Checking Piston And Cylinder Bore - Porsche 928 Workshop Manual

928 Engine, Crenkshafl. Pistons
13
Checking pistons and cylinder bores
I
62
Repair size Piston dia. Piston dia.
(mm) (mm)
Mahle Kolbenschmidt
Cylinder bore
(mm)
Tolerance group
identification
Standard 94.960 94.964 95.000 0
94.970 94.974 r 0.007 95.010 h 0.005 1
94.980
94.984 95.020 2
1 st oversize 95.460
95.464 95.500 0 KD 1
95.470
95.474 +0.007 95.510 -co.005 1 KD 1
95.480
95.484 95.520 2 KD 1
Checking the pistons
Measure approx. 62 mm from piston crown,
90 deg. offset to piston pin axis.
Checking the cylinder bores
Measure approx. 62 mm from upper edge of
cylinder bore in transverse direction of
cylinder block.
Prior to measuring, fii 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.
Checking pistons and cylinder bores
Printed In Gsmany - XXVII, ,991
13-23