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Removing Camshafts - Engine Removed



Removing camshafts - engine removed (as of MY 02)





Engine type M 96 / 03

Caution
When working on the engine, absolute cleanliness is essential! An engine cover should be used on the engine assembly support. Lay removed engine parts on a clean base and cover them without fail. Even the smallest particles of dirt can block up oil bores.

Removing camshafts, cylinder bank 1 - 3

1. Remove the shield (1). Unscrew 2 hexagon-head bolts M6x16.

Pull out the shield to the belt pulley side.





2. Remove holder for main muffler (2). Pull off the electrical plug of ignition coil cyl. 2 and the 2 electrical plugs of the magnetic hydraulic valves. Unscrew 4 hexagon-head bolts: top 2 M8x30, bottom 2 M8x25, then pull out the holder towards the clutch side.
3. Remove 3 ignition coils. Unscrew 6 hexagon socket head bolts M6x25 and pull the ignition coils out from the spark-plug recess.
4. Remove the oil extraction pump and the brown closure cap [diameter] 45 mm (clutch side). Unscrew the 4 hexagon-head bolts M6x20 on the oil extraction pump and remove the pump carefully (do not damage the fitting bore). Press a screwdriver into the center of the piercing point of the closure cap and lever off the cover.





5. Remove the 2 green closure caps (belt pulley side). Press a small screwdriver into the center of the piercing point of the closure cap and lever off the cover.
6. Turn the engine clockwise at the belt pulley of the crankshaft to the overlapping TDC of cylinder 1. Fix with the short fixing pin as of mod. 98 9595/1. At this point, the smaller circular cutouts on the cut grooves of the inlet and exhaust camshafts on cylinder 1 must point towards the cylinder head cover (check with adjustment gauge 9686). If this is not the case, turn the engine through another 360° as described above.








Position of the camshafts in overlapping TDC of cylinders 1 or 4

Information
- Before disassembling the cylinder head cover, it is essential to unscrew the central screw on the camshaft adjustment device.

7. Unscrew the central screw on the camshaft adjustment device. Position the 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 extraction pump; if necessary, position the contact block by undoing and tightening the hexagon-head bolt M8. If the special tool can not be positioned on the hexagon of the adapter in this way, the engine must be turned further in the direction of rotation at the belt 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.





8. Unscrew the 4 hexagon-head bolts M6x16 on the chain sprocket of the exhaust camshaft. Do not remove the chain sprocket.
9. Remove 2 holders and 2 covers for the magnetic hydraulic valves. Unscrew 4 hexagon socket head bolts M6x20, disconnect the connection cable for the hydraulic valves from the sheetmetal bracket and remove the holders. Pull off 2 covers for the hydraulic valves. The valves on side 1-3 can remain connected.

Caution
When levering off the cylinder head cover, the cast lugs may break.

10. Remove cylinder head cover.
11. Turn the engine at the assembly support so that the cylinder bank 1-3 stands vertically upwards.
12. Remove the chain tensioner, side 1-3. Hexagon a/f 30.





13. Remove the chain sprocket of the exhaust camshaft 1-3. Lift control chain off the chain sprocket and remove the chain sprocket. Lay the control chain on the mounting tab for the chain sprocket.
14. Remove the 4 camshaft thrust bearings and the guide rail. Unscrew the 8 hexagon socket head bolts, 6 M6x35, 2 M6x40. Lift the thrust bearing and the guide rail carefully off the bearing surfaces or the control chain.
15. Remove the camshafts. Remove the exhaust camshaft 1-3, lift the control chain off the camshaft adjuster of the inlet camshaft 1-3 and remove the camshaft. Lay the control chain in the chain housing in the cylinder head.





16. Remove the flat-based tappets. Pull the flat-based tappets upwards out of the camshaft housing. To avoid confusing the individual flat-based tappets, lay them on a prepared sheet of paper and cover, because of the risk of soiling.

Caution
Do not confuse the flat-base tappets. The flat-base tappets have been run in the fitting bores in the housing. Therefore they must not be interchanged or soiled.

Removing camshafts, cylinder bank 4 - 6

1. Pull the 2 cable plugs off the oil temperature switch.
2. Remove the shield: unscrew 2 hexagon-head bolts M6x16. Pull out the shield to the clutch side.
3. Remove holder for the main muffler: pull off the electrical plug of ignition coil cyl. 5 and the 2 electrical plugs of the magnetic hydraulic valves. Unscrew 4 hexagon-head bolts: top 2 M8x30, bottom 2 M8x25, then pull out the holder towards the belt pulley side.
4. Remove 3 ignition coils: unscrew 6 hexagon socket head bolts M6x25 and pull the ignition coils out from the spark-plug recess.





5. Remove the oil extraction pump and the brown closure cap [diameter] 45 mm (belt pulley side). Unscrew the 4 hexagon-head bolts M6x20 on the oil extraction pump and remove the pump carefully (do not damage the fitting bore). Push a small screwdriver into the center of the closure cap and lever off the cover.
6. Remove the 2 green closure caps (clutch side). Press a small screwdriver into the center of the piercing point of the closure cap and lever off the cover.
7. Turn the engine clockwise at the belt pulley of the crankshaft to the overlapping TDC of cylinder 4. Fix with the short fixing pin as of mod. 98 9595/1. At this point, the smaller circular cutouts on the cut grooves of the inlet and exhaust camshafts on cylinder 1 must point towards the cylinder head cover (check with adjustment gauge 9686). If this is not the case, turn the engine through another 360° as described above.








Position of the camshafts in overlapping TDC of cylinders 1 or 4

Information
- Before disassembling the cylinder head cover, it is essential to unscrew the central screw on the camshaft adjustment device.

8. Unscrew the central screw on the camshaft adjustment device.

Position the retaining tool 9685 on the hexagon of the adapter and place the contact block of the tool on the fitting bore of the cylinder head cover for the oil extraction pump; if necessary, position the contact block by undoing and tightening the hexagon-head bolt. If the special tool can not be positioned in this way, the engine must be turned further in the direction of rotation at the belt pulley of the crankshaft until the contact block comes into contact with the cylinder head cover. Unscrew the central screw.





9. Unscrew the 4 hexagon-head bolts M6x16 on the chain sprocket of the exhaust camshaft. Do not remove the chain sprocket.
10. Remove 2 holders and 2 covers for the magnetic hydraulic valves: unscrew 4 hexagon socket head bolts M6x20, disconnect the connection cable for the hydraulic valves from the sheetmetal bracket and remove the holders. Pull off 2 covers for the hydraulic valves.
11. Remove 2 magnetic hydraulic valves (camshaft and valve lift adjustment). Pull both valves carefully out of the bores. This removal is necessary, because otherwise the exhaust manifold would have to be removed before removing the cylinder head cover.

Pay attention to cleanliness without fail!

12. Remove the ground strap from the cylinder head. Unscrew 1 hexagon-head bolt M8x20.

Caution
When levering off the cylinder head cover, the cast lugs may break.

13. Remove the cylinder head cover.
14. Turn the engine at the assembly support so that the cylinder bank 4-6 stands vertically upwards.
15. Remove the chain tensioner, side 4-6. Hexagon socket a/f 14. Prerequisite: servo-tank, air-conditioning compressor and holder for the air-conditioning compressor are removed.





16. Unscrew the guide rail screw of cylinder bank 4-6 (belt pulley side). Hexagon socket a/f 6.
17. Remove the chain sprocket of the exhaust camshaft 4-6. Lift control chain off the chain sprocket and remove the chain sprocket. Lay the control chain on the mounting tab for the chain sprocket.
18. Remove the 4 camshaft bearings and the guide rail. Unscrew the 8 hexagon socket head bolts, 6 M6x35, 2 M6x40.
19. Remove the camshafts. Remove the exhaust camshaft 4-6, lift the control chain off the camshaft adjuster of the inlet camshaft 4-6 and remove the camshaft. Lay the control chain in the chain housing in the cylinder head.





Figure shows cylinder side 1-3

20. Remove the flat-based tappets. Pull the flat-based tappets upwards out of the camshaft housing. To avoid confusing the individual flat-based tappets, lay them on a prepared sheet of paper (see illustration) and cover, because of the risk of soiling.

Caution
Do not confuse the flat-base tappets. The flat-base tappets have been run in the fitting bores in the housing. Therefore they must not be interchanged or soiled.
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