Removing and Installing Camshaft, Adjusting Timing - Engine Removed
Removing and installing camshaft, adjusting timing - engine removed
Camshaft designation M97/01
Information
Between the start of series production in April 2004 and August 2004, the camshaft manufacturer changed the lettering of the camshafts. In order to avoid a mixed installation, particular attention must be paid to the designation of engines installed in standard vehicles during this period.
Position of lettering: -Arrows-
Position of camshaft designation
Camshafts for cylinders 1-3:
^ Inlet camshaft: 997.105.211.01
^ Exhaust camshaft: 996.105.262.05 3,8 EX 1-3
^ Inlet camshaft (new): 997.105.047.00/02
^ Exhaust camshaft (new): 996.105.059.01 3.8 EX 1-3
Camshafts for cylinders 4-6:
^ Inlet camshaft: 997.105.213.01
^ Exhaust camshaft: 996.105.264.05 3,8 EX 4-6 (with aluminum plugs)
^ Inlet camshaft (new): 997.105.048.00/02
^ Exhaust camshaft (new): 996.105.060.01 3,8 EX 4-6 (with aluminum plugs)
Additional identifying feature for exhaust camshaft 4-6: aluminum plugs with lubrication bore for tandem pump
Aluminum plugs in exhaust camshaft 4-6
Allocation of inlet camshaft adjustment 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
- 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
1. Remove engine.
2. Remove rear muffler.
3. Remove cover plate for ignition coils -1-. Unscrew two M6 x 16 Torx screws and remove cover plate.
Cover plate and support for rear muffler
4. Remove support for rear muffler. Disconnect cable plugs of ignition coils and magnetic hydraulic valves.
Unscrew four Torx screws: intake side two M8 x 30, exhaust side two M8 x 25, remove support.
Rear muffler support
5. For disassembling cylinder bank 4-6, undo the ground cable on the cylinder head by unscrewing a Torx screw M8 and removing the cable. Disconnect two cable plugs from oil pressure switch.
6. 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 valves for camshaft adjustment and ignition coils
7. Remove solenoid hydraulic valves -2- (NVS and VHS).
8. Remove spark plugs.
9. 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
10. 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 camshafts - engine removed
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.
1. Turn the engine at the assembly support so that cylinder bank to be worked on stands vertically upwards.
2. 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 cap.
3. Disassembling cylinder bank 1-3 Turn crankshaft at the pulley/vibration balancer clockwise to the overlapping TDC of cylinder 1. Disassembling cylinder bank 4-6 Turn crankshaft to the TDC for cylinder 4. Using a locating pin 9595/1 fix the pulley or vibration balancer.
TDC marking on pulley
4. If the camshafts of cylinder bank 1-3 are removed, the smaller circular cut-outs at the grooves of the inlet and outlet camshafts -Arrows- of cylinder 1 must point to the cylinder head cover. For cylinder bank 4-6 the corresponding position is then on cylinder 4. Check the position using the adjusting gauge 9686.
Position of the camshafts in overlapping TDC of cylinders 1 or 4
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 adjustment device. Position retaining tool 9685 on the hexagon of the adapter and place the contact block 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. 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.
Unscrew the central screw on the camshaft adjuster.
6. Remove cylinder head cover.
7. Release the four Torx screws M6 x 16 on the sprocket of the respective exhaust camshaft. Do not remove the sprocket.
8. Remove chain tensioner for cylinders 1-3 or 4-6.
Chain tensioner, cylinders 1-3
Chain tensioner, cylinders 4-6
9. Cylinder bank 4-6 Unscrew guide rail screw M6 on pulley side (hexagon socket a/f 5).
10. Unscrew four Torx screws for exhaust 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, two M6 x 40 (screws for guide rail). Lift the thrust bearing and the guide rail carefully off the mounting points or timing chain.
12. Remove the camshafts. Remove exhaust 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, adjusting timing - engine removed
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.
Identification of housings of camshafts:
Identification 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
1. To remove the play from the timing chain drive, turn the crankshaft by means of the pulley or vibration balancer clockwise (running direction of engine to 60° before TDC: marking U6 on pulley or vibration balancer coincides with fixing bore in crankcase. Fix with locating pin 9595/1.
Pulley fixed at 60° before TDC
Assembly of cylinder bank 4-6
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-).
Inlet camshaft 4-6 in overlap
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 exhaust 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-).
Exhaust camshaft 4-6
7. Insert exhaust camshaft sprocket in the timing chain and position on camshaft flange. The four threaded bores in the camshaft flange must be covered by the slots of the sprocket in the clockwise running direction of the engine approximately half way -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 (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.
Position of housing screws
Adjust timing, cylinder bank 4-6
11. Align both camshafts. The small circular cut-outs must point upwards -Arrows-.
Slot position of camshafts at overlap
12. Using special tool adjusting gauge 9686, fix camshafts (if necessary with the gauge twisted) with an M8 screw (e.g. hexagon-head bolt M8 x 16). The flat tool face points upwards. Screw in fastening screw by hand.
Position of adjusting gauge 9689
13. Screw the housing screws of the inlet and exhaust camshafts and the auxiliary screw of the adjustment gauge alternately by approx. another 90° until the specified tightening torque is reached. -> Tightening torque: 10 Nm (7.5 ftlb.)
14. 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.)
15. Fit 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.
16. Turn the crankshaft by means of the pulley or vibration balancer clockwise (running direction of engine to TDC mark: marking U6 on pulley or vibration balancer coincides with fixing bore in crankcase. Fix with locating pin 9595/1.
Pulley fixed at TDC marking
17. Insert four Torx screws M6 to sprocket of exhaust camshaft and tighten evenly in diagonally opposite sequence. -> Tightening torque: 14 Nm (10.5 ftlb.)
Exhaust camshaft sprocket tightened
18. Tighten the central screw of the camshaft adjusting device. Fit special tool retaining tool 9685 on hexagon of intermediate piece of the central screw. 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 the fitting bore of the cylinder head
Information
^ Before final tightening (torque angle) of the central screw, the special tool adjusting gauge 9686 must be removed.
19. Tighten the central screw in two stages. -> Initial tightening to the specified toque. -> Initial tightening: 50 Nm (37 ftlb.)
Tighten central screw of camshaft adjusting device.
20. Remove special tool adjustment gauge 9686. Undo the M8 screw and remove gauge.
21. Apply final tightening to central screw with torque angle wrench. -> Final tightening torque angle: 110°
Assembly of cylinder bank 1-3
22. Turn the engine on the assembly support until cylinder bank 1-3 stands vertically upwards.
23. Turn the crankshaft by means of the pulley or vibration balancer clockwise (running direction of engine further still until the marking U6 on pulley or vibration balancer coincides with fixing bore in crankcase (60° before TDC). Fix with locating pin 9595/1.
Pulley fixed at 60° before TDC
24. Oil the bearing surfaces of the camshafts with new engine oil.
25. Insert inlet camshaft 1-3. Pull the control 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
Information
^ Make sure that the bearing sleeve on the inlet camshaft is positioned correctly.
26. 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
27. Insert exhaust camshaft 1-3. Lay the control chain on the flange for the chain 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).
Exhaust camshaft 1-3 in overlap
28. Insert exhaust camshaft sprocket in 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.
Exhaust sprocket 1-3 at 60° before TDC
Exhaust sprocket 1-3, all screws fitted
Information
^ Do not interchange the thrust bearings of the inlet and outlet camshafts during assembly; observe identification markings.
29. 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
30. 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.
Position of housing screws
Timing for side 1-3
Information
^ Position crankshaft above the pulley or vibration balancer before the final adjustment of the timing to the TDC marking.
Information
^ Before final tightening (torque angle) of the central screw, the special tool adjusting gauge 9686 must be removed.
31. Final timing adjustment for cylinder bank 1-3 is analogous to that for cylinder bank 4-6.;
32. 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, cylinder 1-3
After adjusting the timing, this should be re-checked.
33. Turn the engine 360° at the crankshaft and fix at the TDC mark. Check camshaft position of cylinder bank 4-6 using the adjusting gauge 9686. Then turn a further 360° and check the camshaft position of cylinder bank 1-3.
Slot position of camshafts at overlap
Subsequent work for installing camshafts
1. Insert solenoid hydraulic valves and new gaskets for the spark-plug recesses. Fit new O-rings into both solenoid hydraulic valves and insert into the bores in the cylinder head. Grease O-rings with Optimol MP3.
Gaskets for spark plug recess and solenoid hydraulic valves
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. -> Tightening torque: 10 Nm (7.5 ftlb.)
4. Fit new plastic cap dry on cylinder head. Tap in with a plastic hammer.
5. Fit ground strap to cylinder head 4-6 with Torx screw M8 x 20 and tighten. -> Tightening torque: 23 Nm (17 ftlb.)
6. Insert each ignition coil into its spark plug recess, fit two M6 x 25 Torx socket screws and tighten them. -> Tightening torque: 10 Nm (7.5 ftlb.)
7. Fit retainer plates and holders for the solenoid hydraulic valves. -> Tightening torque: 10 Nm (7.5 ftlb.)
8. Fit holder for rear muffler. Fit and tighten two Torx screws M8 x 30 intake side and two Torx screws M8 x 25 exhaust side. Fit cable plugs for ignition coils and solenoid hydraulic valves, fixing cable in the sheetmetal clips. -> Tightening torque: 23 Nm (17 ftlb.)
9. Fit and tighten cover plate with two Torx screws M6 x 16. -> Tightening torque: 10 Nm (7.5 ftlb.)
10. Connect two cable plugs to the oil temperature switch for cylinder bank 4-6.