93
DE367
25. Using a suitable outside micrometer, measure piston
skirt diameter at a distance of 9 mm (0.350 in.) from
the bottom of the skirt and 90° from the piston pin
axis. Pistons and cylinder measurements must be
within specifications as listed in the following chart.
Class markings are stamped on the cylinder deck.
DE354
DE356B
NOTE: Replacement pistons are only supplied as
class A. Class B and C are reserved for production
engines. Replacement pistons are available over-
sized by 0.50 mm (0.020 in.) and 1.00 mm (0.039 in.)
and are supplied with piston rings.
NOTE: The engine block must be bored in order to
install oversized pistons.
26. Thoroughly clean all components after machining to
insure no filings or metal chips are present. Blow out
all oil galleys with compressed air.
Installing
1. Mount the engine block on a suitable engine stand;
then install the upper main bearing inserts into the
main bearing saddles making sure the oil holes in the
inserts are aligned with the oil galleys in the saddles
and the locating tabs are oriented in the reliefs.
DE376A
2. Install the thrust bearing inserts into the rear main
bearing saddle using a small amount of oil-soluble
grease to hold them in place.
DE628A
3. Install the lower main bearing inserts into the main
bearing caps; then install the thrust bearing inserts
into the rear main bearing cap using oil-soluble
grease to hold in place.
Class Cylinder Diameter
Piston Diameter
Clearance
A
74.990-75.000 mm
(2.9523-2.9527 in.)
74.930-74.940 mm
(2.9499-2.9503 in.)
0.050-0.070 mm
(0.002-0.003 in.)
B
75.000-75.010 mm
(2.9527-2.9531 in.)
74.940-74.950 mm
(2.9503-2.9508 in.)
0.050-0.070 mm
(0.002-0.003 in.)
C
75.010-75.020 mm
(2.9531-2.9535 in.)
74.950-74.960 mm
(2.9508-2.9512 in.)
0.050-0.070 mm
(0.002-0.003 in.)
CAUTION
Do not attempt to use standard rings on oversized pis-
tons or oversized rings on standard pistons. Severe
engine damage will occur.
! WARNING
Always wear safety glasses when using compressed
air.
