1124571 Replacing all connecting rod bearings (N51)

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2011 BMW 328xi, 2011 BMW 328i, 2010 BMW 328xi, 2010 BMW 328i, and 2009 BMW 328xi. However, it is still accessible from the selected car via links, so may be relevant.

IMPORTANT: All crank pins are connected with the crankshaft.
Modified procedure; the bearing shell colors are the same at the top and bottom.
Blue/Red bearing shell colors are no longer used in combination.

Necessary preliminary tasks:

Removing OIL PAN .

IMPORTANT: All crankshaft crank pins are classified.

Possible classifications per connecting rod at top and bottom:

r: Red

b: Blue

Only one color may be fitted per big end and connecting rod.

In direction of arrow from (1 to 2) crank pin (1 to 6).

Example:

Possible classification: rbbrrb.

Fig 1: Fitting Color In Connecting Rod

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Cylinder 1: Classification Red/Red.

Cylinder 2: Classification Blue/Blue.

Cylinder 3: Classification Blue/Blue.

Cylinder 4: Classification Red/Red.

Cylinder 5: Classification Red/Red.

Cylinder 6: Classification Blue/Blue.

Release conrod bolts (1).

Remove connecting rod bearing cap (2).

Fig 2: Identifying Connecting Rod Bearing Caps And Connecting Rod Bolts

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IMPORTANT: Risk of damage to cylinder wall and to crankshaft.

Gently release connecting rod from crankshaft.

Remove bearing shells (1 and 2).

Install new conrod bearing shells.

Installation:

Pay attention to guide lugs during installation.

Fig 3: Identifying Bearing Shell

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IMPORTANT: All crankshaft crank pins are classified.

In each case insert only one color of bearing shell (1 and 2) for each conrod.

Check conrod bearing clearance.

Piston in BDC position.

Determine bearing clearance, ensure that bearing points are free from oil and grease.

Fit special tool 00 2 590 (Plastigage Type PG 1) to oil-free crankshaft.

Fit bearing cap so that pairing letters match up.

Fig 4: Locating Bearing Cap Pairing Letters

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IMPORTANT: Do not distort conrods or crankshaft.
Use the old conrod bolts to check conrod clearance.
Tighten down conrod bolts with special tool 00 9 120 .
TIGHTENING TORQUE 11 24 1AZ .

Fig 5: Tightening Connecting Rod Bolts Using Special Tool (00 9 120)

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Remove bearing cap. Read off bearing clearance at width of crushed plastic thread (Plastigage) with aid of measuring scale.

Conrod bearing clearance.

Remove Plastigage
Coat crankshaft and bearing shells with oil.
Install new conrod bolts and tighten down with special tool 00 9 120 .

TIGHTENING TORQUE 11 24 1AZ .

Fig 6: Locating Connecting Rod Bearing Clearance

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Assemble engine.