11 31 028 Removing and installing/replacing exhaust 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.
Top and bottom bearing strips must be pre-tensioned with a total of six special tools 11 8 553 .

NOTE: Special tools 11 8 551 , 11 8 552 and 11 8 553 are included in set of special tools 11 8 550 .

Necessary preliminary tasks:

Remove CYLINDER HEAD COVER
Remove EXHAUST ADJUSTING UNIT for exhaust camshaft.
Adjust VALVE TIMING

Release bearing cap screw connections from outside inwards.

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

NOTE: Graphic N52.

Fig 1: Removing Camshaft Bearing Cap Screw Connections

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

A Exhaust camshaft.

E Intake camshaft

Fig 2: Identifying Exhaust And Intake Camshaft Markings

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.

Fig 3: Removing Plain Rectangular Compression Ring

Installation note:

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

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 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.

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

Fig 4: 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.

Installation note:

Before installation of exhaust camshaft, make sure roller cam follower is correctly fitted on hydraulic valve clearance compensating element and valve!

Fig 5: Identifying Roller Cam Follower

Installing camshaft bearing strip:

Preassemble special tool 11 8 551 on 2nd cylinder.

Observe markings E and A

E: Intake side

A: Exhaust side

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

Press down roller cam follower (1) on 2nd cylinder with spindle nut of special tool 11 8 551 .

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

Lay lower bearing strip (1) on cylinder head.

Installation note:

Lubricate all bearing positions with engine oil.

Fig 7: Identifying Cylinder Head Lower Bearing Strip

Insert exhaust camshaft (1) in lower bearing strip.

Installation note:

Lubricate all bearing positions and cams with engine oil.

Fig 8: Identifying Exhaust Camshaft

Installation position (1) of exhaust camshaft (2) at cylinder no. 1.

Fig 9: Identifying Exhaust Camshaft Installation Position

Join exhaust camshaft to lower and upper bearing strips with torque wrench from inside outwards to 8 Nm.

Release all screws of bearing strip (1) from outside inwards by 90°.

Check position of exhaust camshaft (2) at cylinder no. 6.

Roller cam follower (1) is not actuated.

Fig 10: Identifying Exhaust 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 shanks of special tools 11 8 553 into contact at milled surfaces.

Fig 11: Identifying Upper And Lower Bearing Strips Alignment

NOTE: Schematic diagram of special tool 11 8 553 at top bearing strip (2) and bottom bearing strip (1).

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

Fig 12: Special Tool (11 8 553) And Bearing Strip (Top/Bottom) Schematic Diagram

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

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

Fig 13: Positioning Special Tool (11 8 553) Over Upper And Lower Bearing Strip

Position screw of special tool 11 8 553 on ground surfaces of bottom bearing strip (2) and top bearing strip (1).

IMPORTANT: Tighten screws on synchronising key to 2 Nm.

Fig 14: Positioning Special Tool (11 8 553) Screw Onto Bottom And Top Bearing Strips

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

Fig 15: Identifying Special Tool (11 4 350)

Fit special tools 11 8 553 with screw (1) to the inside of the cylinder head.

On 2nd cylinder fit special tool 11 8 553 with screw (1) facing outwards.

Position special tools 11 4 350 so that screw connections (2) of bearing strip are easily accessible.

Fig 16: Installing Special Tool (11 4 350) Onto Second Cylinder

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

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

Tightening torque 11 31 1AZ .

IMPORTANT: Only remove special tool 11 8 553 when camshaft screw connection is completed.

Fig 17: Tightening Camshaft Screw Connection Using Special Tool (00 9 120)

Assemble engine.