Porsche 1972 911 Workshop Manual page 28

Spark plug threads
Valves
Valve arrangement
Exhaust valves
Valve springs
Valve timing
Camshafts
Camshaft drive
Valve clearance, cold,
intake
and exhaust
M
1 4 x 1, 25, machined into
cylinder heads
per cylinder
overhead in 'V"
sodium cooled, with
reinforced seat
coil springs per valve
2
OHC, 1 camshaft per cylinder
bank
cast steel, in three plain
bearings in base metal of
camshaft housing
by chain
0.10 mm (0.004 in.)
measured between valve stem
and rocker arm
M
1 4 x 1,25, machined into
cylinder heads
1 intake, 1 exhaust valve
per cylinder
overhead in "V"
sodium cooled, with
reinforced seat
2 coil springs per valve
OHC, camshaft per cylinder
1
bank
cast steel, in three plain
bearings in base metal of
camshaft housing
by chain
0.10 mm (0.004 in.)
measured between valve stem
and rocker arm
M x
1 4
cylinder heads
1 intake, 1 exhaust valve
per cylinder
overhead in 'V"
sodium cooled, with
reinforced seat
coil springs per valve
2
OHC, 1 camshaft per cylinder
bank
cast steel, in three plain
bearings in base metal of
camshaft housing
by chain
0.10 m m (0.004 in.)
measured between valve stem
and rocker arm