TM 5-4310-227-15
7
Roller bearing cup (2 rqr)
Screw, cap, hex-hd, 3/8-16 X 1 in. (4 rqr)
20
8
Washer, lock, 3/8 in. (4 rqr)
Compression ring
21
9
Compression and scraper ring (2 rqr)
22
Gasket, 0.003 in.
10
Oil ring
23
Gasket, 0.006 in.
11
Piston
24
Cone and roller (2 rqr)
12
Cylinder and crankcase assembly
Retaining ring (2 rqr)
26
13
Piston pin
26
Connecting rod
14
Key, machine, 1/4 X 1/4 X 2 1/2 in.
Sleeve bearing
27
15
Crankshaft
28
Bolt, shoulder, 5/16 X 7/8 in. (2 rqr)
16
29
Rod cap
Connecting rod shim (2 rqr)
17
Nut, plain, hex, 5/16-24 (2 rqr)
30
Key, woodruff, No. 6
18
Nut, stamped, 5/16-24 (2 rqr)
Crankshaft gear
31
19
Drive pulley end plate
Figure 4-11-Continued.
Thoroughly clean the
they are not in direct line with one
Caution:
another or the piston pin ends.
cylinder and crankcase assembly af-
(5) Position the two shoulder bolts (28)
ter a reboring or honing operation to
in the connecting rod (13).
remove all foreign particles, then ap-
(6) Apply a light film of clean lubrica-
ply a light coat of clean lubricating
tion oil to the crankshaft journal, cyl-
oil to the cylinder bore.
inder bore, piston, and connecting rod
assembly bearing surfaces.
c. Reassembly and Installation.
(7) Then install a piston ring compressor
(1) Press the sleeve beating (27) into the
on the piston (11) and push the pis-
connecting rod (13). Ream the inside
ton and connecting rod into the cyl-
diameter of the sleeve bearing 0.75050
inder bore until the piston head leaves
to 0.75080 inch. Remove any sharp
the piston ring compressor and reach-
edges on the sides of the sleeve bear-
es a point slightly below the top of
ing.
the cylinder bore.
(2) Apply a light film of clean lubricat-
ing oil on the piston pin (26). Install
Caution: Be sure to guide the con-
the piston pin partially into the piston
necting rod down through the cylin-
(11), then install the connecting rod
der bore to avoid damaging the crank-
(13). Finish installing the piston pin
shaft journal.
through the sleeve bearing (27) in
(8) Turn the crankshaft throw to the bot-
the connecting rod and the opposite
tom of its stroke, then push the pis-
s i d e of the piston, and secure the
ton all the way down until the con-
piston pin at each end with a retain-
necting rod bearing surface seats on
ing ring (12).
the crankshaft journal.
(3) After the connecting rod is assembled
(9) Wipe the excess oil from the crank-
to the piston, inspect for a bent or
shaft journal and measure the fit of
twisted rod on a suitable alinement
t h e connecting rod bearing or the
I f the connecting nod is
fixture.
crankshaft as follows:
twisted or bent it should be straight-
(a) Place a length of plastic gage on
ened or replaced.
the bearing surface of the rod cap
(4) Using a piston ring expander tool, in-
(16).
stall new piston rings (8, 9 and 10)
(b) Install the 2 shims (29) and the
in the proper sequence on the piston
rod cap (16) cm the connecting rod
(11). Install the oil ring (10) first,
(13 and secure with the 2 nuts
t h e two compression and scraper
(17). Torque the nuts to 16 to 18
rings (9), then the top compression
foot-pounds.
ring (8). Stagger the ring gaps so
4-29
