New Engine Break-In And Operation; Engine Oil System - Cessna SKYHAWK 1976 Pilot Operating Handbook

7-18
SECTION 7
CESSNA
AIRPLANE
&
SYSTEMS DESCRIPTIONS
MODEL 172M
markings indicate that minimum idling pressure is 25 PSI (red line), the
normal operating range is 60 to 90 PSI (green arc), and maximum pres­
sure is 100 PSI (red line).
Oil temperature is indicated by a gage adjacent to the oil pressure
gage. The gage is operated by an electrical-resistance type temperature
sensor which receives power from the airplane electrical system. Oil
temperature limitations are the normal operating range (green arc) which
is 38°C (lOO°F) to H8°C (245°F), and the maximum (red line) which is
118°C (245°F).
The engine-driven mechanical tachometer is located near the lower
portion of the instrument panel to the left of the pilot's control wheel.
The instrument is calibrated in increments of 100 RPM and indicates both
engine and propeller speed. An hour meter below the center
of
the tachom­
eter dial records elapsed engine time in hours and tenths. Instrument
markings include a normal operating range (stepped green arc)
of
2200 to
2700 RPM with steps at the 2500 and 2600 RPM indicator marks. The
normal operating range upper limit is 2500 RPM at sea level, and increas­
es to 2600 RPM at 5000 feet and 2700 RPM at 10,000 feet. Maximum (red
line) at any altitude is 2700 RPM.
A carburetor air temperature gage may be installed on the right side
of
the instrument panel to help detect carburetor icing conditions. The
gage is marked in 5° increments from -30"C to +30°C, and has a yellow
arc between -15°C and +5°C which indicates the temperature range most
conducive to icing in the carburetor. A placard on the lower half of the
gage face reads KEEP NEEDLE OUT OF YELLOW ARC DURING
POS­
SIBLE CARBURETOR ICING CONDITIONS.
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 65% to 75% power until a total of 50 hours has accumulated or oil con­
sumption has stabilized. This will ensure proper seating of the rings.
The airplane is delivered from the factory with corrosion preventive
oil in the engine. If, during the first 25 hours, oil must be added, use
only aviation grade straight mineral oil conforming to Specification No.
MIL- L-6082.
ENGINE OIL SYSTEM
Oil for engine lubrication is supplied from a sump on the bottom of
the engine. The capacity
of
the engine sump is eight quarts (one additional