Removing and Installing Camshafts - Engine Removed
Removing And Installing Camshafts - Engine Removed
Tools
Item A - D:
Component Overview And Tightening Torques
Removing Camshafts
The following preliminary work must be carried out:
- Remove engine.
- Remove rear muffler.
- Remove the oil container.
- Remove generator.
- Remove coolant guide housing.
1. Cylinder bank 1 - 3: Undo fuel collection pipe with injection valves and remove holder for turbochargers.
2. Cylinder bank 4 - 6: Undo holder for turbochargers and remove bypass flap control box on turbocharger.
3. Remove ignition coil. Remove cable plug of the ignition coils, unscrew 2 cylinder screws (hexagon socket) M6 x 25 of each and pull ignition coils out of spark-plug recess.
4. Remove 2 closure caps (green, plastic) between camshaft housing cover and cylinder head (clutch side). To do so, puncture the closure cap in the middle and lever out using a small slotted screwdriver.
5. Remove oil extraction pump and closure cap. The oil extraction pump flange must be held with a wrench when the oil line on the pump is loosened. Subsequently unscrew the three fastening screws of the oil extraction pump and the three fastening screws of the closure cap, then lever off the two components.
6. Remove solenoid hydraulic valve for valve lift adjustment. To do so, remove plug, unscrew both hexagon-head bolts M6 x 25 and remove with the holder. Subsequently remove the valve.
7. Remove camshaft housing cover. Unscrew the 15 hexagon - head bolts M6 and remove the camshaft housing cover. If this is stuck, it can be loosened by gently tapping with a plastic hammer.
8. Check engine position. The cylinder side which is to be worked on must be positioned to overlapping TDG so that the camshaft can be removed without tension. For cylinder bank 1 - 3, this means: the cams of the exhaust and inlet shaft of cylinder 1 point towards each other -Figure 8.1-, for cylinder bank 4 - 6: the cams of the exhaust and inlet camshaft of cylinder 4 point away from each other (each points towards the cylinder head outer wall) -Figure 8.2-.
Figure 8.1: Overlapping TDC of cylinder 1
-1- Exhaust camshaft
-2- Inlet camshaft
Figure 8.2: Overlapping TDC of cylinder 4
-2- Inlet camshaft
-1- Exhaust camshaft
9. Remove chain tensioner. To do this, unscrew the two fastening screws of the chain tensioner cover and remove the cover. Then remove the chain tensioner.
10. Remove guide rail for timing chain. Remove the three fastening screws on the short guide rail between the camshaft sprockets and remove the guide rail.
11. Remove camshaft sprockets. The timing chain must not be loaded when the screw connection of the camshaft sprockets is loosened. To remove the sprocket wheels, the actuating element of the inlet camshaft must be countered using special tool holding wrench No. 9653, and the sprocket wheel of the exhaust camshaft must be countered using special tool holding wrench No. 9653/1.
NOTE:
- Only remove oil guide housing from the camshaft if the camshaft has to be replaced
- The pan-head screws of the oil guide housing can fall into the crankcase when unscrewing, the use of a solenoid socket wrench insert is therefore recommended.
- The oil guide housing of cylinder 1 - 3 and 4 - 6 differ in height.
12. Remove oil guide housing. Heat the three hexagon socket head bolts using a hot-air gun, unscrew and remove the housing. The fastening screws are microencapsulated and therefore must be replaced.
13. Remove camshaft bearing cap. To do so, uniformly unscrew the hexagon-head bolts of the relevant bearing covers from the inside. Remove the bearing covers in the specified order.
14. Remove camshaft bearing covers. Lift the bearing covers up and off. The bearing covers must not be confused.
15. Remove thrust bearing cover. Unscrew the hexagon-head bolts and remove the thrust bearing cover up and off.
16. Lift camshafts up and out.
Installing Camshafts
NOTE: The oil guide housing of cylinder banks 1 - 3 and 4 - 6 differ in height.
Comparative view of oil guide housing of cylinder banks 1-3 and 4-6
The following assembly is only required if the oil guide housing has been disconnected from the camshaft when removing.
1. Mount the oil guide housing. Fit the oil guide housing above the three sealing rings of the inlet camshaft. The oil guide housing should be lightly oiled for this purpose. Press the sealing rings together by hand and push the oil guide housing over them.
Prefitted oil guide housing
2. Move engine to TDC. Turn engine on the belt pulley of the crankshaft clockwise until the TDC mark on the belt pulley (crankshaft side of belt pulley) is aligned with the cast lug on the crankshaft housing.
NOTE: The camshafts are allocated via the identification on the rotor cover. The last three digits indicate the cylinder bank in which the respective camshaft is installed.
Position of camshaft designation
WARNING: Risk of damage:
- The bearing locations must not be oiled. Only grease is permissible.
3. Insert camshafts. The bearing locations of the camshafts must be lightly greased before installation. Place the timing chain over the camshafts when inserting the camshafts.
4. Position camshafts. It must be ensured that the camshafts are correctly positioned in the bearing locations. The camshafts must be turned such that the cams of the first cylinder of the bank are located at overlapping TDC. This means that the cams of the inlet and exhaust shaft of the first cylinder point towards each other -Figure 4.1-, the cams of the fourth cylinder point away from each other -Figure 4.2-.
Figure 4.1: Position of the camshafts on overlapping of cylinder 1
-1- Exhaust camshaft
-2- Inlet camshaft
Figure 4.2: Position of the camshafts on overlapping of cylinder 4
-2- Inlet camshaft
-1- Exhaust camshaft
5. Fit bearing cover. Fit the six small bearing covers so that the bearing location numbers on the camshaft housing and on the bearing location face each other. Make sure that the matching numbers on the bearing covers and on the camshaft housing are identical. Position the hexagon-head bolts M6 x 30.
6. Fit thrust bearing cover. Place the large thrust bearing cover onto both camshafts and tighten the hexagon-head bolts M6 x 30 slightly.
7. Tighten bearing cover. Tighten the hexagon-head bolts M6 x 30 of the bearing cover uniformly to tightening torque in the specified sequence.
Tightening torque of the bearing cover screws (10.9) 13 Nm (10 ftlb.)
8. Tighten oil guide housing. Replace the three pan-head screws MS x 10 (microencapsulated) and tighten to tightening torque.
Tightening torque of MS pan-head screws (8.8) 7 Nm (5 ftlb.)
9. Tighten the hexagon-head bolts M6 x 30 for the thrust bearing cover to tightening torque.
Tightening torque of the thrust bearing screws M6 (10.9) 13 Nm (10 ftlb.)
NOTE:
- The camshaft adjusting elements must be positioned to the left- hand stop. Use special tool holding wrench No. 9653
- The hexagon-head bolts M12 for the actuating element of the inlet camshaft is to be replaced
10. Place camshaft adjusting element onto inlet camshaft. Lay the timing chain onto the chain sprocket of the camshaft adjusting element and place the adjusting element onto the inlet camshaft. Tighten the new hexagon-head screw M12 x 120 by hand. Turn the camshaft adjusting element to the left stop using special tool holding wrench No. 9653.
New chain sprockets for the exhaust camshafts (left and right part) have been in use as of May 2001. The identical chain sprocket remains an original Porsche part - observe part numbers
Identification of the sprocket wheels
- Left wheel with coating and part number (identification "left" on rear side)
- Right wheel with part number and identification "right" (coating on rear side)
NOTE:
- The contact surfaces of the sprocket wheels and camshaft flange (exhaust side) must be completely free of oil and grease
- The coated surface points towards the camshaft flange
- The drive plates for the oil extraction pumps differ in height. The drive plate on cylinder bank 1 - 3 is higher
- The internal serration screw M12 must be replaced
11. Fit exhaust camshaft wheel. Clean mounting surface of the sprocket and of the exhaust camshaft and remove all oil and grease. The inscription "left" must be visible for cylinder bank 1 - 3, and "right" must be visible for cylinder bank 4 - 6. Push on the sprocket. Push on the drive plate for the oil extraction pump and tighten the new internal-serration screw by hand. Observe height of drive plates of cylinder banks 1 - 3 and 4 - 6
12. Mount the guide rail between the sprocket wheels. Tighten the three M6 x 25 hexagon-head bolts with the correct tightening torque.
Tightening torque of the hexagon-head bolts M6 (10.9) 13 Nm (10 ftlb.)
13. Set the timing.
NOTE: The following work can be carried out only after the timing has been adjusted
14. Reinstall chain tensioner. Insert the chain tensioner into the chain housing in accordance with its identification, then fit the chain tensioner cover with a new seal. Tighten the hexagon-head bolts M6 to 10 Nm (7.5 ftlb.).
15. Clean sealing surface for the camshaft housing cover.
16. Install camshaft housing cover. Apply a silicone bead of a maximum 1.5 mm -Figure- (drying time of sealant approx. 5 mm). Put on the camshaft housing cover and tighten the 15 fastening screws from the inside to tightening torque.
Tightening torque of the hexagon-head bolt M6 (8.8) 10 Nm (7.5 ftlb.)
17. Install solenoid hydraulic valve for valve lift adjustment. Put on holder with both hexagon-head bolts M6 x 25 and tighten the screws with tightening torque.
Tightening torque of the hexagon-head bolt M6 (8.8) 10 Nm (7.5 ftlb.)
18. Fit the closure cap and the oil extraction pump with new 0- rings. Tighten the hexagon-head bolts: 3 M6 x 20 for the closure cap and 3 M6 x 35 for the oil extraction pump to tightening torque.
Tightening torque of the hexagon-head bolt M6 (8.8) 10 Nm (7.5 ftlb.)
19. Fit four new closure caps (green) for camshaft housing cover in dry state.