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OVERHAULING PROCEDURE
Judging When to Overhaul the Engine
Usually
the overhauling time of the engine is determined by reduced
engine power, decreased compression pressure and increased fuel and
engine oil comsumption.
But the reduced engine power may be caused not only by the trouble of
the engine itself but also by damaged nozzle or improper adjustment of
the injection pump.
For this reason,
it will be most advisable to
take
a
compression
check
of
the
engine
before
undertaking
major
overhaul.
However, the decrease in compression pressure is caused by many fctors
and it is not so easy to find which factor is the cause.
Therefore,
the cause for trouble should be determined on the basis of records of
regular inspection and maintenance.
If the trouble is caused by the wear of the cylinder and piston, the
following symptoms will appear.
1)
Reduced engine power and decreased compression pressure
2)
Increased fuel consumption
3)
Increased consumption of lubricating oil
4)
Poor engine starting
5)
Increased noise from engine parts
Usually, two or more of the above symptoms appear at the same time.
Symptoms 2)
and 4)
are caused by excessive fuel injection, improper
injection
timing
and
plunger
and
nozzle
wear,
and
they
are
also
ser iously affected by electr ical system trouble such as faulty bat-
tery,
alternator,
starter
and
glow plug.
Therefore,
in order
to
determine the overhauling time of the engine, it is recommended to use
as a guide the decrease of the compression pressure due to the wear of
the
cylinder
and
piston aand
at
the
same
time
to
take
into con-
sideration the oil consumption and other items.
The compression pressure is the source of the explosive power of the
diesel engine, and without sufficient compression pressure, complete
combustion cannot be achieved even if other parts of the engine are
normal.
In order to determine the overhauling time of the diesel engine, it is
important to measure the engine compression pressure regularly.
Since
the compression pressure varies with engine RPM, check the speed also.
The engine RPM can be measured at the front end of the crankshaft.
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