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