TM 5-3810-300-24 & P3
Cylinder Block
1.1
and the block is desirable. However, a good fit between the
inspect the stones and measure the bore. Determine
cylinder liner and block may be obtained by comparing the
which spots must be honed most. Moving the hone
average bore sizes with Table 1.
from the top to the bottom of the bore will not correct
an out-of-round condition. To remain in one spot too
4. If necessary, bore the cylinder block as follows:
long will cause the bore to become irregular. Where
and how much to hone can be judged by feel. A
a. Each bore in a used block must not be out-of round
heavy cut in a distorted bore produces a steady drag
or tapered more than .002". If the average block bore
on the hone and makes it difficult to feel the high
is over 4.6285", the block should be bored oversize
spots. Therefore, use a light cut with frequent stone
as shown in Table 2.
adjustments.
b. A typical commercially available portable boring bar is
e. Wash the cylinder block thoroughly after the honing
illustrated in Fig. 14. Instructions on correct use of
operation is completed.
the boring bar are provided by the manufacturer.
2. Check the cylinder block bores:
c. After boring the block for an oversize cylinder liner,
check the bore finish to be sure it is smooth (120
a. Visually check the contact area as revealed by the
RMS). Heat transfer from the cylinder liner to the
honed surface. There must not be any low spots
block will be adversely affected if the block bore isn't
which are larger in area than a half dollar.
smooth.
b. Measure the entire bore of each cylinder with cylinder
bore gage J 5347 (Fig. 11) which has a dial indicator
d. Wash the block thoroughly after the boring operation.
calibrated in .0001 "increments. The standard block
bore is 4.6260" to 4.6270". First, place the bore gage
e. When an oversize liner is used, stamp the size of the
in the master ring gage J 8386-01 which has an I.D.
liner on the top deck of the block adjacent to the liner
of 4.6270" and set the dial to zero. Next rotate the
counterbore.
An oversize liner insert must be
dial clockwise .0005" to give a zero dial indicator
installed whenever an oversize liner is used (Section
setting of 4.6265". Take measurements on the
1.6.3).
cleaned-up surface only at positions A, B, C, D, E and
F in the bore on axes 90 apart (Fig. 12). Read the
5. Check the top of the block for flatness with an accurate
measurements from the zero mark on the gage.
NOTE: Dial bore gage setting master tool
a. The top surface of the block must not vary more than
J 23059 may be used in place of the master
.003" transversely and not over .009" longitudinally. It
ring gage.
will be difficult to prevent water, oil and compression
leaks if the top surface of the block exceeds these
c. The cylinder block is alternately expanding and
tolerances.
contracting, during engine operation, due to
temperature variations.
This may result in
b. If it is necessary to machine the top surface of the
irregularities in the block bores (out-of-round and
block to correct for the above conditions, do not
taper), the effects of which will be seen as high
remove more than .008" of metal. Stamp the amount
pressure areas on the outside of the cylinder liner
of stock removed on the face of the block. The
distance from the centerline of the crankshaft to the
d. If a new liner and piston is installed in the block
top of the block must not be less than 16.176"(Fig.
without properly fitting the liner, galling and seizing of
the piston may result. This is caused by the new
piston having to travel over the irregularities without
c. If stock is removed from the top surface of the block,
time to conform to the particular shape of the block
check the depth of the seal ring grooves and
bore.
counterbores. The cylinder head seal strip grooves
must be .092"-.107" deep. The large water hole
3. Fit the liner to the cylinder block: a. The liner-to-block
counterbores (between the cylinders) must be .109"-
clearance with new parts is zero to .002". With used parts, the
.120" deep, and the combination water and oil hole
maximum liner-to block clearance is .0025". Examine the
counterbores and small water hole counterbores
block bore measurements to determine if standard or .001"
must be .087"-.098" deep. If necessary, deepen the
oversize O.D. liners can be used, or if the Pa, cylinder block
grooves or counterbores to
should be bored oversize. A light push fit between the liner
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