FIGURE 29. METHODS OF MEASURING THE DIAMETER OF A CYLINDER
If cylinder taper exceeds 0.005
inch,
rebore
and hone to accomodate the next oversize
piston.
Reading "A" compared to reading "C"
and reading "B" compared to reading "D"
indicates whether or not the cylinder is out of
round.
If the out of round exceeds 0.002
inch,
the cylinders must be rebored and honed for
the next oversize piston. A reboring machine is
used when going to oversize pistons. The
following repair data covers honing to oversize
by use of a hone.
Repair:
1.
A hone can be used to refinish a cylinder.
2.
Anchor the block solidly for either vertical or
horizontal honing. Use either a drill press or
heavy-duty drill which operates at approximately
250 to 450 rpm.
3. Connect drill to hone and start
drill.
Move the
hone up and down in the cylinder approximately
40 cycles per minute. Usually the bottom of the
cylinder must be worked out first because it is
smaller. Then when the cylinder takes a uniform
diameter, move the hone up and down all theway
through the bore. Follow the hone manufacturer's
recommendations for wet or dry honing and
oiling the hone.
4.
Check the diameter of the cylinder regularly
during honing. A dial bore gauge is the easiest
method but a telescoping gauge can be used.
Check the size at six places in the bore: measure
twice at the top, middle and bottom at 90 degree
angles.
5. The Crosshatch formed by the scratching of the
stones should form an angle of 23 degrees. This
can be achieved by moving the hone up and down
in the cylinder about 40 cycles per minute.
6. Clean the cylinder block thoroughly with soap,
waterand clean rags. A clean white rag should not
be soiled on the wall after cleaning is complete.
Do not use a solvent or gasoline since they wash
the oil from the walls but leave the metal particles.
7. Dry the crankcase and coat it with oil.
CRANKSHAFT
Inspect the bearing journals. If they are scored and
cannot be smoothed out by dressing down, replace
the crankshaft.
Whenever making major repairs on the engine,
always inspect the drilled passages of the crankshaft.
Clean them to remove any foreign material and to
assure proper lubrication of the connecting rods.
31
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