11 25 000 Removing and installing or replacing all pistons (B48B)

WARNING: This page is about a different car, the 2018 BMW 330i and 2017 BMW 330i. However, it is still accessible from the selected car via links, so may be relevant.

Special tools required:

11 8 860
2 360 584
11 4 492
11 6 240

WARNING: Protective goggles must be worn when working on the gudgeon pin circlamp.

Necessary preliminary work:

Attention!

If pistons, connecting rods and connecting rod bearing shells are reused, they must be reinstalled in the same places.

Individual connecting rod replacement is not permitted; they are classified by weight class.

Connecting rods and connecting rod bearing caps are denoted with the same pairing letters. Mixing up the components will result in engine damage.

Piston and gudgeon pins are paired and must not be fitted individually or confused.

When replacing a piston, it is absolutely necessary to replace all other pistons as well.

The replacement of an individual piston is not permitted!

Removal:

Unscrew all bolts.

Remove reinforcement (1).

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Attention!

Position crankshaft (1) vertically.

Proceed with care at the cylinder wall and oil spray nozzles Risk of damage!

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Undo the connecting rod bolt (1).

Remove connecting rod bearing caps (2) and set down in neat order.

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Remove connecting rod bearings (1) and set down in neat order.

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Screw special tool 11 8 860 in at large connecting rod eye.

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Remove piston (1) with connecting rod.

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NOTE: Fixtures (1) for special tool 2 360 584 .

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Prepare special tool 2 360 584 with fixtures (1).

NOTE: Ø for fixtures (1) = 12.5 mm.

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WARNING: Safety goggles must be worn for the next operation.

Position piston (1) with connecting rod (2) on special tool 2 360 584 .

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WARNING: Safety goggles must be worn.

Lift off gudgeon pin circlip (1) from piston over groove (2) using special tool 11 4 492 .

Attention!

Piston and gudgeon pin are matched to each other.

They must not be mixed up.

Pay attention to installation position of piston and connecting rod.

Piston and connecting rod must not be installed with a rotational misalignment of 180 degree to each other.

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Check if the gudgeon pin (1) has noticeable play in the piston.

Check whether gudgeon pin (1) can be removed without excessive force.

Result:

Gudgeon pin (1) is difficult to remove or gudgeon pin (1) has noticeable play.

Measure:

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Replace the piston (2) and gudgeon pin (1).

Remove gudgeon pin (1) from piston (2) and connecting rod (3) in the direction of the arrow.

Installation:

Before installation, measure 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.

Distance A.

Refer to ENGINE BLOCK - TECHNICAL DATA .

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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.

Refer to ENGINE BLOCK - TECHNICAL DATA .

Piston installation clearance:

Refer to PISTONS AND PISTON RINGS - TECHNICAL DATA .

Total permissible wear tolerance:

Refer to PISTONS AND PISTON RINGS - TECHNICAL DATA .

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Clean and oil connecting rod bearing.

If necessary, replace CONNECTING ROD BEARING .

Attention!

Piston and gudgeon pin are matched to each other.

They must not be mixed up.

Pay attention to installation position of piston and connecting rod.

Piston and connecting rod must not be installed with a rotational misalignment of 180 degree to each other.

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NOTE: It must be possible to the press gudgeon pin (1) through the connecting rod (small connecting rod eye) with little force; it must not reveal any noticeable play.

WARNING: Safety goggles must be worn for the next operation.

Position connecting rod (2) in piston (1).

Position piston (1) with connecting rod on special tool 2 360 584 .

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Pre-tension gudgeon pin circlip (1) in special tool 2 360 584 .

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NOTE: Make sure the tool is positioned correctly.

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Attention!

Insert the circlip (1) in a way that the opening (2) points towards the piston crown.

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Attention!

Risk of damage on piston and gudgeon pin!

Drive in gudgeon pin circlip in the direction of the arrow by means of slight hammer blows .

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Align contact points of PISTON RINGS (offset at approx. 120°, but do not arrange over gudgeon pin boss).

Coat piston (1) and piston rings with oil.

Prepare piston (1) with piston rings on special tool 11 6 240 .

Screw special tool 11 8 860 on at large connecting rod eye.

NOTE: Make sure CONNECTING ROD BEARING (2) is in proper installation position.

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Attention!

Oil spray nozzles (2) must not be maladjusted or bent.

A bent oil spray nozzle cannot be adjusted and must be replaced.

Release screw (1) and remove oil spray nozzle (2).

Tightening torque 11 42 10AZ .

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NOTE: Pay attention to the protective edge for the cylinder wall.

Insert piston so that the arrow points in direction of cylinder 1.

Position piston with connecting rod in special tool 11 6 240 and insert into cylinder.

Attention!

Risk of piston ring breakage.

Risk of damage to oil spray nozzle.

Only press pistons in with finger force - do not knock in!

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Slide connecting rod eye onto crankshaft.

Remove special tool 11 8 860 from large connecting rod eye.

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Insert CONNECTING ROD BEARING SHELL (1) into connecting rod bearing cap (2).

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Clean and oil connecting rod bearing.

If necessary, replace CONNECTING ROD BEARING .

Mount connecting rod bearing caps so that pairing letters (1) match.

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Installation note:

When installing new connecting rod bolts, it is imperative to make sure that 2 of the same connecting rod bolts are used at all times.

A mixed installation of connecting rod bolts (A) and (B) on the same connecting rod bearing cap is not permitted.

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Parts: Replace connecting rod bolt (1).

Tighten connecting rod bolts (1).

Tightening torque: 11 24 1AZ .

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Parts: Replace screws.

Install reinforcement (2).

Tighten down all screws.

Tightening torques: 11 41 3AZ and 11 41 4AZ .

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Required reworking:

Install OIL-/VACUUM PUMP
Mounting the CYLINDER HEAD
Remove ENGINE FROM ASSEMBLY STAND
Install ENGINE
Check engine function and check for tightness