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TM5-4210-229-14&P
6-12. PISTON AND CONNECTING ROD MAINTENANCE (Continued).
The oil regulating ring coil spring must
be installed in the groove before the ring.
(7) Position the split of the top ring 30° from
the piston pin bore. Position the split of the
second ring 180° from the top ring and posi-
tion the split of the oil ring 90° from the
second.
b. Cylinder sleeve installation.
(1) Clean and dry the bore (in the crankcase)
and flange counterbore. Also clean and dry
the sleeve.
CAUTION
When a new piston or a new piston and con-
necting rod assembly are being installed,
install a matched set of pistons and sleeves.
(2) Cylinder sleeve protrusion check.
(a) Place each sleeve in the crankcase
without the O-rings. Clamp the sleeve
down using three holding adapters.
(Make sleeve holding adapters locally).
(b) Use one of the hardened washers under
each cap screw. Space the bolts to ob-
tain uniform pressure on this sleeve
flange. Torque the bolts in three stages:
40 ft-lb (55 N.m), 80 ft-lb (110 N.m)
and 120 ft-lb (165 N.m).
(c) Place a dial indicator, with block, across
the cylinder sleeve.
(d) With the dial indicator set on the flange
of the cylinder sleeve, adjust the indi-
cator to zero. Move the indicator block
until the pointer drops to the crankcase
deck and take a reading.
(e) If the sleeve flange is below the crank-
case deck, rest the indicator pointer on
the crankcase deck and set the indica-
tor at zero. Move the indicator block
until the pointer drops to the sleeve
flange and take a reading.
(f) Take readings at three or four points
around the sleeve and use the average
reading to determine which shim, if any,
is needed to bring the protrusion within
the 0.002 to 0.005 in (0.05 to 0.13 mm)
specification.
(3) Shim and O-ring installation.
(a) Remove the clamping bolts and washers.
Clean the top deck of the crankcase and
the cylinder sleeve counterbore. Clean
the sleeve.
(b) Install the shin (if necessary) in the
counterbore.
(c) Coat the sealing O-rings with clean oil
(Appendix D, Item 37) and install them
into the grooves in the sleeves (without
twist). The rings must be installed in
the following order: bottom, center
and top.
CAUTION
Be sure the O-ring is properly aligned in the
groove.
(d) Brush the sealing ring contacting sur-
face in the crankcase with clean oil (Ap-
pendix D, Item 37).
(e) Install the sleeve carefully into the same
bore it was removed from. Press into
place by hand.
6-34
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