Service Manual
2.
Record measurements taken at top and
bottom
of
piston travel as follows:
A
B.
C.
D.
E.
F.
Measure and record as
“A
the cylinder bore
diameter (parallel to crankshaft) near the top of
cylinder bore.
Measure and record as
“B’
cylinder bore
diameter (parallel to crankshaft) at the bottom of
piston travel.
Measure and record as
“C”
cylinder bore
diameter (perpendicular to crankshaft) near the
top of cylinder bore.
Measure and record as
“D”
cylinder bore
diameter (perpendicular to crankshaft) at the
bottom of piston travel.
Reading
“A”
subtracted from reading
“B”
and
reading
“C”
subtracted from reading
“D”
indi-
cates cylinder taper.
If
cylinder taper exceeds that specified in
DIMENSIONS AND CLEARANCES
rebore and
hone cylinder to the next oversize.
Reading
“A
compared to reading
“C“
and
reading
“B”
compared to reading
“D
indicate
whether
or
not cylinder is out of round.
if
out of
round exceeds that specified in
DIMENSIONS
AND CLEARANCES
the cylinders must be
rebored and honed to the next oversize.
Reboring the Cylinder
Rebore and hone engine whenever cylinder bore
is
worn, damaged, out of round,
or
if
cylinder taper
exceeds specifications.
A
worn cylinder bore should be
resized to the smallest standard oversize diameter at
which
it
will-clean up. The final finish and bore diameters
should then
be
obtained
by
honing. Final bore diameter
should equal the standard diameter added to the
oversize.
If
boring
bar
is operated incorrectly,
it will produce
a
rough cylinder
surface
that
may
not
clean up even when honed. Boring
should
be
done only
by
qualified
service
personnel
who
are
careful
in
their
work.
WEAR
RING
AREA
FIGURE
18.
METHODS
OF
MEASURING
THE
DIAMETER
OF
A
CYLINDER
BORE
After boring to the correct oversize cylinder bore
dimension piston and ring clearance should be
appropriate. There is no need to adjust
or
“fit” pistons
and rings.
When reboring cylinders, take the following pre-
cautions:
1.
Make sure cutting tool is properly ground before
using
it.
2.
Be
sure top of engine block is smooth and deposit
free.
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