Viiib-Ii - Piper Navajo PA-31 Service Manual

PIPER NAVAJO SERVICE MANUAL
In addition to the aforementioned
components, each engine is equipped with an
alternator, geared starter, hydraulic pump and pneumatic pressure pump. Engine mounts are
steel tubing construction attached at the fire wall and incorporate vibration absorbing
dynafocal mounts. The two top exhaust stacks and extensions are positioned one for the
left and one for the right bank of cylinders. From the exhaust stacks, gases are directed to
the turbocharger exhaust plenum, through or around the turbo turbine, as required, and
overboard at the bottom of the engine nacelle.
The lubrication system is of the pressure wet sump type. The oil pump, which is located
in the accessory housing, draws oil through a drilled passage leading from the oil suction
screen located in the sump. The oil from the pump then enters a drilled passage in the
accessory housing which feeds the oil to a threaded connection on the rear face of the
accessory housing, where a flexible line leads the oil to the external oil cooler. Pressure oil
from the cooler returns to a second threaded connection on the accessory housing from
which point a drilled passage conducts the oil to the oil pressure filter. In the event that cold
oil or an obstruction should restrict the oil flow to the cooler, an oil cooler bypass valve is
provided to pass the oil directly from the oil pump to the oil pressure filter.
The oil filter element, located on the accessory housing, provides a means of filtering
from the oil any solid particles that may have passed through the suction screen in the
sump. After being filtered, the oil is fed through a drilled passage to the oil pressure relief
valve, located in the upper right side of the crankcase in front of the accessory housing. This
relief valve regulates the engine oil pressure by allowing excessive oil to return to the sump,
while the balance of the pressure oil is fed to the main oil gallery in the right half of the
crankcase. Residual oil is returned by gravity to the sump, where after passing through a
screen it is again circulated through the engine.
8B-3. TROUBLESHOOTING. Troubles peculiar to the power plant are listed in Table
VIIIB-III in the back of this section, along with their probable causes and suggested
remedies. Additional troubles peculiar to the power plant and the turbocharger are listed in
Table VIII-II in the back of Section VIII. Use Table VIIIB-III in conjunction with Table
VIIi-II. When troubleshooting
engines, ground the magneto primary circuit before
performing any checks on the ignition system.
8B-4. ENGINE COWLING. (Refer to Engine Cowling, Section VIII.)
8B-5. ENGINE COWL FLAP. (Refer to Engine Cowl Flap, Section VIII.)
8B-6. PROPELLER. (Refer to Table VIIIB-I and Propeller, Section VIII.)
8B-7. PROPELLER GOVERNOR. (Refer to Propeller Governor, Section VIII.)
Reissued: 10/12/79
POWER PLANT
2K20