New Engine Break- I N And Operation; Eng I Ne Lubrication System; Revision 4 - Cessna 172SPHUSR05 Pilot Operating Handbook

C ESSNA
MODEL 1 72S
The EGT system uses a thermocouple in the engine exh aust
(tai lpipe) to supply
temperature. Th e EGT i ndicator responds to the voltage developed
by the thermoco uple . As the m ixtu re is leaned (from full rich ) , the
exhaust gas temperatu re will i ncrease to a maxi m u m value as the
stoich iometric (most chemically efficient) fuel-air ratio is ach ieved
and will decrease if the mixtu re contin ues to be leaned .
N EW E N G I N E B R EA K- I N A N D O P ERATION
The engi ne u nderwent a run in at th e factory and is ready for the
full range of use. It is , however, suggested that cru ising be
accomplished at 75% power as m uch as practicable u nti l a total of
50 hours h as accum u lated or o i l consumption has stabilized . This
wi l l ensure proper seating of the piston rings.
E N G I N E L U B R ICATIO N SYSTE M
The engine utilizes a fu ll-pressure, wet-su m p type l ubri cation
system with avi ation-grade oil used as the lubricant. The capacity of
the engine s u mp (located on the bottom of the engine) is eight
q uarts . Oil is drawn from the sump th rough an oil suction strainer
screen i nto 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 and go d irectly fro m the pump to the ful l flow
oil filter. If the oil is hot, the bypass valve routes the oil out of th e
accessory housing and i nto 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 fu ll flow oil
fi lter. 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 l ubrication. Residual oil is returned to the sump by gravity
flow.
An oil fil ler cap/oil dipstick is located at the right rear of the
engine. The fil ler cap/ dipstick is accessible through an access door
on the top right side of the engi ne cowling. The engine sho u ld not
be operated on less than five quarts of oil. For extended flight, fi ll to
eight q uarts (dipstick i ndication only) . For engine oil grade and
specifications, refer to Section 8 of th is handbook.

Revision 4

AI RPLANE
a voltage proportional
&
SYSTEMS DESC R I PTION
to exhaust
S ECTION
gas
7-2 1