DETROIT DIESEL
The deflector vanes impart a swirling motion to the air
large foreign particles which might seriously damage
entering the air cleaner and centrifuge the dust
the blower assembly.
particles against the walls of the tubes. The dust
particles are then carried to the dust bin at the bottom
of the cleaner by approximately 10% bleed-off air and
Air Box Drains
are finally discharged into the atmosphere. The
cleaner panel is fully effective at either high or low
During normal engine operation, water vapor from
velocities.
the air charge, as well as a slight amount of fuel and
lubricating oil fumes, condenses and, settles on the
The remainder of the air in the cleaner reverses
bottom of the air box. This condensation is removed
direction and spirals back along the discharge tubes
by the air box pressure through air box drain tubes
again centrifuging the air. The filtered air then
mounted on the side of the cylinder block.
reverses direction again and enters the replaceable
The air box drains must be open at all times. With the
filter element through the center portion of the
engine running, a periodic check is recommended for
discharge tubes. The air is filtered once more as it
a i r flow from the air box drain tubes. Liquid
passes through the pleats of the impregnated paper
accumulation on the bottom of the air box indicates a
element before leaving the outlet port of the cleaner
drain tube may be plugged. Such accumulations can be
housing.
seen by removing the cylinder block air box cover(s)
and should be wiped out with rags or blown out with
The cleaner panel tends to be self-cleaning. However,
compressed air. Then remove the drain tubes and
it should be inspected and any accumulated foreign
connectors from the cylinder block and clean them
material removed during the periodic replacement of
thoroughly.
the impregnated paper filter element. Overloading of
the paper element will not cause dirt particles to by-
Some engines are equipped with an air box drain
pass the filter and enter the engine, but will result in
check valve. Refer to the Lubrication and Preventive
starving the engine for air.
Maintenance section of this manual for service
instructions.
The filter element should be replaced, as operating
conditions warrant, as follows:
Crankcase Ventilation
I. Loosen the wing nuts on the fasteners and swing the
retaining bolts away from the cleaner panel.
Harmful vapors which may form within the engine are
removed from the crankcase, gear train and valve
2. Lift the cleaner panel away from the housing and
compartment by a continuous, pressurized ventilation
inspect it. Clean out any accumulated foreign material.
system.
3. Withdraw the paper filter element and discard it.
A slight pressure is maintained within the engine
crankcase by the seepage of a small amount of air
4. Install a new filter element.
from the airbox past the piston rings. This air sweeps
up through the engine and is drawn off through a
5. Install the cleaner panel and secure it in place with
crankcase breather.
the fasteners.
In-line engines are equipped with a breather assembly
which is mounted on the rocker cover or the flywheel
Air Silencer
housing. The 6V engines incorporate a breather
assembly mounted inside of the upper engine front
The air silencer, used on some marine engines, is
cover.
bolted to the intake side of the blower housing. The
silencer has a perforated steel partition welded in
The wire mesh pad (element) in the breather
place parallel with the outside faces, enclosing flame-
assemblies should be cleaned if excessive crankcase
proof, felted cotton waste which serves as a silencer
pressure is observed. If it is necessary to clean the
for air entering the blower.
element, remove the breather housing from the
flywheel housing (In-line engines) and the upper
While no servicing is required on the air silencer
engine front cover (6V engines). Wash the element in
proper, it may be removed when necessary to replace
fuel oil and dry it with compressed air. Reinstall the
the air inlet screen. This screen is used to filter out any
element and the breather assembly.
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