Upper Section of Timing Case

Preliminary Work
Remove both cylinder heads, refer to Cylinder Head Assembly.
Remove fan clutch with fan impeller and fan cowl, refer to Cooling System.
Remove non-return valve for cylinder group 1 to 6.
Remove both distributor housings, this task is described in the work step, Replacing radial seal in left distributor housing, refer to Powertrain Management.
If necessary, remove sensor for cylinder detection (camshaft sensor), refer to Powertrain Management.

Removal
Removal and installation of the upper timing case are described separately.

Unfasten screw on oil drip tray guide.

Remove screw cover from oil filler plug and unfasten screw.

Unfasten screws.

Note: Bracket (1) for secondary air induction pipe.

Unfasten screws. Remove top section of timing case.

Note: Bracket (1) for secondary air induction pipe.

Remove guide rail from timing chain (belt).

Rotate engine at central bolt in direction of rotation until the first cylinder is in TDC firing position.

Note: When the first cylinder is in TDC firing position, the recess on the flange of the camshaft (1) is flush with the bolt connection of the oil baffle (2).

Remove dust cover from locating bore. Secure crankshaft with special tool 11 2 300 in TDC firing position.

Caution: Remove special tool prior to operating engine.

Secure both camshafts with special tool 11 3 190 in TDC firing position.

Note: Crankshaft and camshaft remain secured until completion of conversion work.

Press off retaining cap (1) from chain tensioner with screwdriver.

Loosen lock nut (2) and unfasten adjusting screw (1) a few turns.

Caution: Screw plug (3) is spring-loaded - compression spring jumps out!

Carefully unscrew and remove screw plug (3).

Unfasten screws on left and right sprocket wheels.
Secure chain to prevent it from dropping.

Unfasten screw (1) on sliding rail. Pull sliding rail upwards to remove and withdraw lower retaining tab.

Loosen screws (1).

Loosen screws (1).
Lift timing case upwards to remove.

Installation
Removal and installation of the upper timing case are described separately.

Sealing surfaces on both cylinder banks clean and free of oil.

Caution: Note installation direction of seals.

Insert seals so that sealant bead (1) faces timing case.

Check that dowel sleeves are undamaged and correctly located.
Replace seals (1 and 2) on both cylinder banks.

Sealing surfaces on both cylinder banks clean and free of oil.
Attach gasket round chain and apply thin, uniform coat of Hylomar SQ 32 M (or equivalent) above and below the attachment point.

1. Fit timing case
2. Insert all screws in cylinder heads and in lower timing case and fill flush.
3. Tighten up screws under timing case
4. Tighten down cylinder head screws.

Tightening torque, refer to Engine, Specifications.

Caution: If all screws are tightened, they must be tightened again in a second operation.

Before installing sprocket wheel for cylinder bank 7 to 12, sensor gear (1) for camshaft cylinder recognition must be fitted.

Note: The sensor gear (1) is secured in the camshaft with a lug.

Fit left and right sprockets to the camshaft, align long bores, insert screws in sprockets and fit flush.

Arrangement of Components:
1. Adjusting screw
2. Lock nut
3. Screw plug
4. Sealing ring (replace)
5. O-ring (replace)
6. Dowel sleeve
7. Compression spring (cylindrical part of compression spring must face chain tensioning piston)
8. Chain tensioning piston

Install chain tensioning piston with guide lugs (1) in the bow cover, insert compression spring and screw plug (2) and tighten down.
Tightening torque of screw plug, refer to Engine, Specification.

Adjusting chain tensioner:
Press bow cover once briefly towards the chain and measure dimension (A). Press bow cover firmly back against spring force and measure dimension (B).
Subtract dimension (B) from dimension (A).
Adjust nominal value (6 ± 0.5 mm) with adjusting screw and tighten down lock nut.

Install new retaining cap (1).

1. Tighten down sprocket screws on cylinder bank 7 to 12.
2. Tighten down sprocket screws on cylinder bank 1 to 6.
Tightening torque, refer to Engine, Specifications.

Insert timing chain guide rail.

Insert guide rail from above and secure with retaining tab.

Note: When timing case cover is fitted, retaining tab is not visible.

Insert screw (1)and tighten down.

Keep sealing faces clean and free of oil.
Check dowel sleeves (1) for damage and correct installation position.
Coat upper and lower edges of joint with Hylomar SQ 32 M (or equivalent).

Replace all seals.

Caution: Note installation direction of seals.

Insert all seals so that sealant bead (1) faces timing case cover.

Note: Secure seals with Hylomar SQ 32 M.

Fit timing-chain cover.
Insert screw in oil filler plug and fit flush.

Insert screw into oil drip tray guide and fit flush.

Insert screws and fit flush.

Note: Bracket (1) for secondary air induction pipe.

Insert screws.

Note: Bracket (1) for secondary air induction pipe.

Tighten down all screws on upper timing case cover.
Tightening torque, refer to Engine, Specifications.

Caution: If all screws are tightened, they must be tightened again in a second operation.

Assemble engine.