TM 5-3810-300-24 & P3
Cylinder Block
1.1
Block Boring
Liner 0.0.
Maximum Block Bore
Dimensions
Size
I.D. on a Used Block
CAST IRON BLOCK
4.631"
.005" Oversize
4.6325"
4.632"
4.636"
.010" Oversize
4.6375"
4.637"
4.646'
.020" Oversize
4.6475"
4.647"
4.656"
.030" Oversize
4.6575"
4.657"
TABLE 2
cracked cylinder block must be replaced by a new block.
5. After the test is completed, remove the plates, drain the
water jacket and blow out all of the passages in the block with
compressed air.
Inspect Cylinder Block
After cleaning and pressure testing, inspect the cylinder block.
Since most of the engine cooling is accomplished by heat
Fig. 14 Boring Cylinder Block with Portable Boring Bar
transfer through the cylinder liners to the water jacket, a good
liner-to-block contact must exist when the engine is operating.
use such cutting agents with a dry hone. Use 120 grit
Whenever the cylinder liners are removed from an engine, the
stones J 5902-14.
block bores must be inspected.
b. Insert the hone in the bore (Fig. 10) and adjust the
NOTE: Before attempting to check the block
stones snugly to the narrowest section.
When
bores, hone them throughout their entire
correctly adjusted, the hone will not shake in the
length until about 75% of the area above the
bore, but will drag freely up and down when the hone
ports has been "cleaned-up".
is not running.
1. Hone the block bores as follows:
c. Start the hone and "feel out" the bore for high spots
which will cause an increased drag on the stones.
a. Use a hone in which the cutting radius of the stones
Move the hone up and down the bore with short
can be set in a fixed position to remove irregularities
overlapping strokes about I " long. Concentrate on
in the bore rather than following the irregularities as
the high spots in the first cut. As these are removed,
with a spring-loaded hone.
Clean the stones
the drag on the hone will become lighter and
frequently with a wire brush to prevent stone loading.
smoother. Do not hone as long at the air inlet port
Follow the hone manufacturer's instructions regarding
area as in the rest of the bore because this area, as a
the use of oil or kerosene on the stones. Do not use
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,
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