Thread the bolt into the left hand he-
G. T h r e a d a n i n s t a l l e r s c r e w J 6 2 7 0 - 8 i n
lix rotor shaft and guide the lugs on
the end of each rotor shaft until it
the disc in the slots in the gear hub.
Place gear installer J 6270-7
bottoms.
Then bend one of the tangs on the
over the installer screw and against
lock washer over into the slot in the
the right hand helix gear, and gear
disc. Tighten the gear retaining bolt
installer J 6270-6 over the installer
to 55-65 lb-ft (75-88 Nm) torque.
screw and against the left hand helix
gear. Then thread a nut on each in-
L. Bend one of the tangs of each lock
staller screw (see Figure 11D-19).
washer over against the head of the
gear retaining bolt. Remove the cloth
from the blower rotors.
Timing Blower Rotors
After the blower rotors and timing gears
are installed, the blower rotors must be
timed.
The blower rotors, when properly posi-
tioned in the housing, run with a slight
clearance between the lobes. T h i s c l e a r -
ance may be varied by moving one of the
helical gears in or out on the shaft rela-
tive to the other gear.
Figure 11D-19. Installing Rotor
Gears on Rotor Shaft
If the right hand helix gear is moved
out, the right hand helix rotor will turn
counterclockwise when viewed from the
H. Place a clean shop towel between the
If the left hand helix gear is
gear end.
rotors, and another one between the
moved out, the left hand helix rotor will
rotor and the housing to prevent the
turn clockwise when viewed from the
Then turn the
rotors from turning.
gear end. This positioning of the gear,
nuts on the installer screws clockwise
to obtain the proper clearance between
as shown in Figure 11D-19 and force
the rotor lobes, is known as blower tim-
the gears into position tight against
ing.
the shims and bearing inner races.
Moving the gears OUT or IN on the rotor
NOTE
shafts is accomplished by adding or re-
moving shims between the gears and the
Both gears must be pressed on the
r o t o r shafts at the same time.
The clearance between the rotor lobes
should be checked with 1/2" feeler gaug-
Remove the rotor timing gear instal-
I.
es in the manner shown in Figure 11D-20
lers from the rotor shafts.
on page 11D-15. When measuring clear-
ances of more than 0.005", laminated
Place a lock washer (16) and gear re-
J.
taining washer (19) on one of the
feeler
gauges
that
are
made
up
of
0.002", 0.003" or 0./005" feeler stock
gear retaining bolts (15). Thread the
a r e more p r a c t i c a l a n d s u i t a b l e t h a n a
bolt into the right hand helix rotor
Clearances should
single feeler gauge.
shaft and guide the lugs on the re-
be measured from both the inlet and out-
taining washer in the slot in the gear
l e t sides of the blower.
hub. Then bend one of the tangs on
the lock washer over into the slot of
A specially designed feeler gauge set J
Tighten the
the retaining washer.
1698-02 for the blower clearance opera-
gear r e t a i n i n g b o l t t o 5 5 - 6 5 l b - f t
tion is available. Time the rotors as fol-
(75-88 Nm) torque.
lows:
K. P l a c e a l o c k w a s h e r ( 1 6 ) a n d f u e l
1. Time the rotors to have 0.002" to
pump drive coupling disc (18) on the
0.006" clearance between the TRAILING
bolt.
retaining
gear
remaining
