Removing and Installing/Replacing Exhaust Camshaft

11 31 028 Removing And Installing / Replacing Exhaust Camshaft (N55)

Special tools required:







IMPORTANT:
It is absolutely essential to follow an exact procedure for removing and installing the exhaust camshaft.
Risk of damage.
The upper and lower bearing strips must be preloaded with a total of six special tools 11 8 550.







Necessary preliminary tasks:
- Remove cylinder head cover.
- Remove all ignition coils and injector shafts.
- Remove exhaust camshaft adjuster
- Adjust valve timing.







Position special tool 11 7 100 on cylinder 2.
Hand-tighten special tool 11 7 100 with special tool 11 8 552.







NOTE: Graphic without bearing strip.

Screw in roller cam follower at 2nd cylinder using spindle nut of special tool 11 7 100 to end stop.







Release screw connection on bearing strip in sequence from 15 to 1.
Remove upper bearing strip (1).

NOTE: The upper and lower bearing strips (1) can also be lifted out completely with exhaust camshaft.







Remove exhaust camshaft (1) from bearing strip in direction of arrow.
Set down exhaust camshaft (1) on special tool.







IMPORTANT:
Marks of intake and exhaust camshafts are different.
Mixing up the intake and exhaust camshaft will result in engine damage.

A = Exhaust camshaft.
E = Intake camshaft







IMPORTANT:
Plain rectangular compression rings (1) can easily break.
Plain rectangular compression rings (1) are engaged at joint.
Press plain rectangular compression rings (1) apart upwards and downwards and removed towards front.

Installation note:
Modify plain rectangular compression ring on new exhaust camshaft.

IMPORTANT:
Removal on engine:
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.

IMPORTANT: Special tool 11 8 552 is a special screw.

Press down rocker arms (3) on cylinder no. 2 with spindle nut (2) of special tool 11 7100 .







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.

NOTE: Graphic of intake camshaft.







The cam (1) at cylinder 6 points downward at an angle.







IMPORTANT:
There must be no oil residues in the cylinder head threaded holes.
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.







NOTE:
Schematic diagram of special tool 11 8 553 at upper bearing strip (1) and lower bearing strip (2).
Preload all special tools 11 8 553with special tool 11 4 350 only.

IMPORTANT: Tighten screw (3) on synchronizing key to 2 Nm. Risk of damage.







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).

IMPORTANT: Tighten screws on synchronizing key to 2 Nm. Risk of damage.







IMPORTANT:
Set special tool 11 8 553 to 2 Nm.
Preload all special tools 11 8 553with 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.

IMPORTANT: Remove special tool 11 8 553 only when exhaust camshaft screw connection is completed.







Assemble engine.