3-64
DE347
NOTE: Planing the engine block is not recom-
mended as it will directly affect piston-to-cylinder
head clearance. To determine if the cylinder deck
can be planed, use the following procedure.
A. Determine the maximum cylinder deck varia-
tion (V
d
).
B. Add the deck variation (V
d
) to the piston pro-
trusion (P
p
) determined during removing (V
d
+
P
p
) to determine final piston protrusion (P
pf
).
V
d
+ P
p
= P
pf
.
C. Compare the final piston protrusion (P
pf
) to the
chart to determine if gaskets are available that
would allow planing of the cylinder deck.
Example 1:
P
p
= 0.82 mm (0.032 in.)
V
d
= 0.13 mm (0.005 in.)
0.82 + 0.13 = 0.95 mm (0.037 in.)
P
pf
= 0.95 mm (0.037 in.)
Using the preceding chart, the middle gasket could be
used; therefore, the cylinder deck could be planed suf-
ficiently to be salvaged.
Example 2:
P
p
= 0.82 mm (0.032 in.)
V
d
= 0.30 mm (0.012 in.)
0.82 + 0.30 = 1.12 mm (0.044 in.)
P
pf
= 1.12 mm (0.044 in.)
Using the preceding chart, it can be determined that no
gasket would be available to allow sufficient pis-
ton-to-cylinder head clearance; therefore the engine
block must be replaced.
D. If engine block is not serviceable, it must be
replaced with a new block.
6. Thoroughly clean the engine block using a
non-caustic engine cleaning solution; then rinse
with hot water and dry with compressed air.
7. Using a cylinder bore gauge or suitable snap gauge
and micrometer, measure the cylinder bore at three
locations taking measurements at 45° intervals. If
the cylinder is found to be 72.050 mm (2.836 in.)
or greater at any measurement point, the cylin-
der(s) must be bored. Oversized pistons/rings are
available in 0.50 mm (0.020 in.) and 1.00 mm
(0.039 in.) sizes.
DE369
DE350
8. Using a suitable ridge reamer tool, clean the top of
the cylinder bore; then using a ball hone, hone the
cylinders to produce a 45-55° cross-hatch.
NOTE: To produce the proper 45-55° cross-hatch
pattern, use a low-RPM drill (600 RPM) at the rate
of 25 strokes per minute. Use honing oil or light-
weight petroleum-based oil. Thoroughly clean the
cylinder after honing using soap and hot water.
Dry with compressed air; then immediately apply
engine oil to the cylinder bore. If the bore is
severely scored or out of round, the cylinders must
be bored.
Final Piston
Protrusion (P
pf
)
Gasket Thickness
# of Holes
0.82-0.91 mm
(0.032-0.036 in.)
1.56-1.64 mm
(0.061-0.065 in.)
1
0.92-1.01 mm
(0.036-0.040 in.)
1.66-1.74 mm
(0.065-0.069 in.)
2
1.02-1.10 mm
(0.040-0.043 in.)
1.76-1.84 mm
(0.069-0.072 in.)
3
! WARNING
Always wear safety glasses when using compressed
air.
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