TM 5-3895-359-14&P
Inspect Cylinder Block
After cleaning and pressure testing, inspect the cylinder
block.
Since most of the engine cooling is accomplished by
heat transfer through the cylinder liners to the water
jacket, a good liner-to-block contact must exist when the
engine is operating. Whenever the cylinder liners are
removed from an engine, the block bores must be
inspected.
NOTE: Before attempting to check the
block bores, hone them throughout their
entire length until about 75% of the area
above the ports has been "cleaned-up"
1. Hone the block bores as follows:
a. Use a hone in which the cutting radius of
the stones can be set in a fixed position to
remove irregularities in the bore rather
than following the irregularities as with a
spring-loaded hone. Clean the stones
frequently with a wire brush to prevent
stone loading.
Follow the hone
manufacturer's instructions regarding the
use of oil or kerosene on the stones. Do
not use such cutting agents with a dry
hone. Use 120 grit stones J 5902-14.
b. Insert the hone in the bore (Fig. 10) and
adjust the stones snugly to the narrowest
section. When correctly adjusted, the
hone will not shake in the bore. but will
Fig. 12. Checking Bore of Cylinder Block
drag freely up and down when the hone is
not running.
the water jacket and blow out all of the passages in the
c. Start the hone and "feel out" the bore for
block with compressed air.
high spots which will cause an increased
drag on the stones. Move the hone up
and down the bore with short overlapping
strokes about I " long. Concentrate on the
high spots in the first cut. As these are
removed, the drag on the hone will
become lighter and smoother. Do not
hone as long at the air inlet port area as in
the rest of the bore because this area, as
a rule, cuts away more rapidly. Feed
lightly to avoid an excessive increase in
the bore diameter. Some stones cut
rapidly even under low tension.
d. When the bore is fairly clean, remove the
hone, inspect the stones and measure the
bore. Determine which spots must be
honed most. Moving the hone from the
top to the bottom of the bore will not
correct an out-of-round condition. To
Fig. 13. Cylinder Bore Measurement Diagram
remain in one spot too long will cause the
bore to become irregular. Where and how
much to hone can be judged by feel. A
heavy cut in a distorted bore produces a
steady drag on
10-2-9
