11 31 028 Removing and installing/replacing exhaust camshaft (N55)
Special tools required:
Risk of damage!
The upper and lower bearing strips must be preloaded with a total of six special tools 11 8 550 .
Necessary preliminary work
- Remove CYLINDER HEAD COVER .
- Remove ALL IGNITION COILS AND INJECTOR SHAFTS .
- Remove EXHAUST CAMSHAFT ADJUSTER .
- Adjust VALVE TIMING .
Remove fitting bushes (1).
Installation note:
Check fitting bushes (1) for damage and replace if necessary.
Position special tool 11 7 100 on cylinder 2.
Hand-tighten special tool 11 7 100 with special tool 11 8 552 .
Screw in roller cam follower at 2nd cylinder to end stop using spindle nut of special tool 11 7 100 .
Release screw connection on bearing strip in sequence from 15 to 1.
Remove upper bearing strip (1).
Remove exhaust camshaft (1) from bearing strip in direction of arrow.
Set down exhaust camshaft (1) on special tool.
Mixing up the intake and exhaust cams result in engine damage .
A = Exhaust camshaft.
E = Intake camshaft
Metal plain rectangular compression ring
Only replace plain rectangular compression rings (1) when they are broken.
The plain rectangular compression rings have catches at the joint.
Press plain rectangular compression rings (1) apart upwards and downwards and removed towards front.
Make sure plain rectangular compression rings (1) can move freely.
Installation note:
When exhaust camshafts are inserted, no joint must point to a separating joint.
Plastic plain rectangular compression ring
Installation note:
The plastic plain rectangular compression ring is maintenance free and does not have to be replaced.
Insert plastic rectangular compression ring (1) into groove of exhaust camshaft (2) (see arrow).
Lightly oil plastic rectangular compression ring (1) and rotate in direction of arrow until compression ring (1) is positioned on the exhaust camshaft.
Check plastic plain rectangular compression ring (1 and 2) for freedom of movement.
Set engine to ignition TDC at cylinder No. 1.
Removed cylinder head:
When using special tool 11 9 000 , it will be necessary to remove the aluminium strip.
Installation note:
Before mounting the exhaust camshaft, ensure the correct fit of the rocker arm (1) on the hydraulic valve clearance compensating element and the valve.
See "Removing and installing/replacing all ROLLER CAM FOLLOWERS ".
Mounting bearing strip
Pre-install special tool 11 7 100 on cylinder no. 2.
Press down rocker arms (3) on cylinder no. 2 with spindle nut (2) of special tool 11 7 100 .
Position lower bearing strip (1) with exhaust camshaft (2) on rocker arms.
Align exhaust camshaft (2).
Cylinder nos. 2 and 4 are at valve overlap.
Cams (3) on cylinder no. 1 point upwards at an angle.
Part number (4) on mounting flats of exhaust camshaft (2) points upwards.
Insert exhaust camshaft so that none of the latching mechanisms for the plain rectangular compression rings (1) point to a bearing cap joint.
Centre latch mechanism of the plain rectangular compression rings with the bearing cap.
Insert exhaust camshaft so that the data code (1) on the mounting flats faces up.
The cam (1) at cylinder 6 points downward at an angle.
Clean threaded holes .
Fit upper bearing strip (1).
Insert bolts dry.
Join exhaust camshaft to lower and upper bearing strips (1) with torque wrench (2) to 8 Nm in sequential order from 1 to 15.
Release all screws of upper bearing strip (1) from outside inwards by 90°.
Installation note:
Upper and lower bearing strips must be aligned to each other at ground surfaces (1 and 2).
Make sure that the synchronizing key and the shanks of special tools 11 4 461 rest on the milled surfaces.
Preload all special tools 11 8 553 with special tool 11 4 350 only.
Position special tool 11 8 553 over screw connection of bearing strips.
Make sure that the shanks rest exactly on the ground surfaces of the upper bearing strip (2) and lower bearing strip (1).
Initially tighten screw of special tool 11 8 553 to ground surfaces of upper bearing strip (1) and lower bearing strip (2).
Preload all special tools 11 8 553 with special tool 11 4 350 only.
Mount special tools 11 8 553 to inside of cylinder head with pressure bolt.
Mount special tool 11 8 553 on cylinder no. 2 with pressure bolt facing outward.
Position special tools 11 8 553 so that screw connections (2) of bearing strip are easily accessible.
Tighten top and bottom bearing strip with special tool 00 9 120 .
Tightening torque 11 31 1AZ .
Assemble engine.