Porshe 911 (997). Manual - part 50

Do not interchange the thrust bearings of the inlet and exhaust camshafts during assembly; observe
identification markings.

• 

9. Insert three thrust bearings and one housing -arrows- for the bearing sleeve of the camshafts together with

the guide rail for the timing chain.

Position of housing screws

10. Insert eight housing screws (Torx): six M6 x 35 -1- and two M6 x 40 -2- for camshaft bearing and guide

rail. Tighten screws evenly and just finger-tight.

Adjust timing, cylinder bank 4 - 6

Slot position of camshafts at overlap

11. Align both camshafts. The small circular cut-outs must point upwards -arrows- .

Position of adjusting gauge 9689

12. Using special tool adjusting gauge 9686, fix camshafts (if necessary with the gauge twisted) with

an M8 screw (e.g. hexagon-head bolt M8 x 16). The flat tool face points upwards. Screw in
fastening screw by hand.

13. Screw the housing screws of the inlet and exhaust camshafts and the auxiliary screw of the

adjustment gauge alternately by approx. another 90° until the specified tightening torque is
reached. → Tightening torque: 7.5 ftlb.

Diagnostic system: reading out fault memory and activating systems

Installing camshafts, adjusting timing - engine removed

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14. Insert guide rail screw with a new O-ring and tighten (hexagon socket M6, a/f 5) Grease O-ring

with Optimol MP3. → Tightening torque: 7.5 ftlb.

Chain tensioner, cylinders 4 - 6

15. Fit chain tensioner, side 4 - 6 (hexagon socket a/f 14). Fit chain tensioner with new aluminium

sealing ring and tighten. → Tightening torque: 59 ftlb.

Pulley fixed at TDC marking

Note

Position crankshaft above the pulley or vibration balancer before final adjustment of the timing to the
TDC marking.

• 

16. Turn the crankshaft by means of the pulley or vibration balancer clockwise (running direction of engine

to TDC mark : marking U6 on pulley or vibration balancer coincides with fixing bore in crankcase.
Fix with locating pin 9595/1.

Exhaust camshaft sprocket tightened

17. Insert four Torx screws M6 to sprocket of exhaust camshaft and tighten evenly in diagonally

opposite sequence. → Tightening torque: 10.5 ftlb.

Diagnostic system: reading out fault memory and activating systems

Installing camshafts, adjusting timing - engine removed

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Contact block at the fitting bore of the cylinder head

18. Tighten the central screw of the camshaft adjusting device. Fit special tool retaining tool 9685 on

hexagon of intermediate piece of the central screw. Screw in the central screw gently by hand so that the
loose contact block just touches the fitting bore of the oil suction pump. Fix the hexagon-head bolt to the
contact block.

Tighten central screw of camshaft adjusting device.

Note

Before final tightening (torque angle) of the central screw, the special tool adjusting gauge 9686
must be removed.

• 

19. Tighten the central screw in two stages. Initial tightening to the specified toque. → Initial

tightening: 37 ftlb.

20. Remove special tool adjustment gauge 9686. Undo the M8 screw and remove gauge.

21. Apply final tightening to central screw with torque angle wrench. → Final tightening torque angle:

110 °

Assembly of cylinder bank 1 -3

22. Turn the engine on the assembly support until cylinder bank 1 - 3 stands vertically upwards.

Diagnostic system: reading out fault memory and activating systems

Installing camshafts, adjusting timing - engine removed

359

Pulley fixed at 60° before TDC

23. Turn the crankshaft by means of the pulley or vibration balancer clockwise (running direction of

engine

 further still until the marking U6 on pulley or vibration balancer coincides with fixing

bore in crankcase

 (60° before TDC). Fix with locating pin 9595/1.

24. Oil the bearing surfaces of the camshafts with new engine oil.

Inlet camshaft 1-3 in overlap

25. Insert inlet camshaft 1 - 3. Pull the control chain out of the chain housing of the cylinder head with a

welding wire and position on the toothed ring of the camshaft adjuster. Then insert the camshaft at
overlapping TDC of cylinder 1 (the cams of cylinder 1 point diagonally downwards towards the outside
of the cylinder head -arrow- ).

Position of bearing sleeve for inlet camshaft

Note

Make sure that the bearing sleeve on the inlet camshaft is positioned correctly.

• 

26. The bearing sleeve of the inlet camshaft must be positioned so that the centrally bored blind hole points

vertically upwards -arrow- (the rib of the cylinder head should also be at the centre in relation to the
bearing sleeve). In this position, the dowel pin in the bearing bore of the cylinder head will fit precisely

Diagnostic system: reading out fault memory and activating systems

Installing camshafts, adjusting timing - engine removed

360