Service Manual

3.
4.
Clean base of boring bar before bar is set up. Deglazing Cylinder Bores
Deposits under boring bar will cause it to tilt and the
Deglaze the cylinder bores
if there are no scuff marks
cylinder
will be distorted after boring.
and no wear
or out of round beyond specifications
Make an initial rough cut, followed by a finish cut.
before installing new rings. Deglazing gives a fine finish,
but does not enlarge cylinder diameter,
so the original
Then hone cylinder bore to the specified oversize. pistons with new rings may still be used.
The reason for dealazing a cylinder is to provide cavities
Honing Cylinders (Using Precision Hones) to hold oil during piston ring break-in.
Refer to hone manufacturer's recommended grit size to
produce specified surface finish of
20 to 40 RMS. Too 1. Wipe cylinder bores with a clean cloth which has
rough of a finish
will wear out the rings and too smooth been dipped in clean, light engine oil.
of a-finish can retard piston ring seating.
2. Use a brush type deglazing tool with coated bristle
1.
2.
3.
4.
5.
6.
7.
8.
Position block solidly for either vertical or horizontal tips to produce a crosshatch pattern in the cylinder
honing. Use either
a drill press or heavy-duty drill bore.
which operates at approximately
250 to 450 rpm.
3. Use a slow speed drill to drive the deglazing tool.
Follow hone manufacturer's instructions for the use Move deglazing tool up and down in cylinder
(10 to
of oil
or lubricant on stones. Do not use lubricants 12 complete strokes) rapidly enough to obtain a
with a dry hone. crosshatch pattern (Figure 19).
Insert hone in bore and adjust stones to fit snugly to
the narrowest section. When adjusted correctly, the
hone should not shake
or chatter in cylinder bore,
but
will drag freely up and down when hone is not
running.
Connect drill to hone and start drill.
Feel out bore for
high
spots, which cause an increased drag on
stones. Move hone up and down in bore with short
overlapping strokes about
40 times per minute.
Usually bottom of cylinder must be worked out first
because it is smaller.
As cylinder takes a uniform
diameter, move hone up and down all the way
through cylinder
bore.
Check diameter of the cylinder regularly during
honing.
A dial bore gauge is the easiest method but
a telescoping gauge can be used. Check size at six
places in bore: measure twice at top, middle and
bottom at 90-degree angles.
Crosshatch formed by the stones should form an
included angle of 23 degrees. This can be achieved
by moving the rotating hone
(250 to 450 rpm) up and
down in cylinder bore about
40 times per minute.
Clean cylinder bores thoroughly with soap, water
and clean rags.
A clean white rag should not
become soiled on wall after cleaning is complete.
Do not use a solvent or gasoline since they wash oil
from the walls but leave the metal particles.
Dry crankcase and coat it with oil.
PRODUCECROSSHATCHSCRATCHES AVOID THIS FINISH
FOR FAST RING SEATING
FIGURE 19. CROSSHATCHING
Never use gasoline or commer-
cial cleaners
to clean cylinder
bores after deglazing or honing. These solvents
will not remove abrasives from
the walls. Abra-
sives not removed
from engine will rapidly wear
rings, cylinder walls, and bearing surfaces of all
lubricated parts.
4. Clean cylinder bore thoroughly with soap, water
and clean rags. Continue cleaning until a clean
white rag shows nodiscoloring when wiped through
cylinder 'bore.
10-12