Technical data

MAINTENANCE
1. Judging , Engine Overhaul Period
Generally the time at which an engine should be overhauled is determined by lowered engine power,
decreased cylinder compression pressure and increased fuel and lubricating oil consumption.
The lowered engine power, in the case of diesel engines, is not necessarily due to a trouble of the engine
itself but is sometimes caused by worn or damaged injectors and/or worn or damaged injection pump. It
is most reasonable to judge by a decrease in compression pressure. The decrease in compression pressure
is caused by many factors. It is, therefore, necessary to determine a cause or causes of the trouble on the
basis of data of periodic inspection and maintenance.
When the trouble is caused by a worn cylinder or piston ring, the following symptoms will occur:
1. Low engine power, and a decrease in compression pressure.
2. Increased fuel consumption.
3. Increased lubricating oil consumption.
4. Poor engine starting.
5. Loud noise in engine parts.
Actually these symptoms often appear together. The symptoms (2) and (4) result also from excessive fuel
injection, improper injection timing, and wear of plunger and nozzle. Defective electrical parts, such as
the battery, alternator, starter and glow plug will become a major cause of engine trouble. Therefore, it
is desirable to judge the period to overhaul the engine by the lowered compression pressure caused by
worn cylinders and pistons plus increased oil consumption and other.
In diesel engines, satisfactory combustion is obtained only when the fuel and air are compressed
sufficiently. When sufficient compression pressure is not obtained, incomplete combustion of fuel will
take place even if other parts of engine are operating properly.
To judge the period of engine overhaul, 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.