11 31... Service solution - replacing intake camshaft (N20, N26)

Special tools required:

WARNING: Risk of injury in event of incorrect use.

IMPORTANT: Improper handling. Risk of damage!

Necessary preliminary tasks:

Removal:

NOTE: Injector shafts shown removed for purposes of clarity.

IMPORTANT: Secure eccentric shaft (1) with open-end spanner (3) (risk of return stroke).

Fig 1: Securing Eccentric Shaft With Open-End Spanner

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Slowly adjust eccentric shaft (1) to minimum lift via servomotor using 4-mm hexagon socket wrench (2) and open-end spanner (3).

Release bolt (1) on the oil spray nozzle.

Tightening torque: 11 37 4AZ .

Unclip oil spray nozzle (2) from the bracket on the actuator drive (3) in direction of arrow.

Fig 2: Releasing Oil Spray Nozzle From Bracket On Actuator Drive

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Position special tool 11 7 110 on return spring (1) (see arrows).

Fig 3: Return Springs

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WARNING: Risk of injury in event of incorrect use.

IMPORTANT: Improper handling. Risk of damage!

Fig 4: Turning Knurled Screw Using Special Tool (11 7 110)

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Place special tool 11 7 110 flat on cylinder head.

Turn knurled screw (1) in direction of arrow until both clamping levers secure return spring in gate.

Return spring is correctly preloaded when both clamping levers are parallel to guide block.

Fig 5: Special Tool (11 7 110) Flat On Cylinder Head

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IMPORTANT: Risk of damage!

Left and right return springs (1) must be positioned in lateral guide of special tool 11 7 110 .

Fig 6: Return Springs Position In Special Tool (11 7 110) Lateral Guide

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Preload return spring with lever (1) on special tool 11 7 110 in direction of arrow.

Fig 7: Positioning Return Spring With Lever On Special Tool (11 7 110)

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Lock special tool 11 7 110 with catch on lever (1).

IMPORTANT: Screw connection on throttle return spring can only be released with secured special tool 11 7 110 .

Fig 8: Catch On Lever

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Release screw (1).

Fig 9: Screw And Special Tool (11 7 110)

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WARNING: Risk of injury in event of incorrect use.
Lever (1) is preloaded.

IMPORTANT: Improper handling. Risk of damage!

Fig 10: Pressing Back Latching Hook Using Special Tool (11 7 110)

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Secure lever (1).

Press back latching hook (2).

Return spring tension can now be released.

Release knurled screw (1) on special tool 11 7 110 in direction of arrow.

Fig 11: Releasing Knurled Screw On Special Tool (11 7 110)

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Release special tool 11 7 110 in direction of arrow from return spring (1).

Fig 12: Releasing Special Tool (11 7 110) From Return Spring

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Return springs (1) remain on the engine.

Fig 13: Engine Return Springs

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NOTE: All bearing caps are identified with numbers from 1 to 4.

The front bearing cap is a thrust bearing and does not have an identification.

Release screws on all bearing caps (1 to 10).

Set down all bearing caps in a tidy and orderly fashion on special tool 11 4 481 .

Fig 14: Intake Camshaft Bearing Caps Bolts Tightening/Loosening Sequence (N20, N26)

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IMPORTANT: Do not remove intermediate levers (2). Mixing up the intermediate levers (2) will cause the engine to suffer idle-speed fluctuations.

Remove intake camshaft.

Fig 15: Intermediate Levers

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Installation:

Fig 16: Intake And Exhaust Camshafts Marks

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IMPORTANT: Marks of intake and exhaust camshafts different.
Mixing up the intake and exhaust camshafts result in engine damage.
A Exhaust camshaft.
E Intake camshaft

Insert intake camshaft so that data code (1) on mounting flats points upwards.

Fig 17: Exhaust Camshaft Data Code

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Position intake camshaft so that cams point downward at an angle and to the left.

Fig 18: Intake Camshaft Cams

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NOTE: All bearing caps are identified with numbers from 1 to 4.

Fig 19: Right Intake Camshaft Bearing Cap Bolts Tightening/Loosening Sequence (N20)

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The front bearing cap is a thrust bearing and does not have an identification.

Insert screws on all bearing caps from (10) to (1).

Tightening torque: 11 31 3AZ .

Position special tool 11 7 110 on return spring.

Fig 20: Positioning Special Tool (11 7 110) On Return Spring

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Clamp throttle return spring with knurled screw (1) in direction of arrow.

Fig 21: Fitting Throttle Return Spring With Knurled Screw

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Return spring (1) is positioned correctly when latching hooks surround return spring (1).

Fig 22: Positioning Return Spring

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WARNING: Risk of injury in event of incorrect use.

IMPORTANT: Improper handling. Risk of damage!
Check return spring on intermediate lever to ensure correct installation position.

Press special tool 11 7 110 to stop in direction of arrow.

Fig 23: Pressing Special Tool (11 7 110) To Stop

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Install return spring (2) on gate.

IMPORTANT: Insert return spring (2) in intermediate lever (1) (see arrow).
Check that rocker arm (3) is in correct installation position.

Fig 24: Inserting Return Spring In Intermediate Lever

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IMPORTANT: Check that intermediate lever (1) is installed in correct position on eccentric shaft (2).

Fig 25: Intermediate Lever And Eccentric Shaft

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IMPORTANT: Observe thread on cylinder head.
Risk of damage!

Tighten bolt (1).

Tightening torque: 11 37 2AZ .

Fig 26: Bolt And Special Tool (11 7 110)

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WARNING: Risk of injury in event of incorrect use.
Lever (1) is preloaded.

IMPORTANT: Improper handling. Risk of damage!

Fig 27: Pressing Back Latching Hook Using Special Tool (11 7 110)

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Secure lever (1).

Press back latching hook (2).

Return spring tension can now be released.

Check installation position of intermediate lever and return spring again, remove special tool 11 7 110 .

Retract oil spray nozzle (2) on actuator drive (3).

Engage bolt (1) and release back to 90°.

For exact positioning of the oil spray nozzle (2) audibly clip it in at the top.

Tightening torque: 11 37 4AZ .

Fig 28: Releasing Oil Spray Nozzle From Bracket On Actuator Drive

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Required follow-up work:

Install INTAKE ADJUSTER .

Adjust VALVE TIMING .

Fit CYLINDER HEAD COVER .

Install DME CONTROL UNIT .