Porsche 928 Workshop Manual page 156

928 Ermine. Crankshaft. Pistons
13
a
Checking pistons and cylinder bores - Type 928 GTS ($4 I)
Engine Type M 28.49/50
Repair size Piston dia.
(mm)
Kolbenschmidt
Cyilinder bore
(mm)
Tolerance group
identification
Standard 99,980 100,000 0
99,990 k 0,007 100,010 t 0,005 1
100,000 100,020 2
1 st oversize 100,480 100,500 I 0
100,490 + 0,007 100,510 t 0,005 I 1
100,500 100,520 I 2
Checking the pistons
Measure approx. 50 mm from piston crown.
90 deg. offset to piston pin axis.
Checking the cylinder bores
Measure approx. 50 mm from upper edge of
cylinder bore in transverse direction of
cylinder block.
Prior to measuring, fit crankcase bottom sec-
tion and tighten to specified torque.
Note
It is recommended that the stocks of the relevant piston tolerance group are checked before machin-
ing the cylinders. If necessary, hone to the piston size available.
In some cases, certain tolerance groups may be in short supply.
a
Checking pistons and cylinder bores - Type 928 GTS (5,4 I) 13-24e
Printed in Germany - XXVII, 1991