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TM5-4210-229-14&P
6-12. PISTON AND CONNECTING ROD MAINTENANCE.
This task cover: a. Removal
b. Inspection
c. Installation
INITIAL SET-UP
Tools
Universal Wet Sleeve Puller (PLT-502-3)
Arbor Press
Dial Indicator
Piston Ring Expander
Piston and Piston Ring Compressor (SE-1680)
General Mechanics Tool Kit
Equipment Condition
Para. Condition Description
4-92 Oil Pan Removed
6-6 Cylinder Head and Valves Removed
Materials/Parts
Piston Sleeve (682720C1)
Piston and Sleeve Kit (1802581C91)
Piston Ring Set (687429C91)
Piston Pin (670675C1)
Connecting Rod (688923C91)
Cleaning Solvent (Appendix D, Item 54)
Lubricating Oil (Appendix D, Item 37)
Molykote (Appendix D, Item 35)
Plastigage (Appendix D, Item 40a)
REMOVAL
NOTE
Check crankshaft bearing bolt torque on the
main bearing and connecting rod bolts
anytime the oil pan is removed.
a. Main bearing and connecting rod bolt torques
check.
(1) Using a direct reading torque wrench (not a
clicker type) place the socket over the bolt
head and gently pull the wrench in the
tightening direction to remove slack. Mark
the bolt and rod with the marks in align-
ment. For mains, mark the cap and the
socket.
(2) Loosen bolts 1/4 turn. Torque with a slow
steady motion and read the torque at the
moment the marks are once again aligned.
(3) On the main bearing bolts if torque is found
to be below 115 ft-lb (155 N.m), and cap is
not to be removed, back off 1/4 turn and
retorque to 115 ft-lb (155 N.m). Those at
115 ft-lb (155 N.m) or higher should be left
with marks aligned.
(4) For connecting rod bolts if the torque of
both bolts is 130 ft-lb (175 N.m) or higher,
and rod is not to be removed, they may be
left with the marks aligned.
(5) If the torque of either bolt is found to be less
than 110 ft-lb (150 N.m), the rod should be
removed and inspected.
(6) If the torque of both connecting rod bolts is
found to be at least 110 ft-lb (150 N.m), but
either or both less than 130 lb-ft (175 N.m),
the cap should be removed and the bear-
ing inspected.
NOTE
If bearing distress is noted or bearings are not a
tight fit in rod and cap, new inserts should be
used and the cap reinstalled. If no bearing dis-
tress is noted, reinstall the bearings and cap.
CAUTION
Before proceeding with piston and connecting
rod removal, inspect the sleeves at the upper
end of the ring travel for the presence of a
ridge. This ridge must be removed with a fine
emery cloth and a carbon scraper before the
piston is removed. This prevents damage to
the piston ring lands during removal and also
prevents damage to new piston rings when
installing the piston. When removing a piston
from the crank-case, do not allow the piston
skirt to strike the crankcase or the connecting
rod to strike the piston sleeve, as severe
damage to the sleeve could result.
6-28
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