Fitting Pistons to Cylinders 4 - 6

Removing and installing pistons




Tools




Designations and explanations


Fitting pistons on cylinder bank 4 - 6

Note The crankcase half of cylinder bank 4 - 6 must be fitted before installation of the pistons.

Installation

1. Thoroughly clean sealing surface of the crankcase half of cylinder bank I - 3.





2. Ensure that the profile seals on the oil separator and the two seals on the coolant duct are seated correctly.

3. Apply a uniform bead of silicone approximately 1.5 mm wide to the cleaned sealing surface of the crankcase half of cylinder bank 4 - 6.
Instructions: refer to Disassembling and assembling crankcase halves.

4. Place special tool 9645 on the receiving bore of the oil pump and turn the knob clockwise until the centering mandrel is braced in the crankcase half.





5. Before fitting the crankcase half, have a second person pull the drive chain out of the chain space using a wire.

6. Do not damage the sealing bead when setting the crankcase half in place.





7. Fasten crankcase half. Tightening torque: 13 Nm (10 ft. lbs.) Tightening sequence, refer to Disassembling and assembling crankcase halves.
Remove emerging silicone material.





8. Turn the centering mandrel anti-clockwise and remove. Remove silicone residue.
9. Remove special tool 9613.





10. Fit belt pulley. Screw in fastening screw by hand.
Cylinder bank 4 - 6 faces upward. Bore U6 on the belt pulley must be aligned with the fixing bore on the crankcase. Position or fix with fixing pin (short) of special tool 9595.





Note Fixing of the belt pulley is absolutely necessary in order to ensure precise fitting of the pistons.





11. Align connecting rod of cylinder 6. Insert centering mandrel, special tool 9608, in the assembly bore.





Note The centering mandrel remains in the eye of the connecting rod until the piston contacts the centering mandrel during fitting.

12. Install piston of cylinder 6.





12.1 Check whether the piston pin circlip is present and was fitted correctly (flywheel side).
The piston circlip opening must lie opposite the groove in the piston.





12.2 Before installation, check whether the assembly tube (2) can be moved easily in the piston; remove burr if necessary.





13. Move piston to installation position, position the piston ring restraining strap and insert the piston.

Note Generously coat the piston, cylinder and restraining strap with engine oil before fitting the piston.








14. Use the handle of a hammer to tap the piston into the cylinder while firmly pressing on the edge of the restraining strap. Use protective gloves.

Note The piston must be fitted in the cylinder carefully and with feeling. If the resistance increases, immediately interrupt the assembly process. Reposition the piston ring restraining strap and repeat the assembly operation.





15. Center the piston in the cylinder bore and carefully push it down with the assembly aid (special tool 9698) to the centering mandrel stop.
16. Carefully withdraw the centering mandrel and push the piston down to the stop.





17. Align piston and connecting rod again using the centering mandrel.








18. Push in piston pin as far as it will go using the pressure pin of special tool 9602.

19. Prepare piston pin circlip for fitting on the piston. It is important to pre-fit the circlip on a firm surface. The circlip must be pre-fitted only immediately prior to fitting on the piston pin eye.





19.1 Manually insert the new circlip into the conical part of the assembly sleeve, special tool 9603.








19.2 Place assembly sleeve 9603 onto the assembly tube of special tool 9602. Use assembly aid, special tool 9500/3, to slide the circlip from the conical sleeve into the assembly tube.





19.3 Remove assembly sleeve 9500/3 and visually inspect the correct position of the circlip in the assembly tube.





19.4 Carefully insert the pressure pin (1) of special tool 9602 into the assembly tube (2) until it contacts the piston pin circlip. The circlip can pop out of the assembly tube in the case of improper handling - danger of injury!

20. Carefully insert the complete unit, consisting of assembly tube with pressure pin, into the crankcase assembly bore. Press or position the assembly tube against the crankcase. Turn the assembly tube to move the piston pin circlip to the correct position. The piston circlip opening should lie opposite the groove in the piston for fitting. Mark the assembly tube.

Move the piston pin circlip to the correct installation position by briefly and forcefully striking the palm against the handle of the pressure pin.





Move the piston pin circlip to its installation position by briefly and forcefully striking the palm against the star knob of the pressure pin.








21. Visually inspect correct seating of the piston pin circlip, e.g. with a shop-made electric torch with mirror.





22. Fitting piston in cylinder 5. Advance the crankshaft clockwise until bore U5 on the belt pulley is aligned with the fixing bore on the crankcase. Position or fix fixing pin.

23. Perform the following assembly steps for piston installation in cylinder 5 as described from Step 11 to Step 21. Deviating assembly steps as from Step 24.








24. A spacer sleeve (3) is additionally required when fitting the piston pin circlip in the piston of cylinder 5.





25. Fitting piston in cylinder 4. Advance the crankshaft clockwise until bore U4 on the belt pulley is aligned with the fixing bore on the crankcase. Position or fix with fixing pin.

26. Perform the following assembly steps for piston installation in cylinder 4 as described from Step 11 to Step 21. Deviating assembly steps as from Step 27.








27. Two spacer sleeves (3 + 4) are additionally required when fitting the piston pin circlip in the piston of cylinder 4.





28. After fitting the pistons, fit a screw plug and new sealing ring in the assembly bore. Use a 12 mm hexagon socket wrench insert. Tightening torque: 80 Nm (59 ft. lbs.)








29. Fit guide rails of cylinder bank 1 - 3 (flywheel side); fit guide rails in correct position.








30. Fit guide rails of cylinder bank 4 - 6 (pulley side); fit guide rails in correct position.





31. Fit oil pump with coolant guide housing Assembly instructions: Refer to Engine Lubrication.

32. Fit intermediate shaft flange.
Grease sealing ring in area of intermediate shaft flange. Grease receiver bore in area of the crankcase. Carefully press in the intermediate flange.

Screw in new micro-encapsulated hexagon-head bolts M6 x 20 (3 ea.).

Tightening torque: 10 Nm (7.5 ft. lbs.)





Tighten locknut with the socket wrench, special tool 9110. For this purpose, hold with a slotted screwdriver 7.0 x 1.1 at the slotted threaded pin.
Tightening torque: 10 Nm (7.5 ft. lbs.)

33. Fit belt pulley.

Note Check whether there are foreign objects in the drive belt grooves of the pulley and remove them if necessary.








Tighten hexagon-head bolt using the socket wrench insert 9594; simultaneously hold with retaining device 9593. Tightening torque: 50 Nm (37 ft. lbs.)

Tightening sequence:
Initial tightening 50 Nm (37 ft. lbs.)
Final tightening 1 x 90° turn