11 25 530 Removing and installing or replacing all pistons (M52/S52/M52TU/M54/M56): Installation

Installation of pistons is described separately from removal. The assembly sequence differs between removal and installation.

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

Fig 1: Checking Piston Pin Play

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Measure piston installation clearance:

Measure piston diameter with micrometer at distance A from the underside of the piston and at offset angle of 90° to piston pin axis.

Measurement A. Refer to 11 25 Pistons with Rings and Pins M54 B 30 in ENGINE - TECHNICAL DATA .

Fig 2: Measuring Piston Diameter

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

Diameter of cylinder bore. Refer to 11 11 Engine Block, Cylinder Crankcase M54 B 30 in ENGINE - TECHNICAL DATA .

Piston installation clearance. Refer to 11 25 Pistons with Rings and Pins M54 B 30 in ENGINE - TECHNICAL DATA .

Total permissible wear tolerance. Refer to 1 25 Pistons with Rings and Pins M54 B 30 in ENGINE - TECHNICAL DATA .

Fig 3: Measuring Diameter Of Cylinder Bore

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Replace conrod bearing shell, refer to 11 24 571 REPLACING ALL CONNECTING ROD BEARINGS (M52/S52/M52TU/M54/M56) .

Fit conrod with piston pin to piston in such a way that both of the visible pair numbers on the installation direction arrow on the piston point to the right.

Fig 4: Identifying Conrod With Piston Pin Installed Position

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Install snap ring so that opening is opposite recess.

Fig 5: Installing Piston Pin Snap Ring

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Insert special tool 11 2 470 in conrod.

Fig 6: Fitting Special Tool To Conrod

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Lightly coat pistons and piston rings with oil.

Align contact points on piston rings (offset at approx. 120°, but do not arrange over piston pin lug).

Use special tool 11 8 141.

Piston diameter 80 mm:

Press together piston rings with special tool 11 2 260.

Fig 7: Installing Piston Rings Tool

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Install piston so that arrow points to camshaft drive.

Entire circumference of tightening strap must rest firmly on engine block.

Press in piston only with finger force (do not knock in!).

Fig 8: Fitting Piston To Engine Block

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Attach crankpin to connecting rod.

Fig 9: Attaching Crankpin To Connecting Rod

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Apply light coat of oil to connecting-rod bearing shells. Fit bearing caps so that pair numbers match up.

Install new conrod bolts.

Fig 10: Installing Conrod Caps

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Tighten down conrod bolts with special tool 00 9 120 or special tool 11 2 110.

Tightening torque, refer to 11 24 1AZ in ENGINE MECHANICAL - TIGHTENING TORQUES - 530I (E39) .

Fig 11: Tightening Conrod Bolts

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Install oil pump, refer to 11 41 000 REMOVING AND INSTALLING/REPLACING OIL PUMP (M52TU/M54/M56) .

If oil pump and oil scraper are two parts:

Fit oil scraper.

Fig 12: Fitting Oil Scraper

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Assemble engine.