11 24 571 Replacing all connecting rod bearings (N54, N54T)

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IMPORTANT: All crank pins are connected with the crankshaft.

Blue/Red bearing shell colors are no longer used in combination.

Necessary preliminary tasks:

Remove all PISTONS .

IMPORTANT: All crankshaft crank pins are classified.

Bearing shell colors are different in the connecting and in the connecting rod bearing cap.

Possible classifications per connecting rod at top and bottom:

r: Connecting rod = Yellow.

Connecting rod bearing cap = Red.

b: Connecting rod = Violet.

Connecting rod bearing cap = Blue.

Fig 1: Direction Of Fitting Color In Connecting Rod And Connecting Rod Bearing Cap

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Only one color may be fitted per connecting rod and connecting rod bearing cap.

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

Example:

Possible classification: rbbrrb.

Zyl 1: Classification r = rod side Yellow bearing cap side Red.

Zyl 2: Classification b = rod side Violet bearing cap side Blue.

Zyl 3: Classification b = rod side Violet bearing cap side Blue.

Zyl 4: Classification r = rod side Yellow bearing cap side Red.

Zyl 5: Classification r = rod side Yellow bearing cap side Red.

Zyl 6: Classification b = rod side Violet bearing cap side Blue.

Install new connecting rod bearing shells.

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

Fig 2: Identifying Bearing Shell Colors

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Check connecting rod bearing clearance.

Piston in BDC position.

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

Fit bearing cap so that pairing letters match up.

Fig 3: Locating Bearing Cap Pairing Letters

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IMPORTANT: Do not distort connecting rods or crankshaft.

Use the old connecting rod bolts to check connecting rod clearance.

Tighten down connecting rod bolts with special tool 00 9 120 .

Tightening torque 11 24 1AZ .

Fig 4: Tightening Connecting Rod Bolts

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

CONNECTING ROD BEARING PLAY.

Remove plastic thread
Coat crankshaft and bearing shells with oil.
Install new connecting rod bolts and tighten down with special tool 00 9 120 .

Tightening torque 11 24 1AZ .

Fig 5: Checking Connecting-Rod Bearing Play

Courtesy of BMW OF NORTH AMERICA, INC.

Assemble engine.