Rockwell Commander 112 - OIL SYSTEM

SECTION IV
POWER PLANT
AND PROPELLER
MAINTENANCE MANUAL
ROCKWELL
COMMANDER
112/B/TC/TCA
through a drilled passage leading from the oil filter
located in the sump. Mter passing through the pump,
oil flows through a drilled passage in the engine and
then through a line to the oil cooler. Oil pressure
from the cooler is returned to the accessory housing
where it is directed through the oil filter, contained
in a cast chamber mounted on the accessory housing.
If cold oil or an obstruction should restrict oil flow
through the cooler, an oil cooler bypass valve will
route the oil directly from the oil pump to the oil fil-
ter. The oil is then filtered through the oil filter
chamber and fed through a drilled passage to the oil
pressure relief valve, located in the upper right side
of the crankcase forward of the accessory housing.
This relief valve regulates the engine oil pressure by
allowing excess oil to return to the sump, while the
balance of the oil is fed to the main oil gallery in the
right half of the crankcase. Oil is distributed from
the main gallery, by means of separate drilled pass-
ages to each main bearing of the crankshaft. The
drilled passages to the bearings are located in such
a manner as to form an inertia type filter, thus en-
suring that only the cleanest oil will reach the bear-
ings. Drilled passages from the rear main bearing
supply oil pressure to the crankshaft idler gears.
Angular holes are drilled through the main bearings
to the rod journals where sludge removal tubes are
located. Oil from the main gallery also flows to the
cam and valve gear passages, and is then conducted
through branch passages to the hydraulic tappets and
camshaft bearings. Oil travels out through the hollow
push rods to the valve rocker bearings and valve
stems. Oil from the bearings, accessory drives and
rocker boxes returns to the sump by gravity flow,
passes through the inlet oil screen and is then re-
circulated through the engine. Refer to Section II
for oil system servicing.
OIL COOLER
MODELS 112/B. The cooler is installed on the right
forward side of engine firewall and receives its
cooling air from the engine nacelle compartment. Oil
under pressure from the engine enters the inboard side
of the cooler, passes through the cooler and back to
the engine. A thermostatically operated oil cooler
bypass valve causes oil to bypass the cooler in the
event of congealed oil or an obstruction in the cooler.
This bypass valve also routes oil directly to the suction
screen until a predetermined oil temperature is reached.
The oil is then routed through the cooler.
MODELS 112TC/TCA. The cooler is installed on the
left forward side of engine firewall and receives its
cooling air from the engine nacelle external scoop.
Oil under pressure from the engine enters the inboard
side of the cooler, passes through the cooler and
back to the engine. A thermostatically operated oil
cooler bypass valve causes oil to bypass the cooler in
the event of congealed oil or an obstruction in the
cooler. This bypass valve also routes oil directly
to the suction screen until a predetermined oil tem-
perature is reached. The oil is then routed through
the cooler.
4-12
OIL SCREEN AND FILTER
MODELS ll2/B. Clean engine oil is assured by the
use of one oil suction screen and one oil filter for the
engine. The oil suction screen is located in the right
side of the oil sump and the oil filter is located in a
casting, bolted to the accessory housing between the
magnetos. Use of this screen and filter provides dual
protection for positive screening of damaging foreign
material from the oil. The oil pump draws oil from
the sump through the suction screen and pumps it
through the oil cooler to the engine. Oil screen and
filter must be cleaned each time the oil is changed
or whenever improper oil circulation is suspected.
Servicing instructions are provided in Section II.
MODELS 112TC/TCA. Clean engine oil is assured by
the use of one oil suction sc reen and one oil filter for
the engine. The oil suction screen is located on the
right side of the oil sump and the oil filter is located
in the accessory housing on the right side of the en-
gine. Use of this screen and filter provides dual pro-
tection for positive screening of damaging foreign
material from the oil. The oil pump draws oil from
the sump through the suction screen and pumps it
through the oil cooler to the engine. Oil screen and
filter must be cleaned each time the oil is changed or
whenever improper oil circulation is suspected.
Servicing instructions are provided in Section II.
ENGINE OIL
MINERAL
(MIL-
L-6082B)
SAE 50
SAE 40
SAE 30
SAE 20
ASHLESS DISPERSANT
(MIL-L-22851)
SAE 50 or 60
SAE
50
SAE 40
SAE 30
AMBIENT AIR TEMP.
Above 60
0
F
30
0
to gOOF
0
0
to 70
0
F
Below lOoF
AMBIENT AIR TEMP.
Above 60
0
F
30
0
to gOOF
0
0
to 70
0
F
Below lOoF
NOTE
To promote faster seating and improved
oil control, the Models 112/B were
delivered from the factory with a mineral-
type (non-detergent) oil installed. This
break-in oil should be used for the first
50 hours only, at which time it must be
drained and replaced with detergent oiL
Mter the first 25 hours of operation, drain engine oil,
clean suction and oil filter screens and replace filter
element. Refill the sump with non-detergent oil and
use until the 50 hour mark is reached or oil consump-
tion has stabilized, then change to detergent oil con-
forming to previous specifications.
Change 3
I
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**unofficial copy**