTH AMERICA, INC.

Tighten down conrod bolts with special tool 00 9 120.

Tightening torque: 11 24 1AZ in ENGINE - TIGHTENING TORQUES- COOPER (1.6L) R50/W10 .

Fig 10: Tightening Conrod Bolts With Special Tool 00 9 120
G03306161Courtesy of BMW OF NORTH AMERICA, INC.

Assemble engine.

Installation: 

Lubricate all crankshaft bearing positions with engine oil.

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