Service Manual
Measuring
Piston Rings:
1.
Install the piston ring in the cylinder bore. Invert
the piston and push the ring to the end of ring
travel, about halfway into the bore, which trues
the ring end gap. Check the gap with a feeler
gauge (Figure
17).
2.
The practice of filing ring ends to increase the
end gap is not recommended.
If
the ring end gap
does not meet specifications, check for the cor-
rect set of rings and the correct bore size.
A
cylinder bore that is
0.001
inch
(0.03
mm) under
size will reduce the end gap
0.003
inch
(0.08
mm).
FIGURE
17.
POSITIONING
OF
PISTON RING
AND
MEASURING
OF
END
GAP
CYLINDER BLOCK
The cylinder block is the main support for all other basic
engine
parts.
Crankshaft and camshaft are supported by
the block, assuring alignment of the crankshaft and
cylinder
bores.
After removing pistons, crankshaft, cylinder heads, etc.,
inspect block for cracks and wear.
If
block is still ser-
viceable, prepare
it
for cleaning as follows:
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 solution
or
hot soapy washing solution.
3.
Rinse block in clean hot water
to
remove cleaning
solution.
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 thoroughly 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.
Cylinder
Bore
Inspection:
Inspect cylinder bores for
scuffing, scratches, wear, and scoring.
If
cylinder bores
are scuffed, scratched, worn,
or
scored, they must be
rebored and honed for the next oversize piston.
When the appearance of cylinder bores is good and
there are no scuff marks, check cylinder bore for wear
or
out
of roundness as follows:
1.
Check cylinder bore for taper, out of round, and
wear with a cylinder bore gauge, telescopic 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 crank-
shaft (Figure
18).
10-10