Fitting Pistons to Cylinders 4 - 6

Removing and installing pistons - Boxster S




Engine type M96/21







Tools

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 1 - 3.








2. Ensure that the profile seals on the oil guide and the two seals left and right of the coolant duct are seated correctly.

3. Place centering mandrel, special tool 9645, on the take-up bore of the oil pump and turn the star knob clockwise until the centering mandrel is braced in the crankcase half (oil pressure builds up in centering mandrel).





4. 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.

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

6. Carefully set the crankcase half in place so that the sealing bead is not damaged.

7. Fasten crankcase half. Tightening torque 13 Nm (10 ft. lbs.). Tightening sequence.





Immediately remove silicone material emerging in the area of the oil pan sealing surface.





8. Relieve centering mandrel. Turn star knob anti-clockwise (oil pressure drops) and remove centering mandrel. Remove silicone residue.





9. Fasten engine holder, special tool 9589, to the crankcase half of cylinder 4 - 6 (3rd fastening point).





10. Remove plastic spacer sleeves, special tool 9613.

11. 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.





12. Unscrew plug for piston pin assembly bore. Use a 12 mm hexagon socket wrench insert.





13. Fasten centering aid, special tool 9602/2, with two countersunk screws with crosshead (M6 x 20) on the crankcase.








14. 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.

15. Install piston of cylinder 6.





15.1 Check whether the piston pin circlip is present and was fitted correctly (flywheel side).









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












16. Align the gaps of the piston rings offset by 120°. Position piston ring clamp and fit piston.

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

17. Use the handle of a hammer to tap the piston into the cylinder while firmly pressing on the edge of the clamp. 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 clamp and repeat the assembly operation.





18. Center the piston in the cylinder bore and carefully push it down with the assembly aid (special tool 9598) to the centering mandrel stop.

19. Carefully withdraw the centering mandrel and push the piston down to the stop.





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








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

22. 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.





22.1 Manually insert the new circlip into the conical part of the assembly sleeve, special tool 9603/1.








22.2 Place assembly sleeve 9603/1 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.

22.3 Remove assembly sleeve 9603/1 and visually inspect the correct position of the circlip in the assembly tube.





Caution! Danger of injury if circlip springs out!

> Check position of the circlip only by visual inspection of the assembly tube from the side.





23. Push assembly tube through the centering piece into the crankcase assembly bore with the circlip fitted.





24. Carefully and gently insert the pressure pin until it contacts the piston pin circlip.





Note: When inserting the pressure pin, the plastic ring on the pressure pin may touch the belt pulley, Either rework the plastic ring or remove the belt pulley briefly.





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








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





27. 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 with fixing pin.

28. Perform the following assembly steps for piston installation in cylinder 5 as described from Step 14 to Step 26.








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





29. 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.

30. Perform the following assembly steps for piston installation in cylinder 4 as described from Step 14 to Step 26.








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





32. Remove centering aid 9602/2.





33. Visually inspect correct seating of the piston pin circlip on the piston of cylinder 4.

Note If the piston, piston pin or piston pin circlip are incorrectly assembled, the corresponding piston can be pulled out of the cylinder as follows.





Degrease center of piston crown. Coat suitable plastic mandrel with instant adhesive. Allow the adhesive to cure. Pull out piston. Remove plastic mandrel immediately.





34. 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.).








35. Fit guide rail and tensioning rail of cylinder bank 1 - 3 (flywheel side); fit guide rails in correct position.








36. Fit guide rails and tensioning rails of cylinder bank 4 - 6 (flywheel side); fit guide rails in correct position.





37. Fit oil pump with coolant guide housing Assembly instructions: refer to Engine Lubrication.

38. Fit intermediate shaft flange.
Grease sealing ring in area of intermediate shaft flange. Grease take-up 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 7.9 x 1.1 at the slotted threaded pin.
Tightening torque 11 Nm (8 ft. lbs.).

39. Fit belt pulley.

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

Tightening sequence:
Initial tightening








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

Final tightening: 1 x 90° turn