Pistons And Cylinders; Piston Ring End Gap - Porsche 911 TURBO - 1989 Workshop Manual

Engine-crankshaft and moving parts
CHECKING PISTONS AND CYLINDERS
Cylinders
Dl = Measuring point for wear and ovality
30 mm below upper edge of cylinder
The cylinder is worn if the measurement is
0.08 mm more than the size at installation.
Measurements are made in directions a and
b to check ovality. The amount of deviation
between a and b should not exceed 0.04 mm.
D2 = Measuring point for piston ring end gap
b _I
I
Rings slid in at height of cylinder base gasket.
Pistons
D = Measuring point for wear
At lower edge of piston pin bore.
~).:-
--
0
-
Caution!
Replace piston and cylinder if clearance
exceeds O.15mm.
PISTON RING END GAP
Piston Ring
End Gap in mm
(new)
End Gap in mm
(wear limjt)
0.15 -0.3
0.8
0.15 -0.3
1.0
Compression ring,
I and II
Oil scraper ring,
III
(see measuring point "D2")
PISTON RING SIDE CLEARANCE
Side Clearance
in mm (wear limit)
0.2
0.2
0.1
Side Clearance
in mm (new)
Piston Ring
Compression ring. I
Compression ring. II
Oil scraper ring. III
0.070 -
0.040 -
0.020 -
13-2 Checking Pistons and Cylinders
IV. 1981
Printed in Germany