c
Cleaning
After removing pistons, crankshaft, cylinder heads,
etc., inspect block for cracks and extreme wear. If
block
is
still
serviceable,
prepare
it
for
cleaning
as
f
0
Ilows:
1.
Scrape all old gasket material from block.
Remove oil by-pass to allow cleaning solution to
contact inside of oil passages.
2.
Remove grease and scale from cylinder block by
agitating in a bath of commercial cleaning solu-
tion or hot soapy washing solution.
3.
Rinse block in clean hot waterto remove cleaning
solution.
Inspection
When rebuilding the engine, thoroughly inspect
block for any condition that would make it unfit for
further use. This inspection must be made after all
parts have been removed and block has been tho-
roughly cleaned and dried.
1.
Make a thorough check for cracks. Minute cracks
-
may be detected by coating the suspected area
with a mixture of
25
percent kerosene and
75
percent light motor oil. Wipe the part dry and
immediately apply a coating of zinc oxide (white
lead) dissolved in wood alcohol. If cracks are
present, the white coating will become discolored
at the defective area. Always replace a cracked
cylinder block.
2. Inspect all machined surfaces and threaded
holes. Carefully remove any nicks or burrs from
machined surfaces. Clean out tapped holes and
clean up any damaged threads.
3.
Check top of block for flatness with a straight
edge and a feeler gauge.
Cy/inder
Bore
Inspection:
Inspect cylinder bores for
scuffing, scratches, wear, and scoring. If cylinder
bores are scuffed, scratched, scored, or worn, they
must be rebored and honed for the next oversize
piston.
When the appearance of cylinder bores is good and
there are noscuff marks, check cylinder bore for wear
or out of roundess as follows:
1.
Check cylinder bore for taper, out-of-round, and
wear with acylinder bore gauge, telescope gauge
or inside micrometer. These measurements
should be taken at four places, top and bottom of
piston ring travel, parallel and perpendicular to
axis of crankshaft.
2. Record measurements taken at top and bottom of
piston travel as follows (see Figure 9-29).
TOP
END
OF
CYLINDER
RING
AREA
‘WEAR
BOTTOM
OF
RING
TRAVEL
FIGURE
9-29.
METHODS
OF
MEASURE
CT-1090
CYLINDER
BORE DIAMETER
A. Measure and record as
“A”
the cylinder bore
diameter (parallel to crankshaft) near the top
of cylinder bore where greatest amount of
wear occurs.
B.
Also measure and record as
“B”
cylinder bore
diameter (parallel to crankshaft) at the bot-
tom
of
piston travel.
C.
Measure and record as
“C”
cylinder bore
diameter (perpendicular to crankshaft) near
the top of cylinder bore where greatest
amount of wear occurs.
D.
Also measureand record as “D”cylinder bore
diameter (perpendicular to crankshaft) at the
bottom of piston travel.
E.
Reading “K’subtracted from reading“6”and
reading
“C”
subtracted from reading
“D”
indicates cylinder taper.
If cylinder taper exceeds
0.003
inch
(0.08
mm), rebore and hone cylinder to the next
oversize.
9-1
3
Redistribution or publication of this document
by any means, is strictly prohibited.
Redistribution or publication of this document
by any means, is strictly prohibited.
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