Removing and Installing Valve Tappets of Cylinder Bank 4 - 6

Removing and installing valve tappets - Engine removed








Tools


Removing valve tappets of cylinder bank 4 - 6





1. Remove fixing pin. Turn crankshaft clockwise until the bore 1 OT (top dead centre) in the belt pulley is aligned with the fixing bore on the crankcase. Position or fix with fixing pin (short) of special tool 9595.
2. Check camshaft adjustment at cylinder bank 4 - 6: The groove in the camshaft must face inward toward the crankcase.





View from the belt pulley side
3. Turn engine by 90° on assembly support until cylinder bank 4 - 6 faces upwards.





4. Unscrew chain tensioner of cylinder bank 4 - 6.
5. Remove closure cap from tensioning element (VarioCam). Hexagon-head bolts M6 x 20 (2 ea.).
6. Remove cylinder head cover. Loosen hexagon-head bolts from the outside to the inside.





7. Fit holding-down device for camshafts, special tool 9611. Use auxiliary screws M6 x 45.





8. Detach and remove oil extraction pump at cylinder head 4 - 6 (pulley side).
9. Relieve camshaft tensioning element with tensioning screw, special tool 9632.

Note;
- Screw tensioning screw in only until the chain is slightly relieved.

10. Unscrew three fastening screws (M6 x 95) for tensioning element.
11. Affix auxiliary chain tensioner (screw in by approximately 3 turns). Undo four hexagon-head bolts (M6 x 15) on the chain sprocket. Remove auxiliary chain tensioner again.





12. Remove drive plate. Connect sprocket wheel and chain with a tie wrap (installation position). With a second tie wrap suspend the sprocket wheel and chain to the side under slight tension.
13. Detach two bearing saddles. Lever bearing saddles out of the guide sleeves.
14. Remove holding-down device (special tool 9611) from the camshafts.





15. Carefully lift the complete unit, camshafts with chain and tensioning element out of the cylinder head. The chain must not jump over. The groove or tab of the camshaft position sensor cover must face downward. If the allocation should be uncertain, e.g. chain jumped over, reallocation is necessary. Refer to: Completing camshafts
16. Lift out valve tappets with a magnet.
17. Detach guide for valve tappet. Undo the pan-head screws (15 ea.) from the outside to the inside, and remove the guide.

Installing valve tappets - cylinder bank 4 - 6
1. Check guide for damage. Refer to: Checking guide for valve tappet.
2. Fit guide. Tighten pan-head screws (M6 x 35) from the inside to the outside. Tightening torque 10 Nm (7.5 ft. lbs.)
3. Lightly oil the valve tappet and fit it in the guide.





4. Lay the complete unit, camshafts with chain and tensioning element into the cylinder head. The groove or tab of the camshaft position sensor cover must face downward.





5. Special tool 9611; fit holding-down device for camshafts. Fit auxiliary screws M6 x 45 with washers and tighten to 10 Nm (7.5 ft. lbs.).





6. Check dowel sleeves (4 ea.) of the bearing saddles to ensure that they are properly seated in the cylinder head. Grease bearing surface, fit bearing saddles in correct position and tighten evenly. Tightening torque 10 Nm (7.5 ft. lbs.)
E Bearing saddle for inlet camshaft
A Bearing saddle for exhaust camshaft
7. Fit tensioning element (VarioCam). Tighten 3 M6 x 95 pan-head screws. Tightening torque 10 Nm (7.5 ft. lbs.)
8. Unscrew tensioning screw, special tool 9632, from the tensioning element.





9. Remove tie wrap and fit sprocket wheel with chain on the flange of the exhaust camshaft.
10. Position drive plate or driver star on the sprocket wheel. Fit hexagon-head bolts M6 x 15 (10.9). Tighten hexagon-head bolts by hand only.





11. Fit auxiliary chain tensioner, special tool 9599, on cylinder head 4 - 6.
Fit auxiliary chain tensioner without sealing ring and fasten on the crankcase only hand-tight.
The mechanical auxiliary chain tensioners must be installed with the correct pre-tension when the valve timing is adjusted or checked.
The necessary pre-tension force has been achieved when the measuring pin is flush with the face surface of the pressure screw.
Turn the screw if necessary.
12. Check whether the auxiliary chain tensioners of cylinder bank 1 - 3 and the auxiliary chain tensioner are fitted on the crankcase half.





Chain tensioner on the crankcase





Chain tensioner on cylinder head 1 - 3





13. Remove holding-down device 9611.





14. Prepare cylinder head cover for installation: Clean sealing surface of the cylinder head and cylinder head cover very carefully. Apply a silicone bead to the cylinder head cover. Refer to: Sealing cover for camshaft housing (cylinder head cover).
Carefully place the cylinder head cover in the correct position so that the sealing bead is not damaged. Screw two studs or centering pins into the corners of the cylinder head as centering aids.
Immediately remove silicone material emerging in the area of the camshaft closure cap.

Special Tool Fitting Sequence::

15. Fasten blocking device (special tool 9612) on the cylinder head.





Special tool fitting sequence:

16. Allocate camshafts; to do this, turn the pre-tensioned centre piece accordingly until the sword bolt can be fixed in the bearing bore.





17. Fasten sprocket wheel. Tightening torque 14 Nm (10.5 ft. lbs.)
18. Remove blocking device.
19. Fit camshaft closure caps (3 ea.) dry.
20. Fit closure cap on tensioning element (VarioCam).
Tightening torque 10 Nm (7.5 ft. lbs.)
21. Fit oil supply pump.

Note;
- The oil extraction pumps on the cylinder heads are identical parts. Therefore, the installation position and direction of rotation must be correct.





Installation position of oil extraction pump at cylinder head 4 - 6 (belt pulley side).
The arrow for the direction of rotation or the marking "4 - 6" must face the crankcase.
Fit oil extraction pump. Use new sealing ring and new micro-encapsulated hexagon socket head screws.
Tightening torque 10 Nm (7.5 ft. lbs.)








22. Unscrew auxiliary chain tensioner, put new sealing ring on the original chain tensioner and install.
Tightening torque 80 Nm (59 ft. lbs.)
Allocation of chain tensioners

Installation position of the chain tensioners (engine in installed position)





Chain tensioner on the crankcase





Chain tensioner on cylinder bank 1 - 3





Chain tensioner on cylinder bank 4 - 6

Move camshafts and crankshaft to basic position








1. Turn crankshaft clockwise until the bore 1 OT (top dead centre) in the belt pulley is aligned with the fixing bore on the crankcase. Position or fix with fixing pin (short) of special tool 9595.

Note;
- The basic camshaft setting can be checked only after removal of the camshaft closure caps.

2. Remove camshaft closure caps above the cylinder head oil extraction pumps. The closure cap of cylinder bank 1 - 3 is located on the flywheel side and the closure cap of cylinder bank 4 - 6 is located on the pulley side. Drive awl into centre of the closure cap and lever off the cap.





Drawing shows closure cap of cylinder bank 4 - 6 (pulley side)

3. Check basic camshaft adjustment.

Basic camshaft adjustment of cylinder bank 1 - 3
For adjustment, the groove in the camshaft must face outward toward the cylinder head cover.





View from the flywheel side
If the position of the camshafts is incorrect, remove fixing pin at the pulley and rotate the crankshaft 360° clockwise.

Basic camshaft adjustment of cylinder bank 4 -6
For adjustment, the groove in the camshaft must face inward toward the crankcase.





View from the belt pulley side
If the position of the camshafts is incorrect, remove fixing pin at the pulley and rotate the crankshaft 360° clockwise.