A loose shaft usually causes rubbing be-
removed from the engine. However, the
tween t h e r o t o r s a n d t h e e n d p l a t e s .
air shut-down housing must be removed.
Worn o r d a m a g e d b e a r i n g w i l l c a u s e r u b -
bing between the mating rotor lobes at
some point or perhaps allow the rotor as-
semblies t o r u b t h e b l o w e r h o u s i n g .
This condition will usually show up at
When inspecting a blower on an
the end where the bearings have failed.
engine with the engine running,
keep fingers and clothing away
Excessive backlash in between the blower
f r o m the moving parts of the blow-
timing gears usually results in the rotor
er
and
run
the
engine
at
low
lobes rubbing throughout their entire
s p e e d s only.
length.
To correct any of the above conditions,
Dirt or chips drawn through the blower
remove the blower from the engine and
will make deep scratches in the rotors
either repair or replace it.
and housing and throw up burrs around
such abrasions. If burrs cause interfer-
Inspect the blower inlet screen period-
ence between the rotors or between the
ically, for an accumulation of dirt which,
rotors and housing, remove the blower
after prolonged operation, may affect the
from the engine and dress the parts
air flow.
Servicing of the screen con-
down to eliminate the interference, or
sists of thoroughly washing it in fuel oil
replace the rotors if they are too badly
and cleaning with a stiff brush until the
scored.
screen is free of all the dirt deposits.
Leaky oil seals are usually manifested by
the presence of oil on the blower end
Remove Blower
plates and rotors or the inside surfaces
This condition may be
of the housing.
In most cases, r e m o v a l o f t h e b l o w e r , t o -
checked by running the engine at low
gether with the governor drive, fresh
speed and directing a light into the rotor
water pump, fuel oil pump and the blow-
compartment at the end plates and the oil
er drive shaft cover, will be found most
seals.
A thin film of oil radiating away
advantageous.
For removal of this as-
f r o m the seals is indicative of an oil leak.
s e m b l y , refer to Figure 11D-4 on page
11D-5 and proceed as follows:
A worn blower drive, resulting in a rattl-
ing noise inside the blower, may be de-
1. Drain the cooling system.
tected by grasping the top rotor firmly
R o t o r s may
and attempting to rotate it.
2. Remove the governor control housing
move from 3/8" to 5/8", measured at the
assembly
as
outlined
under
"Remove
lobe crown, with a springing action.
Governor" in Subsection 11C.
When released, the rotors should move
If the rotors cannot
back at least 1/4".
3. Disconnect the fuel lines at the fuel
be moved as directed above, or if the ro-
tors move too freely, inspect the flexible
pump.
blower drive coupling and replace it if
4. Loosen the water pump connections at
necessary.
the pump cover and the cylinder block.
If the drive coupling is worn, the blower
5. Loosen the turbocharger hose clamps
drive gear assembly may be removed
and slide the hose and clamps back on
from the cylinder block end plate after
the air inlet housing.
the blower has been removed from the
engine a n d t h e d r i v e g e a r h u b b e a r i n g
6. Remove the air inlet housing, gasket,
support to cylinder block end plate bolts
striker plate and air inlet screen from
are removed.
the blower.
Loose rotor shafts or damaged bearings
7. Remove the blower driver shaft as
will cause rubbing and scoring between
outlined in Subsection 11B.
the crowns of the rotor lobes and the
mating r o t o r r o o t s , b e t w e e n t h e r o t o r s
8. Loosen the blower drive shaft cover
and the end plates, or between the ro-
seal clamp at the blower drive gear hub
Generally, a
tors and the housing.
support.
combination of these conditions exists.
