Piper PA-24 Comanche Service Manual page 472

PIPER COMANCHE SERVICE MANUAL
7C~1.
IlIIpCCIioaADd cJanj., Of Spule ......
a. Visu&Uy
i~eet
ach
spark plu. for the foUowiq non-l1!'?ainble defectS:
1.
Severely d&mqed shell
or
sbield mr.dIllicked up. stripped or crotIduuded.
Z. Badly baaered or rouadcd IbeJl bGllODS.
3. Out-of-round or
damapd
lbicldiDt bum!.
4.
Chipped.
cracked. or
brokal c:euUc
iDlulator pORioaa.
5. Badly
eroded
e1ee:a:oda
wom
to
approxUnate1y 5ow.
of
oriIiDa1
s~e.
b. Clean the spark plq
u
required.
removiaI
carbon
and foman deposits.
c.
Test tile spark plUl both dcetric:a11y IDd for resiRuc:e.
d.Set the dccaodc laP at .016
~.lofan
inch
orila _oomer
operation at idle speed and reduced
lftII1lcrD dropoGff
is
desire.
Sft
at .018 to .02%of an inch. Howeftf, with wide pp
sm:iDt
the plul'
must
be
serviced
at
more frequent iDtftVals. Fine wire pWinum or iridium
electrOdes should be
set
at .015 to .018
of
an
inch only.
7C-6Z. 1DIaUaGoa Of SpIIk
PIup.
Before
inIta1liDI
spark plup. UCCtUia thac the threads within the
cylinder arc daA and not damapd.
a. Apply anti1Cize compound spariDpy on the tIIrads and iDSa.ll psket and spark plup. Torque 360
to 42.0 incb pounds.
CAUTION
Make certain the deep socket
is
properly
_ted
on the spark plug
hexacon u
ctamace
to the pha, could result if the wreach is cocked to
one side
Whelll
preuute is applied.
b.
C~cfuUy
irlsert the tcrmiDal insulator in the spark plUllAd tiptcn the couplinS nut.
7C-63. Lubricadoa System.
7C~.
Oil Prcuure Relief Va1ft. Tbe adjusublf >i1 pressure relief valve enables the operator to mainuin
eftline oil pressure within the specified limits (refer to the eftJine lIWlufa.e:tUrCf's appropriate manual). The
valve is located above md to the rear of No, 5 c:ylilllder. If the presllUC under nonnal opcratina conditions
should consistently exceed 90 psi. or run less than 60 psi. adjust the valve u foUows:
With the elJline thorou.tl1y wumcd up md
rurminl
at a rnuimum of 2200
RP~,
obsefVC the readi"l
on the oil pressure pup. If the pressure is above 90 psi. stop enaine. back off the adjustinl screw one or
tWO
full turns. If pressure is too low,
t\ll1l
adjustin, screw further intO the relief valve pluS. thereby
increuinl the tension on the relief valve spring. When the valve
nu
been satisfaCtorily adjusted. lockwire
the crown nut to the drilled ear projec:tinJ from the valve mounan, bo•. The engine hu a thermostatic
bypus valve as
a
safety feacure. The valve
will
open should the temperaNre exceed a safe operating level
and allow the oil to circulate in the system to avoid permaneftt damaae to the engine.
POWER PLANT
ISSUED: 8/11/72
2
H20
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