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
16).
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).
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.
Cleaning
After removing pistons, crankshaft, cylinder heads, etc..
inspect block for cracks and wear.
If
block
is
still
serviceable, 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
FIGURE
16.
POSITIONING OF PISTON RING
AND MEASURING OF END GAP
or hot soapy washing solution.
3.
Rinse block in clean hot water
to
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 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 hone3 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:
Connecting Rod Inspection:
1.
Check cylinder bore for taper, out of round, and
Replace connecting rod bolts and nuts that have
wear with a cylinder bore gauge, telescopic gauge.
damaged threads. Replace connecting rods that
or inside micrometer. These measurements should
have deep nicks, signs of fractures, scored bores, or
be taken at four places: top and bottom of piston ring
bores with dimensions which exceed that specified
travel, parallel and perpendicular
to
axis of crank-
in
DIMENSIONS AND CLEARANCES.
shaft (Figure
17).
10-10