Perkins L4 Workshop Manual - L-36 Fleet

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FILTERS
A prime consideration in the maintenance of
Diesel engines is that of cleanliness. The air and
fuel oil that enters the cylinders must be scrupulously
clean and so also must the lubricating oil.
In the Perkins L4 Diesel engine particular
attention bas been paid to the provision of means
foT ensuring cleanliness in respect of these.
Three filtration systems are provided: Air,
Fuel Oil and Lubrication, and all that the operator
needs to do is to take steps to ensure that the
filters are kept in such a state that they will most
effectively perform their functions.
Fig. G J . Gil Bath Air Filter
AIR Fn. TERS
Air is filtered as it enters the inlet manifold by
use of ODe or the other of the followmg filters :
1. Dil Bath type.
2. Air Maze type (Tractor type).
The system of operation of the air filters afford
a high measure of protection to the engine if
properly maintained.
The time for cleaning the air cleaner depends on
operating conditions, therefore under extreme
dusty conditions, the time limit recommended in
the periodical attentions for cleaning should be
decreased. (See Section F).
The correct maintenance of the air cleaner will
greatly assist in reducing bare wear, thereby
extending the life of the en'gine.
Oil Bath Type Filter.
In this type of filter the incoming air impinges
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upon the surface of the oil carried in a reservoir
in the lower part of the filter casing.
As aresuit, particles of foreign matter are
carried into the oil by their own momentum and
are there trapped. The air then passes through a
steel wire element before Teaching the indu~tion
manifold and in that element are deposited any
other particles of foreign matter which sti!l remain
in the air af ter its contact with the oil.
Maintenance.
Examine and replenish oil and clean in accor.
dance with periodical attentions. Section F.
Remove top cover and lift out element. Wash
in paraffin or fuel oil and allow to drain.
Empty oil from outer cas~ and scrape out
accumulated sludge. Wash outer case with paraffin
or fuel oil and refill with oil to the level indicated
(do not overfill).
Replace element and top cover, care to be taken
to see that the joint ring is in good condition and
is sealing before tightening the top cover down.
Fig. G2. Pre-filter
Air Maze type (Tractor type).
In the tractor oil bath filter the air is drawn in
through the intake pipe and down through the
centre of the filter to the oil bath. Here the air
impinges upon the surf ace of the oil and particles
of foreign matter are carried into the oil by their
own momentum and trapped. Tbe air then
passes up the sides of the filter through the wire
male and out through the connection at the top.