Piper PA-24 Comanche Service Manual page 400

PIPER COMANCHE SERVICE MANUAL
SEC1'IONVlIB
POWiR PLANT PA-Z4oooM)O
1B-1. ImrodUClioD. This section
COftrI
power plana ued in die
PA-2~
and is comprised of
insa'\lc:tions for the mnO¥l1. minor
repair.
scmcc
Uld
_,II",j
o
ft
of the enrine cowlial. propeller.
propeller ,ovemor. ftlJiAe.
en,iDe shock mounU. inducDon sysmn. ipiaoft system &ad lubrication system.
71-2. Dacripdoa. The PA·2+400 COmaDche
is
powered
by an Avco-Lycominl 10-120 AlA eiBht
cylinder. direct drive.
Wet
sump. fuel injected. horiJonully oppoMd. air-cooled ename with
a
compression
ratio of 8.1:1 raced at 400 HP at 2650 RPM and daipcd
to
operate Ob 1001130 (minimum) octane
aviation
Jftdc
fuel. Cowliq completely endotcS the ename aad consists of an upper. a lower. and a nose
see:tiOb. Side pandl Uft up to allow aCCaI to the CftJiae.
The propeller
is
a COnstlDt speed three blade HanzeU umt contrOlled. by a IOvenlor mounted on the
cnJine supplyU1B oil
duo.
the propeUcr
shaft
If
vuious pressutcS. Oil preuure from the governor moves
the blades into hiBh pitch (reduced RPM) and centrifupl
twistint
momcftt of the blades tend to move them
into low pitcll (hip RPM) in the aDlence of .00000r oil pressure.
The induction system consisa of a dry type air ruter. an alternate air door IIld a Bendix RSA·IOADI
type fuel injector. Tbis cnpne is nonna11y aspirated widlllO ratriC1ions on maximum power output.
Bendix Scinrill& 5-100 series
mapftOS
are inRal1cd with their usociated components. The m&fneto
SYStCDl consisu of a dual
(mud)
conUC't uxmbly
rnqncto.
a sialie contact assembly mapeto. a high
tension hunCSl assembly. one tnDSfonncr ISICmbly mounted on each m&fDeto and
twO
low tCDsion leads. ,\
statting vibrator. and a combination ipitioa and saner switch.
In Idc1ition to the previously mentioned componena. eacb enpoe is furnished with all-volt suner; a
10-ampere a1tcmator. a vacuum pump drive and fuel pump.
The lubrication system is of the prellUft
Wet
swnp type. The oil pump. which is located in the
accessory housm,. draws oil
through
a clriJlcd pusqe lcadin, from the oil suction screen located
in
the
sump. The oil from the pump then eQters a clriJlcd puaqe in the acensory housinl. whicll feeds the oil to a
threaded connection on the rear face of the accalOry housinJ. where a fle:tible line leads the oil to the
eXtCma1 oil cooler. Preuure oil from the cooler tctuml to
I
second threaded connection on the accessory
housinc from which point
I
drilled PUNIC conductS oil to the oil pfCssurescreen or mtet. In the CVCftt thac
cold oil or an obstruc:iion should rcmiet the oil flow to the cooler. an oil by-p.... valve is provided to pUi
the oil directly from the oil pump
to
the oil presaure screen or
fI1ter.
The oil pressure
saecD
or film clement, 10Qted on the accessory housitll is provided u a means to
filter from the oil any solid particles that may have passed throu,h the suction screen in the sump. Aiter
being filtered
in
the prasutc screen or filter. the oil is fed throulb a drilled P&SUIe to the oil pressure relief
valve. located
in
the upper right side of the cn.nkcasc in front of the accessory housiftl.
This relief valve regulates the enpne oil pressure by allowinl excessive oil to return to the sump. whtic
the balance of the prcuure oil is fed to the main oil
pUcry
in
the n,ht half of the aankcase.
Residu~
oil
LS
returned by gravity to the sump where, after PusU1l through a screen. it
is
a,1in
circulated through the
engine.
POWER PLANT
ISSUED: II18n2
2
E20
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