Porsche 911 GT3 Cup 2008 Technical Handbook page 12

Valve timing
Adjusting the valve timing on the GT3 Cup engine model
2008. Camshaft opening lead/closing lag (105° / 115°)
with special tool 000 721 996 10 and accessories.
Description:
Set cylinder number 1 to TDC using a dial gauge indicator
Fit degree wheel 996 450 131 00
Fit the camshaft 1 - 3 at the TDC exhaust / inlet valve
overlap and fix the inlet and exhaust valves with the special tool
000 721 966 10 with inlet special tool
exhaust special tool 000 721
Mount the chain tensioning tool 00072194010.
Tighten camshaft wheels to approximately 30 Nm torque.
Remove the special tool from the camshaft slits.
Rotate the crankshaft 360°
Fit the camshaft 4 - 6 at TDC exhaust / inlet valve overlap
and fix the inlet and exhaust valves with the special tool
00072196610 with inlet special tool 9964501*****, and
exhaust special tool 000721*****.
Tighten camshaft wheel to approximately 30 Nm.
Remove the special tool from the camshaft slits.
Set engine to Cyl 1 TDC exhaust / inlet valve overlap
Rotate the engine three turns, and then pretension the chain
tension tool to the marks.
Inlet valve diameter
Inlet valve lift
Exhaust valve
Exhaust valve lift
Maximum inlet valve lift
Maximum exhaust valve lift
996 450 *****, and
*****.
7
41 mm
12.5 mm
35.5 mm
11.1mm
105° after TDC
115° before TDC