9. Intake/exhaust system
163
Special inspection of turbocharger
You should check the radial and axial clearance of a
rotor. This preventive action is to find the bearing wear
status of the axial clearance so as to prevent the severe
damage to the rotor and bearing.
Item
Cautions
Reasons
Starting an engine
1) Check the oil amount
2) Therefore, start the engine with the starter
motor to check the rise of oil pressure (until the
gradation of the oil pressure gauge moves or
the pressure indicator lamp is turned on).
2) Overhasty start of engine leads to
engine rotation without lubricating turbo-
charger and other engine parts, causing
abnormal wear or burning of bearings.
3) If you replace oil, oil filter cartridge, or lubri-
cation system parts or use an engine in cold
areas, or the engine has stopped for a long
period, loosen the oil pipe joint at the inlet of
the turbocharger and run the starter motor until
oil flows out. After completing the work, tighten
the oil pipe joint again and start the engine.
3) When an engine has stopped or kept
cold for a long period, circulation of oil in
the pipe gets poor.
After starting an engine
1) Operate the engine at idle for five minutes
from starting it.
1) When the engine is suddenly loaded
while the engine and the turbocharger
have not been smoothly rotated after
starting the engine, parts with insufficient
oil may be burnt.
2) Check if oil, gas, or air is leaked from each
part. If so, take proper action.
2) Leakage of oil, gas, or air (especially
oil) reduces oil pressure and loss of oil
cause burning of bearings.
During Operation
check the following.
1) Oil pressure
At idle: 1.5 ~ 3.0 kg/cm
2
Fully loaded: 3.0 ~ 5.5 kg/cm
2
1) Too low oil pressure causes abnormal
wearing or burning of bearings. Too high
oil pressure causes oil leakage.
2) When abnormal noise or vibration occurs,
slowly reduce the rotate count until the engine
stops and then figure out the causes.
2) Operating an engine with noise or
vibration may cause irreversible damage
of the engine.
Stopping an Engine
1) Operate the engine at idle for five minutes
before stopping it.
1) Sudden engine stop after operating
the engine under high load allows the
heat from the red-heated turbine blade to
be delivered to the bearing system. Then
oil burns and the bearing metal and rota-
tion shaft are burnt.
