Service Manual
2.
Record measurements taken a? top and bottom of
piston travel as follows:
A.
B.
C.
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.
TOP
END
OF
CYLINDER
WEAR
RING
AREA
D.
E.
F.
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 borediameters
should then be obtained by honing. Final bore diameter
should equal the standard diameter added to the
oversize.
Improper boring will
result
in engine
qualified mechanics.
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:
damage. Boring must be done
by
1.
Make sure cutting tool is properly ground before
using it.
2.
Be sure top of engine block is smooth and deposit
free.
FIGURE
17.
METHODS
OF
MEASURING THE DIAMETER
OF
A
CYLINDER BORE
10-1
1