Installation

Installation
(Inlet Or Exhaust Side As Applicable)
The inlet or exhaust camshaft can be replaced in the vehicle.

Caution: Incorrect assembly/removal without special tools exposes the camshaft to the risk of preliminary damage or breakage. The valves may also be bent by contact with the piston crown. Comply without fail with the job instructions, recommended special tools and work sequence.

Installation of camshafts is described separately from removal.
The assembly sequence for removal and installation is different.

Note: Camshafts, bearings and bearing caps, friction washers, all splines on toothed shafts and spline hubs must be oiled before installation.

Caution: The bucket tappets expand when not subjected to load by the camshaft and therefore require some time before they can be pushed back down. During a rapid assembly sequence, the "closed" valves may still be open and be in contact with the piston.

Comply with following waiting periods after installing camshaft and before cranking engine back to TDC position.
- Room temperature (20°C) 4 min.s
- 10°C...20°C 11 min.s
- 0°C ... 10°C 30 min.s.





Pull up timing chain and feed in exhaust camshaft.
Position timing chain on exhaust camshaft.





Install camshafts so that cam tips on inlet and exhaust valves on 1st cylinder face one another.





Fit bearing cover.

Note:
The bearing covers are clearly marked and can be read from the exhaust end:
A1 through A7 for the exhaust end
E1 through E7 for the intake end





Fit special tool 11 3 260 to cylinder head and screw into spark plug threads in cylinders 1 and 4.





Turn the eccentric shaft to pre-tension the bearing caps.
Tighten down bearing cover.
Tightening torque, refer to Specifications, Mechanical.
Remove special tool 11 3 260.





Caution:
Do not damage the cylinder head.
Machine open-end wrench accordingly if necessary.

Align camshafts with open-end wrench.





Fit special tool 11 3 240 to camshafts on cylinder 6. Align camshafts so that special tool 11 3 240 rests without gaps on cylinder head.





Attach special tool 11 3 244 to special tool 11 3 240 and locate by way of spark plug thread.





Lift timing chain and hold under tension.
Rotate engine from the 30° before TDC position in direction of rotation up to TDC position.





Secure crankshaft in TDC position with special tool 11 2 300.

Caution: Remove special tool 11 2 300 before starting engine.





Position sensor gear on inlet camshaft.





Fit thrust washer and tighten down with dowels.
Tightening torque, refer to Specifications, Mechanical.





Feed chain wheel onto timing chain so that arrow on chain wheel faces separating face of upper side of cylinder head.





Insert special tool 11 4 220 in cylinder head and bring adjustment screw into contact with tensioning rail, but do not pretension timing chain yet.
Check arrow on chain wheel to separating face of upper side of cylinder head, reposition chain wheel if necessary.





Insert and tighten down screw-in pin.
Tightening torque, refer to Specifications, Mechanical.





Install secondary chain tensioner.





Fit toothed sleeve (6) and align to toothed shaft in camshaft so that tooth gaps are opposed.





Secure toothed shaft (5).
Insert pin of toothed shaft (5) into tooth gaps of splines on camshaft and toothed sleeve (6).





Push in toothed shaft (5) until the longitudinal holes in the toothed sleeve (6) are positioned centrally with respect to the thread.





Place chain wheels in special tool 11 6 180, position tooth gap on inlet chain wheel as shown in illustration and feed on chain.





Caution: Do not alter position of chain wheels with respect to chain when removing from special tool 11 6 180.

Remove chain with chain wheels in position from special tool 11 6 180 and fit so that tooth gaps on inlet side are opposed.





Align chain with chain wheels so that tooth gaps on inlet side are exactly opposed.





Secure toothed shaft (4).
Insert pin of toothed shaft (4) into tooth gaps of splines on camshaft and chain wheel.





Push in toothed shaft (4) until approx. 1 mm of splines can still be seen.





Note installation direction of corrugated washer (7), "FRONT" lettering must be visible.
Install corrugated washer, tighten nuts by hand but do not tighten down fully yet.





Insert screws on exhaust side, initially tighten to approx. 5 Nm and then release again by half a turn.





Fit thrust washer (3).





Note installation direction of cup spring (2), "F" lettering must be visible.

Note:
If "F" lettering is no longer visible on an engine that has been run:
Install cup spring (2) so that small locating diameter of spring (2) points to sensor gear.
Fit cup spring (2) in position.





Position sensor gear (1) so that arrow on sensor gear faces separating face of upper side of cylinder head.
Install nuts and tighten by hand but do not tighten down fully yet.





Withdraw toothed shaft (5) up to stop.





Press down secondary chain tensioner at top and remove special tool 11 3 292.





Preload tensioning rail with special tool 11 4 220 by rotating adjusting screw with special tool 00 9 250 or standard torque wrench to 0.7 Nm.





Preload cup spring slightly by pressing on sensor gear (1) and tighten nuts by hand.

Caution: Do not tighten down nuts fully.





Remove gasket.
Check dowel sleeves (1) for damage and correct installation position.
Keep sealing face clean and free of oil.





Caution: Fit special tool 11 6 150 "without gasket" only.

If gasket remains underneath special tool 11 6 150, camshaft timing will be "incorrectly" set.
Attach special tool 11 6 150 "without gasket", tighten nuts by hand and then tighten down uniformly until special tool 11 6 150 is in full contact with cylinder head.





Bring screws (1) on exhaust side into contact by initially tightening to approx. 5 Nm.





Bring nuts (2) on exhaust side and nuts (3) on inlet side into contact by initially tightening to approx. 5 Nm.





Tighten down screws (1) on exhaust side.
Tightening torque, refer to Specifications, Mechanical.





Tighten down nuts (2) on exhaust side and nuts (3) on inlet side.
Tightening torque, refer to Specifications, Mechanical.





Pull special tool 11 2 300 back until flywheel is no longer secured in position.





Remove special tool 11 3 244 and special tool 11 3 240.





Crank engine twice in direction of rotation until cam tips on inlet and exhaust camshafts on 1 st cylinder face one another.





Secure crankshaft in TDC position with special tool 11 2 300.

Caution:
Do not turn the engine back.
Remove special tool 11 2 300 before switching on the engine.





Fit special tool 11 3 240 to camshafts.





Note: In spite of correctly set camshafts, special tool 11 3 240 may protrude by up to 1 mm over inlet side.

Reason:
^ Rubberized chain wheel
^ Tolerances in VANOS adjustment unit
^ Running clearance in splines
If special tool 11 3 240 protrudes above the exhaust side, it will be necessary to readjust the timing.





Remove special tool 11 6 150.
Install VANOS adjustment unit. Service and Repair
Assemble engine.