Perkins 1104D NH1 Systems Operation Testing And Adjusting page 54

54
Testing and Adjusting Section
b. If crankcase pressure is high, or if the oil drain
is restricted, pressure in the center housing
may be greater than the pressure of turbine
housing (1). Oil flow may be forced in the wrong
direction and the oil may not drain. Check the
crankcase pressure and correct any problems.
c. If the oil drain line is damaged, replace the oil
drain line.
d. Check the routing of the oil drain line. Eliminate
any sharp restrictive bends. Make sure that
the oil drain line is not too close to the engine
exhaust manifold.
e. If Steps 4.a through 4.d did not reveal the
source of the oil leakage, turbocharger (3) has
internal damage. Replace turbocharger (3).
Inspection of the Wastegate
The wastegate controls the amount of exhaust gas
that is allowed to bypass the turbine side of the
turbocharger. This valve then controls the rpm of the
turbocharger.
When the engine operates in conditions of low
boost (lug), a spring presses against a diaphragm
in the canister. The actuating rod will move and the
wastegate actuator will close. The turbocharger can
then operate at maximum performance.
When the boost pressure increases against the
diaphragm in the canister, the wastegate will open.
The rpm of the turbocharger becomes limited. The
rpm limitation occurs because a portion of the
exhaust gases bypass the turbine wheel of the
turbocharger.
The following levels of boost pressure indicate a
problem with the wastegate:
•
Too high at full load conditions
•
Too low at all lug conditions
The boost pressure controls the maximum rpm of the
turbocharger, because the boost pressure controls
the position of the wastegate. The following factors
also affect the maximum rpm of the turbocharger:
•
The engine rating
•
The horsepower demand on the engine
•
The high idle rpm
•
Inlet air restriction
•
Exhaust system restriction
Check the Wastegate for Proper
Operation
Table 4
Required Tools
Part
Tool Number
21825617
A Dial Gauge
Illustration 51
Typical example
Note: The turbocharger is a nonserviceable item.
The pressure for the wastegate can be checked, but
not adjusted.
1. Disconnect the pipe for the boost sensor (6) at
the wastegate actuator (5). Connect an air supply
to the wastegate actuator that can be adjusted
accurately.
2. Install Tooling (A) to the turbocharger so that
the end of the actuator rod (1) is in contact with
Tooling (A). This will measure axial movement of
the actuator rod (4).
RENR7967
Part Description Qty
1
g01289484