TM 5-3810-300-24&P-3
BLOWER 3.4
Fig 1 - Blower and Drive Assembly and Accessories Including Mechanical Governor Atta ched to Standard Blower or Small Diameter
Rotor Blower (71 Engines)
2 Housing--Blower
20 Hub--Rotor Drive Gear
40
Coupling Assy.--
102
Elbow (900)--Oil Line
3 Rotor--Blower--Upper
21 Bolt--Plate to Gear
Water Pump Drive
to Blower Drive
R.H. Helix
22 Bolt--Plate to Hub
41
Bolt--Allen Head--
103
End Plate--Cylinder
4 Rotor--Blower--Lower
23 End Plate--Front
Coupling
Block--Rear
L.H Helix
24 End Plate--Rear
42
Gear--Blower
104
Housing--Flywheel
5 Bearing (Roller)-
27 Oil Seal--End Plate
Drive
105
Fork--Fuel Pump Drive
Front
28 Cover--End Plate--Front
48
Support--Blower Drive
106
Cover--Water Pump
9 Bearing (Ball)--Rear--
29 Cover--End Plate--Rear
Gear Hub
Inlet
Double Row Thrust
33 Cover--Blower Drive
53
Coupling Assy.--
114
Clamp--Drive Cover
13 Gear--Rotor--Upper
Shaft
Blower Drive
Seal
R.H Helix
37 Seal--Drive Shaft
99
Pump--Fresh fater
115
Plate--Blower Rotor
14 Gear--Rotor--Lower
Cover
100 Governor
Drive Hub
L.H Helix
38 Shaft--Blower Drive
101 Pump--Fuel
116
Spacer--Plate to Gear
presence of oil on the blower end plates and rotors or the
Lubrication
inside surfaces of the housing. This condition may be
Oil drains from the valve operating mechanism on the
checked by running the engine at low speed and
cylinder head into the camshaft pocket (A and C
directing a light into the rotor compartment at the end
engines) or balance shaft pocket (B and D engines) in
plates and the oil seals. A thin film of oil radiating away
the cylinder block; then, when it reaches a certain level,
from the seals is indicative of an oil leak.
the oil flows from the pocket into cavities at the upper
corners of the blower and through passages in the
A worn blower drive, resulting in a rattling noise inside
blower and end plates to lubricate the bearings, governor
the blower, may be detected by grasping the top rotor
and water pump drives at the front end, and bearings
firmly and attempting to rotate it. Rotors may move from
and gears at the rear end of the blower. A slinger
3/8" to 5/8", measured at the lobe crown, with a springing
attached to the front end of the lower rotor shaft throws
action. When released, the rotors should move back at
oil into the front roller bearings and governor weights. A
least 1/4". If the rotors cannot be moved as directed
dam in the blower end plates maintains oil at a level
above, or if the rotors move too freely, the flexible blower
adequate to submerge the lower portion of the slinger
drive coupling should be inspected and replaced if
and the driven gear.
necessary.
Surplus oil overflows the dams in the end plates and
If the drive coupling is worn, the blower drive gear
returns through two drilled holes in the cylinder block to
assembly may be removed from the cylinder block end
the engine crankcase. On the former blower, the oil dam
plate after the blower has been removed from the engine
was located in the blower end plate cover.
and the drive gear hub bearing support to cylinder block
Inspection of Blower
end plate bolts are removed, see Section 1.7.6.
The blower may be inspected for any of the following
conditions without being removed from the engine.
Loose rotor shafts or damaged bearings will cause
However, the air shut-down housing must be removed.
rubbing and scoring between the crowns of the rotor
CAUTION: When inspecting a blower on
lobes and the mating rotor roots, between the rotors and
an engine with the engine running, keep
the end plates, or between the rotors and the housing.
fingers and clothing away from the moving
Generally, a combination of these conditions exists. A
parts of the blower and run the engine at low
loose shaft usually causes rubbing between the rotors
speeds only.
and the end plates. Worn or damaged bearings will
Dirt or chips, drawn through the blower, will make deep
cause rubbing between the mating rotor lobes at some
scratches in the rotors and housing and throw up burrs
point or perhaps allow the rotor assemblies to rub the
around such abrasions. If burrs cause interference
blower housing. This condition will usually show up at the
between the rotors or between the rotors and the
end where the bearings have failed.
housing, the blower should be removed from the engine
and the parts dressed down to eliminate the interference,
Excessive back-lash in between the blower timing gears
or the rotors must be replaced if they are too badly
usually results in the rotor lobes rubbing throughout their
scored.
entire length.
Leaky oil seals are usually manifested by the
To correct any of the above conditions, the blower must
be removed from the engine and either repaired or
replaced.
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