LEMON Manuals: Even more car manuals for everyone
Home >> Mini >> 2010 >> Cooper S, 2D Hatchback, Standard >> Repair and Diagnosis >> External Pages >> Different car >> Section 4204 (Engine - Pistons, Piston Rings, Balancing Shafts, Rocker Arms, Intake / Exhaust Valves, Valve Springs, Valve Stem Seals, Variable Valve Lift Control System (VALVETRONIC) - Repair) >> Pistons And Piston Rings >> N20 Engine >> 11 25 530 Removing and installing/replacing all pistons (N20)

11 25 530 Removing and installing/replacing all pistons (N20)

WARNING: This page does not describe the selected car, but rather 50 other vehicles, including the 2016 BMW M5, 2016 BMW ActiveHybrid 5, 2016 BMW 550i xDrive, 2016 BMW 550i, and 2016 BMW 535i xDrive. However, it is still accessible from the selected car via links, so may be relevant.

Special tools required: 

WARNING: Safety goggles must be worn when working on the piston pin circlip.
IMPORTANT: If pistons, connecting rods and bearing shells are reused, they must be reinstalled in the same places.
Piston and gudgeon pins are paired and must not be fitted individually.
Individual connecting rod replacement is not permitted; they are classified by weight class.
Connecting rods and connecting rod bearing caps are marked with the same pairing letters; mixing them up will result in engine damage.

Necessary preliminary tasks: 

NOTE: In event of heavy oil carbon residue:

Carefully remove oil carbon residue from cylinder wall.

NOTE: Graphic N46.
Fig 1: Locating Carbon Residue On Cylinder Wall
G09920590Courtesy of BMW OF NORTH AMERICA, INC.
IMPORTANT: Do not  release screw (1).
OIL SPRAY NOZZLE (2) must not be maladjusted or bent.
If necessary, readjust (risk of damage)  .
Fig 2: Identifying Oil Spray Nozzle And Screw
G09920591Courtesy of BMW OF NORTH AMERICA, INC.

Release connecting rod bolts (1).

Tightening torque 11 24 1AZ .

Remove connecting rod bearing cap (2).

IMPORTANT: Connecting rods and connecting rod bearing caps are marked with the same pairing letters; mixing them up will result in engine damage.
Fig 3: Identifying Connecting Rod Bearing Cap And Bolts
G09920592Courtesy of BMW OF NORTH AMERICA, INC.

Screw special tool 11 8 590 into big end of connecting rod.

Press out connecting rod and piston to cylinder head side.

IMPORTANT: Risk of damage  to oil spray nozzle.
Fig 4: Installing Special Tool (11 8 590) Into Big End Of Connecting Rod
G09920593Courtesy of BMW OF NORTH AMERICA, INC.
WARNING: Safety goggles  must be worn for the next operation.
WARNING: Safety goggles  must be worn.

To lever out piston circlip (1), support with special tool 11 4 492 on piston (2).

Lever out piston circlip (1) with special tool 11 4 492 in direction of arrow.

Fig 5: Removing Piston Circlip Using Special Tool (11 4 492)
G09920594Courtesy of BMW OF NORTH AMERICA, INC.
IMPORTANT: Connecting rods are divided into weight classes and are only available as a set.
Old and new connecting rods must not be installed in mixed combinations.

Installation note: 

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

Fig 6: Identifying Gudgeon Pin
G09920595Courtesy of BMW OF NORTH AMERICA, INC.

Measure the PISTON INSTALLATION CLEARANCE :

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

Piston diameter at measuring point A.

Fig 7: Measuring Piston Diameter Using Micrometer
G09920596Courtesy of BMW OF NORTH AMERICA, INC.

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

DIAMETER OF CYLINDER BORE .

PERMISSIBLE TOTAL WEAR CLEARANCE .

Installation note: 

If necessary, replace piston  .

Fig 8: Adjusting Micrometer To Cylinder Bore Of Engine Block
G09920597Courtesy of BMW OF NORTH AMERICA, INC.

Clamp special tool 11 5 341 in a vice.

NOTE: Piston and gudgeon pin are optimized to each other.

Screw in suitable special tool 11 5 342 with dia. 10.7 in special tool 11 5 341 .

Fig 9: Clamping Special Tool (11 5 341) In Vice And Fitting Special Tool (11 5 342)
G09920598Courtesy of BMW OF NORTH AMERICA, INC.

Secure piston (1) with connecting rod to special tool 11 5 341 .

Fig 10: Securing Piston And Connecting Rod To Special Tool (11 5 341)
G09920599Courtesy of BMW OF NORTH AMERICA, INC.
IMPORTANT: Safety goggles must be worn.

Lift out circlip and press out piston pin.

Fig 11: Removing/Installing Circlip
G09920600Courtesy of BMW OF NORTH AMERICA, INC.
WARNING: Safety goggles  must be worn.
IMPORTANT: The opening of the piston pin circlip must be installed on the piston in the 6 o'clock position  .
Risk of damage! 

Insert piston circlip (2) into groove of special tool 11 8 562 .

Bring piston circlip (2) into working position (1).

Fig 12: Identifying Piston Circlip Working Position
G09920601Courtesy of BMW OF NORTH AMERICA, INC.
WARNING: Safety goggles  must be worn.

Slide on special tool 11 8 564 up to piston pin circlip (1)

Special tools 11 8 562 and 11 8 564 are prepared.

Fig 13: Identifying Piston Pin Circlip And Special Tools (11 8 564 And 562)
G09920602Courtesy of BMW OF NORTH AMERICA, INC.
WARNING: Safety goggles  must be worn.

Opening on special tool 11 8 562 must point to piston crown; only then can special tool 11 8 564 be fitted correctly.

If the special tools 11 8 562 and 11 8 564 are not positioned correctly, the piston pin circlip must be driven in using a plastic hammer in direction of arrow.

NOTE: See Fig 14.

Graphic with special tool 11 4 491

Fig 14: Positioning Special Tools
G09920603Courtesy of BMW OF NORTH AMERICA, INC.

Install all PISTON RINGS .

Install all BEARING SHELLS .

Coat piston and piston rings with oil.

Pre-install piston (2) in special tool 11 8 141 .

Screw on special tool 11 8 590 in connecting rod (2).

Installation note: 

Make sure protective lugs (1) on special tool 11 8 590 are positioned correctly and check for damage.

Fig 15: Installing Piston In Special Tool (11 8 141) And Positioning Protective Lugs Of Special Tool (11 8 590)
G09920604Courtesy of BMW OF NORTH AMERICA, INC.

Insert piston with connecting rod in cylinder.

IMPORTANT: Risk of damage to oil spray nozzle.
Risk of breakage of piston rings.
Only press pistons into place with finger force - do not knock in!

Insert piston so that arrow on piston crown points to camshaft drive.

Press in piston (1) with special tool 11 8 141 .

Fig 16: Inserting Piston With Arrow On Piston Crown Pointing Toward Camshaft Drive
G09920605Courtesy of BMW OF NORTH AMERICA, INC.
IMPORTANT: Connecting rod and connecting rod bearing cap are marked with pairing letters (1) and must not be mixed up.
Swapping or incorrectly fitting the connecting rod bearing cap on the big end will result in engine damage  .
Fig 17: Identifying Pairing Letters For Connecting Rod And Bearing Cap
G09920606Courtesy of BMW OF NORTH AMERICA, INC.

Apply a light coat of oil to crankshaft journals.

Attach connecting rod to crankshaft journal.

Screw off special tool 11 8 590 in counter-clockwise direction.

NOTE: Graphic N54.
Fig 18: Installing Special Tool (11 8 590) Into Big End Of Connecting Rod
G09920607Courtesy of BMW OF NORTH AMERICA, INC.

Fit bearing caps (2) so that pairing letters match up.

Install new connecting rod bolts (1).

Join connecting rod bolts (1).

Tightening torque 11 24 1AZ .

Fig 19: Identifying Connecting Rod Bearing Cap And Bolts
G09920608Courtesy of BMW OF NORTH AMERICA, INC.

Secure connecting rod bolts (1) with special tool 00 9 120 .

Tightening torque 11 24 1AZ .

Fig 20: Tightening Connecting Rod Bolts Using Special Tool (00 9 120)
G09920609Courtesy of BMW OF NORTH AMERICA, INC.

Assemble engine.

scientia non olet · About LEMON Manuals