11 31 025 Removing and installing/replacing intake camshaft (N54/N54T)

WARNING: This page is about a different variant/trim than selected.

Special tools required:

IMPORTANT: Risk of damage!
It is absolutely essential to follow an exact procedure for removing and installing the exhaust camshaft.
The upper and lower bearing strips must be pre-tensioned with a total of six special tools 11 8 553 .
Special tool 11 8 550 can be used for intake and exhaust sides.

Necessary preliminary tasks:

Remove CYLINDER HEAD COVER
Remove INTAKE ADJUSTER of intake camshaft

Release bearing cap screw connections from outside inwards.

Lift out lower and upper bearing strips (1) with camshaft.

NOTE: Graphic shows N52.

Fig 1: Removing Camshaft Upper And Lower Bearing Strips

Remove upper bearing shell.

Remove intake camshaft (1) marked with (E).

Fig 2: Identifying Intake Camshaft Marking

IMPORTANT: Both camshafts have different markings.
Mixing up the two camshafts will result in engine damage.

A Exhaust camshaft

E Intake camshaft

Fig 3: Identifying Exhaust And Intake Camshaft

Metal plain rectangular compression ring:

IMPORTANT: Plain rectangular compression rings (1) can easily break.

Only replace plain rectangular compression rings (1) when they are broken.

The plain rectangular compression rings have catches at the joint.

Press the plain rectangular compression rings (1) apart forwards and towards the rear and remove towards the front.

Make sure plain rectangular compression rings (1) can move freely.

Installation note:

When intake camshafts are inserted, no joint must point to a separating joint.

Fig 4: Removing Plain Rectangular Compression Ring

Graphic N12 engine

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 plain rectangular compression ring (1) into groove of intake camshaft (2) (see arrow).

Lightly oil plastic plain rectangular compression ring (1) and rotate in direction of arrow until plastic plain rectangular compression ring (1) is positioned on the intake camshaft.

Make sure plain rectangular compression ring (1) can move freely.

Fig 5: Inserting Plastic Rectangular Compression Ring Into Exhaust Camshaft Groove

IMPORTANT: Removal on engine:
Engine at cylinder no. 1 firing TDC position.
Removed cylinder head:
When using special tool 11 9 000 , it will be necessary to remove the aluminium strip.

Installing camshaft bearing strip:

Pre-install special tool 11 8 551 on cylinder nos. 2 and 3.

Insert special tool 11 8 552 in screw connection of cylinder head cover.

Special tool 11 8 551 is marked with letters E and A.

E = Intake side

A = Exhaust side

Press down roller cam follower on cylinder no. 3 with spindle nut (2) of special tool 11 8 551 .

Fig 6: Pressing Roller Cam Follower On Cylinder Using Special Tool (11 8 552)

Installation note:

Before installing intake camshaft, make sure roller cam follower is correctly seated on hydraulic valve clearance compensating element and valve.

Fig 7: Identifying Roller Cam Follower

Installation note:

Pre-install bearing strip of intake camshaft.

Fig 8: Identifying Intake Camshaft Marking

Lubricate all bearing points in lower bearing strip with engine oil.

Installation note:

Lay intake camshaft (1) in bearing strip.

Rotate intake camshaft (1) at cylinder no. 1 into position (2).

Fig 9: Identifying Intake Camshaft Position

Installation note:

Lower and upper bearing strips must be aligned to each other at ground surfaces (1 and 2).

Bring thrust piece and legs of special tools 11 8 553 into contact at milled surfaces.

Fig 10: Identifying Upper And Lower Bearing Strips Alignment

NOTE: Schematic depiction of special tool 11 8 553 at lower bearing strip (1) and upper bearing strip (2).

IMPORTANT: Tighten screw (3) on synchronising key to 2 Nm.

Fig 11: Special Tool (11 8 553) And Bearing Strip (Top/Bottom) Schematic Diagram

Position special tool 11 8 553 over screw connection of bearing strips.

Make sure that legs come into exact contact on ground surfaces, lower bearing strip (1) and upper bearing strip (2).

Fig 12: Positioning Special Tool (11 8 553) Over Upper And Lower Bearing Strip

Initially tighten screw of special tool 11 8 553 to ground surfaces of lower bearing strip (1) and upper bearing strip (2).

IMPORTANT: Tighten screws on thrust piece to 2 Nm.

Fig 13: Positioning Special Tool (11 8 553) Screw Onto Lower And Upper Bearing Strips

IMPORTANT: Set special tool 11 4 350to 2 Nm.
Pre-tension all special tools 11 8 553 with special tool 11 4 350 only.

Fig 14: Identifying Special Tool (11 4 350)

Install upper and lower bearing strips (1).

Pre-install all special tools 11 8 553 .

IMPORTANT: Secure special tool 11 8 553 to max. 2 Nm.

Fig 15: Preinstalling Special Tools (11 8 553)

Install intake camshaft with bearing strips (1) on cylinder head.

Fig 16: Identifying Intake Camshaft Bearing Strips

Check position of intake camshaft (1) at cylinder no. 6.

Roller cam follower (2) is not actuated.

Fig 17: Identifying Intake Camshaft Position (Cylinder 6)

Tighten lower and upper bearing strips with special tool 00 9 120 .

Tightening torque 11 31 1AZ .

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

Fig 18: Tightening Lower And Upper Bearing Strips Using Special Tool (00 9 120)

Adjust VALVE TIMING .

Assemble engine.