Textron Cessna 172S Skyhawk SP, Information Manual

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CESSNA
MODEL 172S .
SECTION 7
AIRPLANE & SYSTEMS DESCRIPTION
The EGT system 'uses a thermocouple in the engine exhaust
(tailpipe) to supply a voltage proportional to exhaust gas
temperature. The 'EGT indicator responds to the voltage developed
by the thermocouple. As the mixture is leaned (from full rich), the
. exhaust gas temperature will increase to.a maximum value as the
stoichiometric (most chemically efficient) fuel-air ratio is achieved
and will decrease if the mixture continues to be leaned .
. NEW ENGINE BREAK.IN AND OPERATION
The engine underwent a run in at the factory and is ready for the
full range of use. It is, however, suggested that cruising be
accomplished at 75% power as much as practicable until a total of
50 hours' has accumulated or oil consumption has 'stabilized. 'This
will ensure proper seating of the piston rings.
ENGINE LUBRICATION SYSTEM.
The engine utilizes. a full-pressure. wet-sump type lubrication
system with aviation-grade oil used as the lubricant The capacity of
the engine sump (located on the bottom of the engine) is eight
quarts. Oil is drawn from the sump through an oil .suction strainer
screen into the engine-driven
oil pump. From the pump, oil is routed
to a bypass valve. If the oil.is cold, the bypass valve allows the oil to
bypass the oil cooler anq go directly from the pump
10 the full flow
oil filter. If the oil is hot, the bypass valve routes the oil out of the
accessory housing and into a flexible hose leading to the oil cooler
on the right. rear engine baffle. Pressure oil from the cooler returns
to the. accessory housing where it passes through the full flow oil
filter. The filter oil' then enters a pressure relief valve which
regulates engine oil pressure by allowing excessive oil to return to
the sump while the balance of the oil is circulated to various engine
parts for lubrication. Residual oil is returned to the sump by gravity
flow.
An oil filler cap/oil dipstick is localed at the right rear of the
engine. The filler cap/ dipstick is accessible through an access door
on the top right side of the engine cowling. The engine should not
be operated on less than five quarts of oil. For extended flight. fill 10
eight quarts (dipSlick indication only). For engine oil grade and
specifications. refer to Section 8 of this handbook.
Revision 4
7-21