TM 5-3810-300-24&P-3
BLOWER 3.4
Fig. 25. Measuring "CC" and "C" Clearances Between Blower Rotor Lobes
i. Remove the rotor timing gear installers
b. Rotate rotors to bring omitted serrations
from the rotor shafts.
on the shaft in alignment and facing the
top of the blower housing (Fig. 28).
j. Place a lock washer (16) and the gear
retaining washer (19) on one of the gear
c. Install the same number and thickness of
retaining bolts (15). Thread the bolt into
shims on the rotor shafts that were
the right hand helix rotor shaft, and guide
removed at the time of disassembly.
the lugs on the retaining washer in the
slots in the gear hub, then bend one of the
NOTE: When rebuilding a blower with
tangs on the lock washer over into the slot
new rotors or new gears, first install the
of the retaining washer. Tighten the gear
gears on the rotor shafts without the
retaining bolt to 55-65 lb-ft torque.
shims, then check the clearances
between the rotors to determine the
k. Place a lock washer (16) and the fuel
location and thickness of shims to be
pump drive coupling disc (18) on the
used; refer to Fig. 28.
remaining gear retaining bolt. Thread the
bolt into the left-hand helix rotor shaft and
d. Lubricate the serrations of the rotor shafts
guide the lugs on the disc in the slots in
with engine oil.
the gear hub, then bend one of the tangs
on the lock washer over into the slot in the
NOTE: A center punch mark placed in
disc. Tighten the gear retaining bolt to 55-
the end of each rotor shaft at the omitted
65 lb-ft torque.
serrations will assist in aligning the gears
on the shafts.
l. Bend one of the tangs of each lock washer
over against head of gear retaining bolt.
e. Start the left-hand helix gear on shaft of
left-hand helix rotor with omitted serrations
8. Install the blower rotor timing gears on the
in the gear and the shaft in alignment.
former reduction blower (Fig. 12) as follows:
f. Thread an installer screw J 6270-8 in the
One serration is omitted on the drive end of each
end of the rotor shaft until it bottoms.
blower rotor shaft and a corresponding serration
Place the installer J 6270-6 over the screw
is omitted in each gear. Assemble the gears on
and against the gear, and thread a nut on
the rotor shafts with the serrations in alignment.
the installer screw.
a. Place the blower housing and rotor
g. Place a clean shop towel between the
assembly, air inlet side of housing facing
rotors, and another one between the rotor
up, on the bench with the rear end
and the housing to prevent the rotors from
(serrated end of rotor shaft) of the blower
turning. Then, turn the nut on the installer
facing the outside of the bench.
screw clockwise and press the gear on the
PAGE 266
