TM 5-3810-289-34
lockplates; then advance to 140/150 ft. Ibs., figure 3-
(2)
Loosen all capscrews completely;
tighten to 45/50 ft. lbs. and scribe each capscrew head
to coincide with permanent mark on cap, or scribe each
cap in line with capscrew hex corner.
(3) Advance each capscrew 600 (one hex)
from position described in Step 2, this will align scribed
mark (or next corner of capscrew with mark on main
bearing cap.
Caution: Tighten capscrews on each side of
cap a little at a time and as evenly as possible until
proper positions are reached. Never use lead ribbon
or feeler gage to check main bearing clearance.
Doing so may result in unnecessary damage to main
bearing shells.
Figure 3-229. Crankshaft installation.
n.
Main Bearing Shell Replacement with
Crankshaft in Place. If the crankshaft has not been
removed from the engine, it is possible to install new
main bearing shells in the following manner:
(1) Remove one main bearing cap and
lower shell; turn crankshaft until drilled hole in main
bearing journal is visible.
(2) Insert a 7/32 inch by /2 inch pin with a
head 3/32 inch thick into drilled hole of crankshaft; turn
crankshaft so pin pushes against shell on opposite side
of locking tang. Shell will turn out as crankshaft is
rotated.
(3) Carefully remove all metal and/or foreign
material from oil passages in crankshaft and cylinder
block.
(4) Lubricate the shell to be installed; then
lay shell in proper position on crankshaft journal so
Figure 3-230. Main bearing cap with thrust ring in place.
turning the crankshaft will seat the shell locking tang into
recess in block.
(5) Use pin and turn shell into position;
remove pin.
(6)
Replace -lower shell, making sure
locking tang seats in recess of main bearing cap.
(7) Install new lockplates and position cap
against crankshaft; use template method to tighten
capscrews. Make sure crankshaft turns freely.
(8) If necessary, replace remaining shells
one pair at a time in the same manner. If bearing shells
have had considerable service, it is recommended that
all shells be replaced to assure that the 0.002 inch
maximum variation in oil clearance between adjacent
main bearing shells and journals is not exceeded.
o. Check Crankshaft End Clearance.
(1) Attach dial indicator securely to rear of
block with contact point of gage resting against
Figure 3-231. Torquing main bearing capscrews.
crankshaft flange end face.
(2) Using a small bar (or equivalent), pry
m. Template Method of Tightening Main Bearing
crank-
Capscrews.
(1) Tighten main bearing capscrews
alternately to 65/75 ft. lbs. to set shells, caps and
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