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Home >> Porsche >> 2004 >> 911 Carrera Cabriolet (996) F6-3.6L >> Repair and Diagnosis >> Engine, Cooling and Exhaust >> Engine >> Cylinder Block Assembly >> Piston >> Service and Repair >> Part 1

Part 1














Removing and installing pistons














Fitting pistons and connecting rods

Prepare pistons and connecting rods for installation in the crankcase half of cylinders 1 - 3.

Fitting pistons and piston rods in the crankcase half or bearing housing of cylinder bank 1 - 3
Installation





1. Fasten crankcase half, cylinders 1 - 3, in conjunction with mounting elements 9590 to engine holder 9589.





2. Clean bearing housing support surface, particularly in area of oil duct. Check dowel sleeves for correct seating.
3. Installation of the complete bearing housing in the crankcase half, cylinders 1 - 3. As the bearing housing is heavy, it should be installed using a workshop crane.








Carefully and in stages, lower bearing housing with fitted holder 9607 and using a workshop crane towards the dowel sleeves (2 ea.), observing the following points:








1. To aid in guiding, screw two cylinder head screws approximately 3 turns into the bearing housing from below.





2. Just before reaching the final installation position, pull the loosened intermediate-shaft flange out of the housing area and rotate the flange so that the two flange lugs that are spaced closest together face upwards.





3. After lowering, check whether there is sag in the upper chain area or sufficient lever travel exists. Lift the bearing housing and check the chain installation if necessary.
4. Remove two cylinder head screws (guidance aid).





4. For the following assembly procedure - piston installation, cylinders 1, 2 and 3 - the crankcase half and bearing housing unit must be held by at least two screw connections. For this purpose, fasten two original cylinder head screws and plastic spacer sleeves, special tool 9613, from below. Tightening torque 30 Nm (22 ft. lbs.). Use Torx screwdriver insert T50 or T55.
5. Turn crankcase by 180° on the assembly support. Cylinders 1, 2 and 3 face upwards.
6. Fit belt pulley. Screw in fastening screw by hand.





7. Turn crankshaft clockwise until the bore U4 on the belt pulley is aligned with the fixing bore on the crankcase. Position or fix with fixing pin (short) of special tool 9595.





8. Remove preassembled connecting rod with piston of cylinder 1 from the assembly fixture.





9. Align the gaps of the upper piston rings offset by 180°. Make sure that the gap of the second piston ring is aligned with the twist lock.





10. Place piston with connecting rod in installation position.
11. Tighten piston ring restraining strap and fit piston with connecting rod.








Note;
- Generously coat the piston and restraining strap with engine oil before fitting the piston.

12. 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.





13. Centre the piston in the cylinder bore and carefully push it down with the assembly aid (special tool 9598). Use assembly aid with larger diameter and insertion depth.





14. Turn crankcase by 180°. Make sure the bearing shell is correctly seated in the connecting rod. The fixing lugs point to the oil pan.








15. Fit end caps. Lubricate bearing shells. The recesses of the connecting-rod bearing twist lock must face each other.
16. Tightening specification:
Oil thread and contact surface.
1. Initial tightening 20 Nm (15 ft. lbs.)
To facilitate subsequent checks it is recommended that the screw heads be marked with a colored pen after initial tightening.
2. Final tightening 1 x 90° turn
Use 10 mm socket wrench insert (double hexagon).
17. Fitting piston and connecting rod in cylinder 2





Turn crankcase by 180°. Turn crankshaft clockwise until the bore U5 on the belt pulley is aligned with the fixing bore on the crankcase. Position or fix with fixing pin (short) of special tool 9595.
18. Prepare preassembled connecting rod with piston of cylinder 2 for installation. Perform the following assembly steps as described from Step 8 to Step 16.





19. Fitting piston and connecting rod in cylinder 3 Rotate crankshaft clockwise until bore U6 on the belt pulley is aligned with the fixing bore on the crankcase. Position or fix with fixing pin (short) of special tool 9595.
20. Prepare preassembled connecting rod with piston of cylinder 3 for installation. Perform the following assembly steps as described from Step 8 to Step 16.

Note;
- Leave crankshaft at position U6 after fitting the piston and connecting rod in cylinder 3. This position is necessary for subsequent fitting of the piston of cylinder 6.
21. Remove belt pulley.

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 (9.5 ft. lbs.). 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.
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