11 24 571 Replacing all connecting rod bearings (N52)

Special tools required:

00 2 590
00 9 120

IMPORTANT: All crank pins are connected with the crankshaft.

Modified procedure; the bearing shell colours are the same at the top and bottom.

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

Necessary preliminary tasks:

Remove all Pistons.

IMPORTANT: Note Grinding Stages On Crankshaft.

Reworking (5) as per table (lift bearing).

B = construction stage 1 (- 0.25 mm)

C = construction stage 2 (- 0.50 mm)

Fig 1: Identifying Bearing Identification Tag

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IMPORTANT: All crankshaft crank pins are classified.

Possible classifications per connecting rod at top and bottom:

r: Red

b: Blue

Fig 2: Identifying Crankshaft Crank Pins

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

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

Example:

Possible classification: rbbrrb.

Cylinder classification Red.

Cylinder classification Blue.

Cylinder classification Red.

Cylinder classification Blue.

Install new conrod bearing shells.

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

Fig 3: Identifying Connecting Rod Bearing Shells

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Check conrod bearing clearance.

Piston in BDC position.

Fit special tool 00 2 590 (Plastigage Type PG 1) to oilfree crankshaft.

Fit bearing cap so that pairing letters match up.

Fig 4: Locating Conrod Bearing Clearance

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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. For tightening torque refer to 11 24 1AZ in 11 24 CONNECTING RODS AND BEARINGS (N52) .

Fig 5: Identifying Special Tool (00 9 120)

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

Conrod Bearing Clearance.

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

For tightening torque refer to 11 24 1AZ in 11 24 CONNECTING RODS AND BEARINGS (N52) .

Fig 6: Checking Connecting Rod Bearing Clearance With Measuring Scale

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Assemble engine.