Removing and Installing Camshaft (Includes Adjusting Timing)-Engine Removed
WM 150520 Removing and installing camshaft (includes adjusting timing)-engine removed
Camshaft designation
Camshaft designation M97.20
Position of lettering: -arrows-
Position of camshaft designation
Camshaft lettering for cylinders 1-3:
^ Inlet camshaft: 987.035.04
^ Outlet camshaft: 987.065.04
Camshaft lettering for cylinders 4-6:
^ Inlet camshaft: 987.036.04
^ Outlet camshaft: 987.066.04 (with aluminum plugs)
Aluminium plugs in outlet camshaft 4 - 6
Additional identifying feature for outlet camshaft 4-6: Aluminum plugs with lubrication bore -1- for tandem pump.
Allocation of inlet camshaft adjusting device
Allocation of inlet camshaft adjusting device
Camshaft adjusting device on inlet camshaft, cylinder bank 1-3
Information
^ Side 1-3: the arrow should be attached in anti-clockwise position.
- Designation, side 1-3:
Designation of adjuster 1 - 3
^ Part number, cylinder bank, manufacturer information, direction of rotation of engine (arrow), production date.
Camshaft adjusting device on inlet camshaft, cylinder bank 4-6
Information
^ Side 4-6: the arrow should be attached in clockwise position.
- Designation, side 4-6:
Designation of adjuster 4 - 6
^ Part number, cylinder bank, manufacturer information, direction of rotation of engine (arrow), production date.
Allocation of chain tensioners
Allocation of chain tensioners
- Primary chain tensioner on crankcase (oil filter area), identification: one ring-Arrow-
Primary chain tensioner
- Chain tensioner on cylinder head, cylinder bank 1-3, identification: two rings -Arrows-
Chain tensioner, cylinders 1 - 3
- Chain tensioner on cylinder head, cylinder bank 4-6, no identification.
Chain tensioner 4 - 6
Preliminary work for removing camshafts
Preliminary work for removing camshafts
1. For disassembling cylinder side 1-3, loosen the ground cable on the cylinder head -arrow- by unscrewing a Torx screw (M8) and remove the cable. Disconnect oil pressure switch cable plug.
Engine ground strap
2. Remove ignition coils -1-. In each case unscrew two Torx socket screws M6 x 25 and pull the ignition coils out of the spark-plug recess.
Hydraulic valve for camshaft adjustment and ignition coils (Vario Cam version)
3. Remove solenoid hydraulic valve -1- (for camshaft adjustment).
Solenoid hydraulic valve for camshaft adjustment (Vario Cam version)
4. Vario Cam Plus only: Remove solenoid hydraulic valve for valve lift adjustment.
Overview, hydraulic valve for valve lift adjustment (Vario Cam Plus version)
5. Remove spark plugs.
6. Remove oil suction pump for cylinders 1-3. Unscrew four Torx screws M6 x 20 (micro-self-locking), remove oil suction pump, and replace O-ring and screws.
Oil suction pump for cylinders 1 - 3
7. Remove tandem pump for cylinders 4-6. Unscrew four Torx screws M6 (micro-self-locking) -1-. Pull off the vacuum line on pump -2-. Remove pump and replace O-rings and micro-self-locking screws.
Tandem pump side 4 - 6
Removing camshaft-engine removed
Removing camshafts
Caution
Risk of damage due to particles of dirt.
^ Danger of material damage due to blocked oil bores/oil ducts.
-> Absolute cleanliness is essential when working on the engine.
-> Lay removed engine parts on a clean base and make sure to cover them.
-> Use the cover for dust protection when fitting the engine NR.165 on the engine assembly support.
Caps
1. Remove the plastic caps on the cylinder head. Press a small screwdriver into the center of the piercing point of each cap and lever out the caps.
2. Turn the engine at the assembly support so that the cylinder bank to be worked on stands vertically upwards.
Cylinder bank 1-3:
Information
^ The engine must be always turned clockwise (running direction of engine) during assembly work on the timing drive mechanism.
^ Only turn engine using the crankshaft pulley, not at the camshafts.
3. Turn crankshaft at the pulley clockwise to the overlapping TDC of cylinder 1. Using a locating pin 9595/1 fix the pulley or vibration balancer.
TDC marking on pulley
4. The smaller cut-outs at the grooves of the inlet and outlet camshafts -arrows- must point to the cylinder head cover. Check the position using the adjusting gauge 9686 (-> Adjusting gauge 9686).
Position of the camshafts in overlapping TDC of cylinders 1 or 4
Adjusting gauge 9686
Information
^ Before disassembling the cylinder head cover, the central screw on the camshaft adjusting device must be unscrewed.
5. Unscrew the central screw on the camshaft adjusting device.
5.1. Retaining tool 9685 must be positioned on the hexagon of the adapter and the contact block placed as a counter on the fitting bore of the cylinder head cover for the oil suction pump; if necessary, position the contact block by undoing and tightening the screw.
5.2. If the special tool cannot be positioned on the hexagon of the adapter in this way, the engine must be turned further in the direction of rotation at the pulley of the crankshaft until the contact block comes into contact with the central screw of the cylinder head cover, ready for unscrewing. Unscrew the central screw.
Unscrewing central screw on camshaft adjuster
6. Remove cylinder head cover.
7. Release the four Torx screws M6 x 16 on the sprocket of the respective outlet camshaft. Do not remove the sprocket.
8. Remove chain tensioner for cylinders 1-3 -arrow-.
Chain tensioner, cylinders 1 - 3
9. Unscrew guide rail screw M6 on pulley side (hexagon socket a/f 5).
10. Unscrew four Torx screws for outlet camshaft sprocket. Lift timing chain off sprocket and remove the sprocket. Lay timing chain on the mounting tab for the sprocket.
11. Remove the four camshaft thrust bearings and the guide rail. Unscrew eight Torx screws, six M6 x 35 -1-, two M6 x 40 -2- (screws for guide rail). Lift the thrust bearing and the guide rail carefully off the bearing surfaces and the timing chain.
Camshaft bearing cover and guide rail
12. Remove the camshafts. Remove outlet camshaft, lift timing chain off the camshaft adjuster of the inlet camshaft and remove the camshaft. Lay the timing chain in the chain housing in the cylinder head.
Cylinder side 4-6:
Information
^ The engine must be always turned clockwise (running direction of engine) during assembly work on the timing drive mechanism.
^ Only turn engine using the crankshaft pulley, not at the camshafts.
13. Turn crankshaft at the pulley clockwise to the overlapping TDC of cylinder 4. Using a locating pin 9595/1 fix the pulley or vibration balancer.
TDC marking on pulley
14. The smaller cut-outs at the grooves of the inlet and outlet camshafts -arrows- must point to the cylinder head cover. Check the position using the adjusting gauge 9686 (-> Adjusting gauge 9686).
Position of the camshafts in overlapping TDC of cylinders 1 or 4
Adjusting gauge 9686
15. Unscrew central screw for camshaft adjuster element analogous to that for side 1-3.
16. Unscrew four Torx screws for outlet camshaft sprocket. Do not remove the sprocket.
17. Remove chain tensioner for cylinders 4-6 -arrow-.
Chain tensioner, cylinders 4 - 6
18. Unscrew guide rail screw M6 on pulley side (hexagon socket a/f 5).
19. Unscrew four Torx screws for outlet camshaft sprocket. Lift timing chain off sprocket and remove the sprocket. Lay timing chain on the mounting tab for the sprocket.
20. Remove the four camshaft thrust bearings and the guide rail. Unscrew eight Torx screws, six M6 x 35, two M6 x 40 (screws for guide rail). Lift the thrust bearing and the guide rail carefully off the bearing surfaces and the timing chain.
21. Remove the camshafts. Remove outlet camshaft, lift timing chain off the camshaft adjuster of the inlet camshaft and remove the camshaft. Lay the timing chain in the chain housing in the cylinder head.
Installing camshaft-engine removed
Installing camshafts-cylinders 4-6
Caution
Risk of damage due to particles of dirt.
^ Danger of material damage due to blocked oil bores/oil ducts.
-> Absolute cleanliness is essential when working on the engine.
-> Lay removed engine parts on a clean base and make sure to cover them.
-> Use the cover for dust protection when fitting the engine NR.165 on the engine assembly support.
Designation of housings of camshafts:
Designation of camshaft housing
Inlet camshaft:
^ Thrust bearing: 'E' and matching number on cylinder head/cylinder head cover
^ Housing of bearing sleeve: only matching number
Outlet camshaft:
^ Thrust bearing on sprocket: '1A' and matching number on cylinder head/cylinder head cover
^ 2nd thrust bearing: '2A' and matching number on cylinder head/cylinder head cover
Information
^ The engine must be always turned clockwise (running direction of engine) during assembly work on the timing drive mechanism.
^ Only turn engine using the crankshaft pulley, not at the camshafts.
1. To remove the play from the timing chain drive, turn the crankshaft by means of the pulley clockwise (running direction of engine until U6 marking on pulley coincides with fixing bore in crankcase (60° before TDC). Fix with locating pin 9595/1.
Pulley fixed at 60° before TDC
2. Turn the engine on the assembly support until cylinder bank 4-6 stands vertically upwards.
3. Oil the bearing surfaces of the camshafts with new engine oil.
4. Insert inlet camshaft 4-6. Pull the timing chain out of the chain housing of the cylinder head with a welding wire and position on the ring gear of the camshaft adjuster, at the same time inserting the camshaft at overlapping TDC of cylinder 4 (the cams of cylinder 4 point towards the bulkhead of the flat-base tappet housing -arrows-).
Cam positions with cylinder 4 overlapping (Vario cam)
Cam positions with cylinder 4 overlapping (Vario Cam Plus)
Information
^ Make sure that the bearing sleeve on the inlet camshaft is positioned correctly.
5. The bearing sleeve of the inlet camshaft must be positioned so that the centrally bored blind hole points vertically upwards -arrow- (the rib of the cylinder head should also be at the center in relation to the bearing sleeve).
In this position, the dowel pin in the bearing bore of the cylinder head will fit precisely into the opposite off-center blind hole bore. Any other bores are through-holes for guiding the oil.
Position of bearing sleeve for inlet camshaft (view of Vario Cam camshaft)
6. Insert outlet camshaft 4-6. Lay the timing chain on the flange for the sprocket, then insert the camshaft at overlapping TDC of cylinder 4 (the outlet cams of cylinder 4 point towards the cams of the inlet camshaft -arrows-).
Outlet camshaft 4 - 6
7. Insert outlet camshaft sprocket in the timing chain and position on camshaft flange. The four threaded bores in the camshaft flange must be covered approximately half way by the slots of the sprocket in the clockwise running direction of the engine - -arrows-.
Position of sprocket 4 - 6 at 60° before TDC
8. Oil the bearing surfaces of the camshafts with new engine oil.
Information
^ Do not interchange the thrust bearings of the inlet and outlet camshafts during assembly; observe identification markings.
9. Insert three thrust bearings and one housing -arrows- for the bearing sleeve of the camshafts together with the guide rail for the timing chain.
Installation position of housing
10. Insert eight housing screws.
10.1. Six M6 x 35 and two M6 x 40 Torx screws for camshaft bearing and guide rail.
Housing screws
10.2. Tighten screws evenly and just finger-tight.
Installing camshafts for cylinders 1 - 3
Caution
Risk of damage due to particles of dirt.
^ Danger of material damage due to blocked oil bores/oil ducts.
-> Absolute cleanliness is essential when working on the engine.
-> Lay removed engine parts on a clean base and make sure to cover them.
-> Use the cover for dust protection when fitting the engine NR.165 on the engine assembly support.
Information
^ Make sure that the bearing sleeve on the inlet camshaft is positioned correctly.
Information
^ Do not interchange the thrust bearings of the inlet and outlet camshafts during assembly; observe identification markings.
Designation of camshaft housing:
Designation of housings of camshafts:
Inlet camshaft:
^ Thrust bearing: 'E' and matching number on cylinder head/cylinder head cover
^ Housing of bearing sleeve: only matching number
Outlet camshaft:
^ Thrust bearing on sprocket: '1A' and matching number on cylinder head/cylinder head cover
^ 2nd thrust bearing: '2A' and matching number on cylinder head/cylinder head cover
1. Turn the engine on the assembly support until cylinder bank 1 - 3 stands vertically upwards.
Information
^ The engine must be always turned clockwise (running direction of engine) during assembly work on the timing drive mechanism.
^ Only turn engine using the crankshaft pulley, not at the camshafts.
2. To remove the play from the timing chain drive, turn the crankshaft by means of the pulley clockwise (running direction of engine until U6 marking on pulley coincides with fixing bore in crankcase (60° before TDC). Fix with locating pin 9595/1.
Pulley fixed at 60° before TDC
3. Oil the bearing surfaces of the camshafts with new engine oil.
4. Insert inlet camshaft 1-3. Pull the timing chain out of the chain housing of the cylinder head with a welding wire and position on the toothed ring of the camshaft adjuster. Then insert the camshaft at overlapping TDC of cylinder 1 (the cams of cylinder 1 point diagonally downwards towards the outside of the cylinder head -arrow-).
Inlet camshaft 1-3 in overlap (Vario Cam version)
Inlet camshaft 1-3 in overlap (Vario Cam Plus version)
Information
^ Make sure that the bearing sleeve on the inlet camshaft is positioned correctly.
5. The bearing sleeve of the inlet camshaft must be positioned so that the centrally bored blind hole points vertically upwards -arrow- (the rib of the cylinder head should also be at the center in relation to the bearing sleeve).
In this position, the dowel pin in the bearing bore of the cylinder head will fit precisely into the opposite off-center blind hole bore. Any other bores are through-holes for guiding the oil.
Position of bearing sleeve for inlet camshaft
6. Insert outlet camshaft 1 - 3. Lay the timing chain on the flange for the sprocket, then insert the camshaft at overlapping TDC of cylinder 1 (the cams of cylinder 1 point diagonally downwards towards the outside of the cylinder head).
Outlet camshaft 1-3 in overlap
7. Insert outlet camshaft sprocket into the timing chain and position on camshaft flange. The four threaded bores in the camshaft flange must be fully visible on the left at the slotted curves of the sprocket (-arrows-) so that the Torx screws M6 x 12 can still be positioned to fasten the sprocket.
Outlet sprocket 1 - 3 at 60° before TDC
Outlet sprocket 1 - 3, all screws fitted
Information
^ Do not interchange the thrust bearings of the inlet and outlet camshafts during assembly; observe identification markings.
8. Insert three thrust bearings and one housing -arrows- for the bearing sleeve of the camshafts together with the guide rail for the timing chain.
Installation position of housing
9. Insert eight housing screws (Torx): six M6 x 35 -1- and two M6 x 40 -2- for camshaft bearing and guide rail. Tighten screws evenly and just finger-tight.
Housing screws
Adjusting camshaft timing
Information
^ The engine must be always turned clockwise (running direction of engine) during assembly work on the timing drive mechanism.
^ Only turn engine using the crankshaft pulley, not at the camshafts.
Adjust timing, cylinder bank 4-6:
1. Align both camshafts. The small circular cut-outs must point upwards -arrows-.
Slot position of camshafts at overlap
2. Use special tool adjusting gauge 9686 to fix camshafts.
2.1. If necessary, turn the camshafts slightly using the gauge.
2.2. Insert adjusting gauge into camshaft slots. The flat tool surface with the lettering faces towards the observer.
2.3. Fasten gauge using a screw M8 (e.g. hexagon-head bolt M8 x 16). Tighten screw by hand only.
Position of adjusting gauge 9689
3. Fasten housing screws for the inlet and outlet camshafts and the auxiliary screw of the adjusting gauge.
Housing screws and mounted adjusting gauge
3.1. Turn the screws further alternately by approx. 90° each until the specified tightening torque is reached. This enables the camshafts to be mounted without any distortion.
3.2. Tighten housing screws M6 -1 and 2-. -> Tightening torque: 10 Nm (7.5 ftlb.)
3.3. Tighten fastening screw M8 -3- for adjusting gauge -4-. -> Tightening torque: 23 Nm (17 ftlb.)
4. Insert guide rail screw with a new O-ring and tighten (hexagon socket M6, a/f 5). Grease O-ring with Optimol MP3. -> Tightening torque: 10 Nm (7.5 ftlb.)
5. Fit the chain tensioner, side 4-6 (hexagon socket a/f 14). Fit chain tensioner with new aluminum sealing ring and tighten. -> Tightening torque: 80 Nm (59 ftlb.)
Chain tensioner, cylinders 4 - 6
Information
^ Position crankshaft above the pulley or vibration balancer before the final adjustment of the timing to the TDC marking.
6. Turn the crankshaft by means of the pulley or vibration balancer clockwise (running direction of engine) to TDC mark: 'TDC' marking on pulley/vibration balancer coincides with fixing bore in crankcase. Fix with a locating pin 9595/1.
Pulley fixed at TDC marking
7. Insert four Torx screws M6 at sprocket of outlet camshaft and tighten evenly in diagonally opposite sequence. -> Tightening torque: 14 Nm (10.5 ftlb.)
Outlet camshaft sprocket tightened
8. Tighten the central screw of the camshaft adjusting device.
8.1. Fit special tool retaining tool 9685 on hexagon of intermediate piece of the central screw.
8.2. Screw in the central screw gently by hand so that the loose contact block just touches the fitting bore of the oil suction pump. Fix the hexagon-head bolt to the contact block.
Contact block at fitting bore of cylinder head
9. Tighten the central screw in two stages. Initial tightening to the specified toque. -> Initial tightening: 50 Nm (37 ftlb.)
Fastening central screw of camshaft adjusting device.
Information
^ Before final tightening (torque angle) of the central screw, the special tool adjusting gauge 9686 must be removed.
10. Remove special tool adjusting gauge 9686. Undo the M8 screw and remove gauge.
11. Tighten central screw using torque angle wrench. -> Final tightening torque angle: 110°
Adjust timing, cylinder bank 1-3:
Information
^ Before final tightening (torque angle) of the central screw, the special tool adjusting gauge 9686 must be removed.
12. Final timing adjustment for cylinder bank 1-3 is analogous to that for cylinder bank 4-6.
13. Fit chain tensioner for side 1-3 (hexagon a/f 32) before turning crankshaft to the TDC mark. Fit chain tensioner with new sealing ring and tighten. -> Tightening torque: 80 Nm (59 ftlb.)
Chain tensioner, cylinders 1 - 3
After adjusting the timing, this should be re-checked.
14. Turn the engine two complete turns (720°) at the crankshaft pulley and fix at the TDC mark. Check camshaft position of cylinder bank 1-3 using the adjusting gauge 9686. Then turn a further 360° and check the camshaft position of cylinder bank 4-6.
Slot position of camshafts at overlap
Subsequent work for installing camshafts
Subsequent work for installing camshafts
1. Insert solenoid hydraulic valves and new seals for the spark-plug recesses. Fit new O-rings on both solenoid hydraulic valves and insert into the bores in the cylinder head (replace oil strainer). Grease O-rings using Optimol MP3.
Spark-plug recess seals and solenoid hydraulic valve for camshaft adjustment (Vario Cam version)
Spark-plug recess seals and solenoid hydraulic valves for camshaft adjustment and valve lift adjustment (Vario Cam Plus version)
2. Install cylinder head cover.
3. Fit oil suction pump (1-3) and tandem pump (4-6) with new, micro-self-locking Torx screws M6. Replace O-rings and grease with Optimol MP3. Mount vacuum line with new O-rings onto tandem pump. -> tightening torque: 10 Nm (7.5 ftlb.)
4. Fit new plastic caps dry on cylinder head. Tap in with a plastic hammer.
Caps
5. Fit ground strap to cylinder head 1-3 with Torx screw M8 x 20 and tighten. -> Tightening torque: 23 Nm (17 ftlb.)
6. Insert each ignition coil into its spark plug recess -1-, fit two M6 x 25 Torx socket screws and tighten. -> Tightening torque: 10 Nm (7.5 ftlb.)
Hydraulic valves for camshaft adjustment and ignition coils
7. Fit new retainer plates -> Retainer plates with seal in installation position and holders for the solenoid hydraulic valves-2-. -> Tightening torque: 10 Nm (7.5 ftlb.)
Hydraulic valves for camshaft adjustment (Vario Cam Plus version)
Retainer plates with seal in installation position
8. Connect cable plugs to the oil temperature switch for cylinder bank 1-3.
9. Complete the engine.