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1106 Perkins - Turbocharger (Inspect and adjust)

Turbocharger - (1) Air intake (2) Compressor housing (3) Compressor wheel (4) Bearing (5) Oil inlet port (6) Bearing (7) Turbine housing (8) Turbine wheel (9) Exhaust outlet (10) Oil outlet port (11) Exhaust inlet

The turbocharger is mounted on the outlet of the exhaust manifold in one of two positions on the right side of the engine, toward the top of the engine or to the side of the diesel engine. The exhaust gas from the exhaust manifold enters the exhaust inlet (11) and passes through the turbine housing (7) of the turbocharger. Energy from the exhaust gas causes the turbine wheel (8) to rotate. The turbine wheel is connected by a shaft to the compressor wheel (3). As the turbine wheel rotates, the compressor wheel is rotated. This causes the intake air to be pressurized through the compressor housing (2) of the turbocharger.

Turbocharger with the waste gate - (12) Actuating lever (13) Wastegate actuator (14) Line (boost pressure)

(14) Line (boost pressure) (15) Waste gate solenoid

When the load on the 1106 Perkins engine increases, more fuel is injected into the cylinders. The combustion of this additional fuel produces more exhaust gases. The additional exhaust gases cause the turbine and the compressor wheels of the turbocharger to turn faster. As the compressor wheel turns faster, air is compressed to a higher pressure and more air is forced into the cylinders. The increased flow of air into the cylinders allows the fuel to be burnt with greater efficiency. This produces more power.

A wastegate is installed on the turbine housing of the turbocharger. The waste gate is a valve that allows exhaust gas to bypass the turbine wheel of the turbocharger. The operation of the waste gate is dependent on the pressurized air (boost pressure) from the turbocharger compressor. The boost pressure acts on a diaphragm that is spring loaded in the wastegate actuator which varies the amount of exhaust gas that flows into the turbine.

If a waste gate solenoid (15) is installed, then the wastegate is controlled by the engine Electronic Control Module (ECM). The ECM uses inputs from a number of engine sensors to determine the optimum boost pressure. This will achieve the best exhaust emissions and fuel consumption at any given motor operating condition. The ECM controls the solenoid valve, which regulates the boost pressure to the waste gate actuator.

When high boost pressure is needed for the motor performance, a signal is sent from the ECM to the waste gate solenoid. This causes low pressure in the air inlet pipe (14) to act on the diaphragm within the wastegate actuator (13). The actuating rod (12) acts upon the actuating lever to close the valve in the waste gate. When the valve in the wastegate is closed, more exhaust gas is able to pass over the turbine wheel. This results in an increase in the speed of the turbocharger.

When low boost pressure is needed for the 1106 Perkins engine performance, a signal is sent from the ECM to the wastegate solenoid. This causes high pressure in the air inlet pipe (14) to act on the diaphragm within the waste gate actuator (13). The actuating rod (12) acts upon the actuating lever to open the valve inthe wastegate. When the valve in the wastegate is opened, more exhaust gas from the engine is able to bypass the turbine wheel, resulting in an decrease in the speed of the turbocharger.

The shaft that connects the turbine to the compressor wheel rotates in bearings (4 and 6). The bearings require oil under pressure for lubrication and cooling. The oil that flows to the lubricating oil inlet port (5) passes through the center of the turbocharger which retains the bearings. The oil exits the turbocharger from the lubricating oil outlet port (10) and returns to the oil pan.

Inspect and adjust

The condition of the turbocharger will have definite effects on engine performance. Use the following inspections and procedures to determine the condition of the turbocharger. Inspection of the compressor and the compressor housing. Inspection of the turbine wheel and the turbine housing. Inspection of the wastegate.

Inspection of the Compressor and the Compressor Housing - Inspect the compressor wheel for damage from a foreign object. If there is damage, determine the source of the foreign object. Replace the turbocharger. Turn the rotating assembly by hand. While you turn the assembly, push the assembly sideways. The assembly should turn freely. The compressor wheel should not rub the compressor housing.

The turbocharger must be replaced if the compressor wheel rubs the compressor wheel housing. Inspect the compressor and the compressor wheel housing for oil leakage. An oil leak from the compressor may deposit oil in the aftercooler. If oil is found in the aftercooler, then drain and clean the aftercooler.

(1) Turbine housing (2) Compressor housing

Check the oil level in the crankcase. If the oil level is too high, adjust the oil level. Inspect the engine crankcase breather. Clean the 1106 Perkins engine crankcase breather or replace the engine crankcase breather if the engine crankcase breather is plugged. Remove the pipe for the oil drain. Inspect the drain opening. Inspect the oil drain line. Inspect the area between the bearings of the rotating assembly shaft. Look for oil sludge. Inspect the oil drain hole for oil sludge. Inspect the oil drain line for oil sludge in the drain line. If necessary, clean the oil drain line.

Inspection of the Turbine Wheel and the Turbine Housing - Remove the air piping from the turbine housing. Inspect the turbine for damage by a foreign object. If there is damage, determine the source of the foreign object. Replace turbocharger (2). Inspect the turbine wheel for the carbon and other foreign material. Inspect turbine housing (1) for carbon and foreign material. Replace the turbocharger, if necessary.

Turn the rotating assembly by hand. While you turn the assembly, push the assembly sideways. The assembly should turn freely. The turbine wheel should not rub turbine wheel housing (1). Replace turbocharger (2) if turbine wheel rubs turbine housing (1). Inspect the turbine and turbine housing (1) for oil leakage. Inspect the turbine and turbine housing (1) for oil coking. Some oil coking may be cleaned. Heavy oil coking may require replacement of the turbocharger.

Remove the pipe for the oil drain. Inspect the drain opening. Inspect the area between the bearings of the rotating assembly shaft. Look for oil sludge. Inspect the oil drain hole for oil sludge. Inspect the oil drain line for oil sludge. If necessary, clean the drain line. 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. If the oil drain line is damaged, replace the oil drain line. 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.

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 1106 Perkins engine rating, The horsepower demand on the engine, The high idle rpm, Inlet air restriction, Exhaust system restriction.

Check the Wastegate for Proper - Disconnect the pipe for the boost sensor (7) at the wastegate actuator (6). Connect an air supply to the wastegate actuator that can be adjusted accurately. Install Tooling to the turbocharger so that the end of the actuator rod (4) is in contact with Tooling (A). This will measure axial movement of the actuator rod (4).

Slowly apply air pressure to the wastegate so that the actuator rod (4) moves 1.0 mm (0.039 inch). Ensure that the dial indicator returns to zero when the air pressure is released. Repeat the test several times. This will ensure that an accurate reading is obtained. If the operation of the wastegate is not correct, the actuator rod (4) can be adjusted. Remove Tooling from the turbocharger.

When the air pressure is applied, loosen the nut (5) on the actuator. Remove the circlip (1). Remove the pin (2) from the actuator rod (4). When the air pressure is too low, adjust the end of the actuator rod (4) in order to reduce the length of the actuator rod (4). If the air pressure is too high, adjust the end of the actuator rod (4) in order to increase the length of the actuator rod (4). Install the pin (2) to the actuator rod (4). Install the circlip (1) to the actuator rod (4). Tighten the nut (5) to a torque of 5 Nm (44 lb in). If the air pressure is correct, remove the air supply. Remove Tooling. Install the pipe for the boost sensor (7).