Removing and Installing Camshafts (Includes Setting Timing)
Removing and installing camshafts (includes setting timing).
Preliminary Work
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. Remove engine.
2. Remove transmission.
3. Secure engine support to the engine/transmission flange with screw sleeves.
4. Secure engine to the assembly support with an engine lift. Get another person to help you do this.
5. Remove rear silencers.
6. Remove cover for camshaft housing.
7. Remove spark plugs. This makes it easier to turn the engine.
Component overview
Component overview for camshafts
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.
1. Check engine position. The first cylinder on the cylinder side to be removed (viewed from the belt side) must be in the overlapping TDC position.
1.1. To do this, turn the engine clockwise at the crankshaft pulley until the correct camshaft position is reached.
1.2. Position of cylinder bank 1-3: the cams on the intake and outlet camshaft of cylinder 1 are facing each other.
Overlapping TDC of cylinder 1
1.3. Position of cylinder bank 4-6: the cams on the intake and outlet camshaft of cylinder 4 point away from each other (each points towards the cylinder head outer wall).
Overlapping TDC of cylinder 4
-1- Outlet camshaft
-2- Intake camshaft
2. Remove chain tensioner (observe the marking).
2.1. Unscrew two M6 x 20 Torx screws on chain tensioner cover and remove cover. Then remove the chain tensioner.
Chain tensioner
3. Remove guide rail for timing chain.
3.1. Unscrew three Torx screws (M6 x 25) on the guide rail and remove the rail.
Guide rail
Information
When loosening or tightening sprockets and camshaft adjustment elements, a second person must counter with the appropriate holding wrench.
4. Loosen outlet sprocket. The timing chain must not be under too much strain during this procedure.
4.1. Loosen M12 cheese head bolt, internal serration -2-; to do this, counter at the sprocket with the special tool holding wrench 9653/1.
4.2. Mark the driver for the cylinder side to avoid problems during installation (different height).
Threaded joint for sprocket and camshaft adjusting element
5. Loosen camshaft adjuster on the intake camshaft. The timing chain must not be under too much strain during this procedure.
5.1. Loosen M12 x 130 central screw by countering at the hexagon piece with a ring wrench (a/f 30) -2-.
Loosening/tightening camshaft actuator
Information
Only remove oil guide housing from the camshaft if the camshaft has to be replaced.
Use a magnetic socket-wrench insert when unscrewing the cylinder screws.
The oil guide housing of cylinder 1-3 and 4-6 differ in height.
Oil guide housing
6. Loosen oil guide housing (do not remove it).
6.1. Heat the three hexagon socket head bolts (M5 x 10, micro-self-locking) with a hot-air gun and screw out bolts.
Threaded joints for oil guide housing
7. Remove camshaft housing.
7.1. Loosen the Torx screws (M6 x 30) on the housings evenly from the inside out. Remove the housings in the specified order.
Camshaft housings
7.2. Lift up the camshaft housings. The housings must not be confused (note the marking).
Lifting up housings
8. Remove thrust bearing cover.
8.1. Unscrew six Torx screws (M6 x 30) and lift the thrust bearing cover up and off (note the marking).
Threaded joints for thrust bearing cover
9. Lift camshafts out.
9.1. Assign camshafts by cylinder bank (e.g. mark with a paint marker) and place them on a clean surface.
Camshaft assignment:
Cylinder bank 1-3: outlet camshaft with lubrication bore for tandem pump and long intake camshaft.
Cylinder bank 4-6: outlet camshaft without bore and short intake camshaft.
10. If necessary, remove exhaust bucket tappets and intake switching tappets and check them for visible wear.
10.1. If you remove them, have a clean surface prepared on which you can write details of each one. Note the installation position of the bucket tappets in the housing.
Example of laying aside bucket tappets
Installing camshafts
Installing oil guide housing
Information
The oil guide housing of cylinder rows 1-3 and 4-6 differ in height.
Oil guide housing
Assembly is only required if the oil guide housing was removed from the camshaft.
1. Fit oil guide housing on the relevant intake camshaft.
1.1. Check the metal rectangular rings for wear. If you find signs of wear, replace them.
1.2. Oil the oil guide housing slightly.
1.3. Push the oil guide housing over the three metal rectangular rings on the intake camshaft. To do this, press the sealing rings together with your hand.
Fitting oil guide housing
Fitted oil guide housing
Installing camshafts
If the bucket tappets and switching tappets were removed:
1. Coat fitting bores for bucket tappets with new engine oil.
1.1. Fit bucket and switching tappets at their original position.
2. Coat camshaft bearing surfaces with new engine oil. When installing the engine for the first time, apply a light coat of Optimol Optipit grease on the bearings (Part No. 000.043.204.17).
Camshaft assignment:
Cylinder bank 1-3: outlet camshaft with lubrication bore for tandem pump and long intake camshaft.
Cylinder bank 4-6: outlet camshaft without bore and short intake camshaft.
3. Fit intake and outlet camshafts for the relevant cylinder bank at the overlap position.
3.1. Position of cylinder bank 1-3: the cams on the intake and outlet camshaft of cylinder 1 are facing each other.
Cam positions with cylinder 1 overlapping
3.2. Position of cylinder bank 4-6: the cams on the intake and outlet camshaft of cylinder 4 point away from each other (each points towards the cylinder head outer wall).
Cam positions with cylinder 4 overlapping
-1- Outlet camshaft
-2- Intake camshaft
4. Place timing chain over the camshaft flanges.
5. Position mounting saddles and thrust bearings (observe the marking).
5.1. Position six housings according to the marking and fit them using 12 M6 x 30 Torx screws.
5.2. Position thrust bearing and fit using six M6 x 30 Torx screws -arrows-.
Threaded joints for thrust bearing cover
6. Fit Torx screws (M6 x 30) evenly to avoid tilting the bearings.
7. Tighten Torx screws evenly to the specified torque in accordance with the specified tightening sequence. - Tightening torque: 13 Nm (9.5 ftlb.).
Camshaft housings
8. Fasten oil guide housing. Place timing chain over the housing.
Threaded joints for oil guide housing
8.1. Screw in three hexagon socket head bolts (M5 x 10) -arrows- with magnetic insert and tighten them. - Tightening torque: 7 Nm (5 ftlb.)
Information
The contact surfaces of the outlet sprockets and camshaft flanges must be completely free of oil and grease.
Observe sprocket markings (left/right).
The drivers for the oil extraction pump/tandem pump differ in height. The driver on cylinder bank 1-3 is higher.
Replace the internal serration screw (M12 x 43) for the sprocket.
Replace the central screw for the camshaft adjusting element (M12 x 130).
Information
Also fit the timing chain when installing the sprockets and camshaft adjusters.
9. Insert camshaft actuator with diamond washer and new central screw (M12 x 130) -1-. Place the timing chain on the splines.
Installing timing chain
9.1. Screw in screw by hand until the camshaft actuator can turn without turning the camshaft.
10. Fit outlet sprocket with timing chain on the camshaft flange and position it using a new internal serration screw (M16 x 43) -2-.
10.1. Screw in screw by hand until the sprocket can turn without turning the camshaft.
Threaded joint for sprocket and camshaft adjusting element
11. Fit guide rail with three Torx screws (M6 x 25) -arrows- and tighten it. Observe the marking -R- or -L-. - Tightening torque: 13 Nm (9.5 ftlb.)
Guide rail
Adjusting camshaft timing
Information
Tighten the screws for the adjustment device only slightly. It must be possible to move the frame easily by hand.
1. Check camshaft position. On the cylinder side to be adjusted, the cams of the first cylinder (viewed from the belt side) must be at the overlap position.
1.1. Overlap of cylinder 1: the cams on the intake and outlet camshaft of cylinder 1 are facing each other.
Cam positions with cylinder 1 overlapping
1.2. Overlap of cylinder 4: the cams on the intake and outlet camshaft of cylinder 4 point away from each other (each points towards the cylinder head outer wall).
Cam positions with cylinder 4 overlapping
-1- Outlet camshaft
-2- Intake camshaft
2.
3. Fit chain tensioner with a new sealing ring. Observe the correct position of the tensioner (top/bottom marking)
3.1. In each case, position and tighten two Torx screws (M6 x 20). - Tightening torque: 10 Nm (7.5 ftlb.)
4. Fit the adjustment device 9661 using two screws on the sealing surface to the valve cover.
4.1. Screw in the screws by hand.
Fitting adjustment device 9661
Setting cylinder side 1-3:
5. Insert the retainer springs 9661/1 into the frame according to the markings and secure them with two fastening screws.
Position of retainer springs for cylinder bank 1-3
6. Adjust camshafts on cylinder side 1-3.
6.1. To do this, use an open-ended wrench (a/f 30) to turn the camshafts at the hexagon until the retaining spring easily enters the slot of the camshaft.
Turning camshafts
6.2. Retainer springs 9661/1 must be secured using the two hexagon-head bolts.
7. Fit dial gauge in order to determine the top piston position correctly.
7.1. A dial gauge is affixed to cylinder 1 on cylinder bank 1-3 using a universal dial gauge holder.
7.2. Extend the probe of the dial gauge until it is certain that the measurement on the piston crown is possible.
Fitting dial gauge.
8. To adjust the timing, the first cylinder of the cylinder side to be adjusted must be positioned at TDC.
8.1. For this purpose, turn the engine at the belt pulley of the crankshaft clockwise until the maximum defection (reversing point) is attained on the dial gauge.
8.2. Remove dial gauge.
9. Pre-tighten the central screw on the camshaft actuator. Counter with a ring wrench (a/f 30) -2- at the hexagon piece while doing this. - Initial tightening: 50 Nm (37 ftlb.)
Loosening/tightening camshaft actuator
10. Pre-tighten the internal serration screw on the outlet sprocket. Counter with a holding wrench 9653/1 while doing this. - Initial tightening: 30 Nm (22 ftlb.)
11. Remove the retainer springs 9661/1.
12. Tighten the central screw on the camshaft actuator. Counter at the hexagon piece with a long ring wrench (a/f 30) while doing this. - Torque angle: 110°±5°
13. Tighten the internal serration screw on the outlet sprocket. Counter with a holding wrench 9653/1 while doing this. - Torque angle: 90°±5°
Setting cylinder side 4-6:
14. Turn the engine a further 360° clockwise at the crankshaft pulley to set cylinder side 4-6.
15. Set cylinder side 4-6 in the same way as cylinder side 1-3.
Fit the adjustment device 9661 on cylinder side 4-6.
Position of retainer springs for cylinder bank 4-6
16. Check the timing. Turn engine on belt pulley of crankshaft clockwise by 720°.
17. Check cam position on the relevant cylinder side in terms of overlapping.
18. Then refit the retainer springs and check the timing on both cylinder sides.
19. Remove the adjustment devices if the timing is correct, otherwise set the timing again.
Subsequent Work
1. Install spark plugs.
2. Install cover for camshaft housing.
3. Fit rear silencers.
4. Loosen engine on the assembly support with an engine lift and remove lifting platform. Get another person to help you do this.
5. Screw off screw sleeves for the engine support on the engine/transmission flange and remove support.
6. Refit transmission.
7. Install engine.