ton and connecting rod assemblies on
The gap should not exceed 0.002 inch
the engine.
within a spread of any 4 inch on a
given plane.
Note. Check connecting rod bearing clear-
ances by inserting a piece of feeler stock,
(12) I n s p e c t t h e c o n n e c t i n g r o d a n d c a p
o n e - h a l f - i n c h - w i d e and 0.045-inch-thick,
f o r cracks, breaks, or other damage.
lengthwise between the crankshaft and bear-
I n s p e c t the bearing seating and mat-
ing. Install the bearing cap and torque to
85 to 95 foot-pound. A definte drag should
ing surfaces for nicks, burrs, and
be felt requiring pressure and possibly force
s c r a t c h e s . Replace all damaged or de-
to move rod from side-to-side. Remove the
fective parts.
cap and bearing and remove the feeler stock.
Reinstall cap and bearing and torque to 85
100. Piston and Connecting Rod Assemblies
to 95 foot-pound. Check connecting rod aide
clearance on the crankshaft. Correct clear-
Reassembly and Installation
ance is 0.008 to 0.012 inch. Check all con-
a. Reassembly. Refer to figure 33, and reas-
necting rod bearing clearance and side clear-
ance in the same manner.
s e m b l e the piston and connecting rod assem-
blies in the reverse order.
(2) Install the oil pump (par. 96).
Note. Install the sleeve (17) in the engine block by
( 3 ) Install the cylinder head and valves
using a block of wood and hammer to drive the sleeve
( p a r . 80).
down flush with the engine block.
(4) Install the engine housing (TM 5-
b. Installation.
3820-205-20/l).
(1) Refer to figure 32, and install the pis-
( 5 ) Install the engine assembly (par. 29).
S e c t i o n X V I I . CAM S H A F T , BEARI N G S , T A P P E T S , AN D T A P P E T GU I D E S
Se
d. Remove the cylinder heads and valves
101. General
(par. 78).
The camshaft used in this engine is a solid,
e. Remove the oil pump assembly (par. 94).
one-piece shaft. It is supported by four evenly
s p a c e d , sleeve-type bearings. The bearings are
f . Refer to figure 27, and remove the cam-
p r e c i s i o n bushings which are pressed into the
s h a f t thrust plate.
b l o c k bearing supports. At the center of the
g. Secure the valve tappets (7, fig. 34) in a
c a m s h a f t there is a helical gear which is an
raised position and remove the camshaft.
integral part of the camshaft. This gear is
supported by its own bearing to compensate for
h. Remove the 12 valve tappets (7, fig. 34)
from their guides in the block.
side thrust developed by the action of the gear
as it drives the tachometer drive. The cams lift
i. Do not replace the tappet guide (8) un-
flat-faced tappets, which move in tappet guides
l e s s they are worn or damaged. Measure the
t h a t are pressed into the block.
diameter of the guides with an inside microme-
t e r . The proper diameter is 0.4985 to 0.4995
inch. If the guides are worn more than 0.5015
102. Camshaft, Bearings, Tappets, and
inch press the guides from the engine block.
Tappet Guides Removal
j. Do not replace the camshaft bearings (2,
a . Remove the oil cooler and tappet covers
3 , 4, 5, and 6) unless they are worn or other-
(TM 5-3820-205-20/l).
w i s e damaged. Measure the bearings with an
inside micrometer. The proper diameter is
b . Remove the timing gears and end plate
2 . 2 4 9 5 to 2.2500 inches. If the bearings are
a s s e m b l y (par. 86).
w o r n greater than 2.2515 inches remove the
c. Remove the tachometer drive (TM 5-
b e a r i n g s by pressing them out of the engine
3820-205-20/l).
block.
AGO 8498A