Timing Chain: Service and Repair

11 31 051 - Replacing timing chain (N52)

Special tools required:
- 11 0 300 11 0 300 Plug Mandrel
- 11 4 280 11 4 280 Gauge
- 11 4 360 11 4 360 Removal and Mounting Fixture
- 11 4 362 11 4 360 Removal and Mounting Fixture
- 11 5 200 11 5 200 Spacer Ring
- 11 9 280 11 9 280 Holder

Necessary preliminary tasks:
- Remove cylinder head cover Service and Repair.
- Remove all spark plugs.
- Remove chain tensioner Service and Repair.
- Remove radial shaft seal Service and Repair at front.
- Remove belt tensioner Service and Repair.
- Remove vibration damper Service and Repair.

Remove fastener (1) in direction of arrow.

Installation:
Install fastener (1) with bore facing outwards.

Secure crankshaft during entire repair operation with special tool 11 0 300 11 0 300 Plug Mandrel.

Do not remove special tool 11 4 280 11 4 280 Gauge.

Important!
Do not remove special tool 11 0 300 11 0 300 Plug Mandrel to release central bolt (1).
Employ a second person for gripping when releasing central bolt (1).

Mount special tool 11 9 280 11 9 280 Holder on hub for vibration damper.

Release central bolt (1).
Tightening torque: 11 21 1AZ 11 21 Crankshaft and Bearings.
Remove central bolt with hub towards front.

Open plug (1).
Tightening torque: 11 31 6AZ 11 31 Camshaft.

Release screw (1) on chain drive at top.
Tightening torque: 11 31 2AZ 11 31 Camshaft.

Release screw (1) on chain drive at bottom.
Tightening torque: 11 31 3AZ 11 31 Camshaft.

Remove both adjusting units Removing and Installing/Replacing Inlet and Exhaust Adjustment Units.
Release screws (1).
Tightening torque: 11 31 2AZ 11 31 Camshaft.
Remove timing chain module with timing chain and sprocket wheel upwards in direction of arrow.

Important!
Note installation direction of sprocket wheel (2).
Collar (see arrow) on sprocket wheel (2) points to crankshaft.
Incorrect assembly will result in engine damage.

Pull timing chain (1) upwards until sprocket wheel (2) engages chain guide (3).
Install timing chain (1) and sprocket wheel (2) in this position.

Installation:
Always keep timing chain tensioned; it is possible for timing chain (1) to jam on chain module (3).

Install hub with central bolt.
Tighten down special tool 11 5 200 11 5 200 Spacer Ring with screws (1).

Remove belt tensioner Service and Repair.
Screw in special tool 11 4 360 11 4 360 Removal and Mounting Fixture.
Mount special tool 11 9 280 11 9 280 Holder on 11 5 200 11 5 200 Spacer Ring.
Support special tool 11 9 280 11 9 280 Holder on special tool 11 4 362 11 4 360 Removal and Mounting Fixture.
Special tool 11 0 300 11 0 300 Plug Mandrel secures crankshaft.
Tighten central bolt (1) to jointing torque.
Tightening torque: 11 21 1AZ 11 21 Crankshaft and Bearings.
Mark central bolt and hub with paint.

Apply stroke of paint (1) for torsion angle tightening to tool.
See illustration.

Important!
Do not remove tool from central bolt during torsion angle tightening - risk of damage.

Tighten central bolt with two persons.
Tightening torque: 11 21 1AZ 11 21 Crankshaft and Bearings.
Install both adjusting units Removing and Installing/Replacing Inlet and Exhaust Adjustment Units.
Install chain tensioner Service and Repair.

Crank engine twice.
Check timing Testing and Inspection.
Assemble engine.