TM 5-4310-276-14
(2) Piston-cylinder. Check fit before assem-
(6) When removing connecting rods (10 and
bling pistons to connecting rods. Piston without
21) from crankshaft by removing rod capscrews (1
rings must slide through the cylinder of their own
and 12) and lockwashers (2 and 13) from connecting
weight and holding the skirt of the piston with the
rods to be sure that rods and caps (11 and 22) are
two thumbs there should be no appreciable side mo-
kept in matched sets, noting the position with refer-
tion at any point of piston travel. Refer to table 1-2
ence to the crankshaft of the identification marks
for allowable clearance.
on one side of each so that the connecting rod can be
replaced in the same position it originally occupied.
(3) Wrist pin-piston. Wrist pins (4 and 15,
Remove bushings (9 and 20) only if worn or scored.
ton bores at ambient temperature. Be sure fibre
washers (3 and 14) at each end of the wrist pins (4
if replacement is necessary, by evenly spaced blows
and 15) are in place before assembling to cylinder.
from inside.
Assemble piston rings (5, 6, 7, 16 and 17) to pistons
b. Cleaning, Inspection and Repair.
(8 and 19). Top two rings are compression rings and
dot stamped on side of rings indicates top of ring.
Oil rings (7 and 18) cannot be installed upside down
as either position is correct.
Drycleaning solvent, P-D 680, used to
(4) Connecting rod-crankshaft. Install
clean parts is potentially dangerous to
bearing caps (11 and 22, fig. 7-4) and secure with
personnel and property. Avoid re-
washers (2 and 13) and screws (1 and 12). Tap cap
peated and prolonged skin contact,
lightly to make sure bearing is making contact and
Do not use near open flame or exces-
tighten rod bolts, Torque bolts to 8 foot-pounds. The
sive heat. Flash point of solvent is
combined piston and connecting rod should turn on
100F (38C).
the crankshaft of their own weight if bearing ad-
justment is correct. If tight, cut paper shims and in-
(1) Clean all parts with cleaning solvent, item
5, App, D, and dry thoroughly.
stall between cap and rod. If loose, file cap until fit
is sufficiently tight. Correct clearance between con-
(2) Examine cylinder bores for wear, scoring,
netting rod and crankshaft journal is 0.0011 inch to
pitting, cracks or other damage. Replace cylinder
0.0019 inch (0.0028 cm to 0.0048 cm). Refer to table
with damaged bores.
(3) Measure the clearance between small end
a. Reinstall crankshaft with pistons and
of connecting rod and wrist pin. Also measure the
crankshaft attached being careful not to damage oil
clearance between large end of connecting rod and
feeder ring (15, fig. 7-3) when fitting within lugs at
crankshaft. Refer to table 1-2 for allowable clear-
bottom of crankcase (19) and being sure there are
ances.
no burrs or dirt on the pulley end of the crankshaft
(4) Examine crankshaft and pistons for wear,
that might cut the oil seal (17). Replace oil feeder
scuffing, scoring, etc., and replace parts damaged. If
ring plate (11, fig. 7-l).
parts exceed clearance listed in table 1-2, replace
them.
slide on over crankshaft and press into place in the
(5) Inspect tapered roller bearing for rough,
crankcase, the lip or seal side toward the crankcase.
pitted, or scored surfaces. Replace a defective bear-
Do not hammer directly on the seal.
ing.
(5) Cylinder-crankcase. Coat bottom end of
c. Reassembly and Installation.
cylinder bores (8, fig. 7-1) and piston rings with oil
(1) Crankshaft-crankcase. Before assem-
and assemble cylinder over pistons. The bottom of
bling, the crankshaft (16, fig. 7-3) must be fitted to
the cylinder bores are chamfered and rings will
the crankcase (19). Install cover (10), gaskets (11
compress into piston grooves by pressing cylinder
and 12) and secure with end cover screws (9) evenly.
downward and twisting slightly from side to side.
End cover gaskets (11 and 12) serve as shims and
After cylinder is in place and before cap screws (9,
are furnished in two thicknesses and proper com-
bination must be selected so crankshaft (16) can be
three times for self-alignment. Tighten cap screws
spun in the bearings without end play. Refer to
(9) and torque to 18 foot-pounds. Install key (8, fig,
7-3) and flywheel pulley (7) after cylinder head and
feed ring (15) rotates freely on the crankcase. Re-
intercooler is assembled. Torque flywheel bolt to 43
move crankshaft from the crankcase and hold long
foot-pounds.
end in a vise using soft jaws to prevent damage.
7-8
