Piper Comanche PA-24 Service Manual page 575

PIPER COMANCHE SERVICE MANliAL
abo Time magnetos to engine I Refer to paragraph 7C -53 )
ac In'tall cowling I Refer to paragraph 7C-7)
ad Connect batter .. eTound cable. turn fuel selector \ahe on. open throttle full and tum on the
auxiliar~
fuel pump Check for
fuel·le~ks
7C-20a Protection Of Engine Mount. The lower engine mount tubes which are next to the turbochargers ha'e been
painted with a special heat resistant paint Should the mount need repainting. the following procedure must be followed
to insure the heat resistant quality - -
a Strip all old paint from the lower engine mount tubes
b Sand the full length of the tube, and remove all grease and oil
c Apply three brush coats of extra high H-170 Heat Rem paint or Krylon high heat aluminum paint
"0. 1402. or Randolph products heat resistant coating 1'\0 K3760 or 3761
"OTE
The engine mount tubes should be warm during the paint application.
but not hot
d Alloy, twehe hours between brush coats
7C -21 Engine Shock Mounts. Replace engine shock mounts Refer to Figure 7C -4 for the proper arrangement of
engine shock mount assemblies Place shock mount with P "J-3049-35 in the top front position and shock mount" ith
P " J-3049-14 '" the bolt om front position Place shock mount with P "J-3049-34 in the top rear position and shock
mount with P " J-3049-35 in the bolt om rear position Torque shock mount bolts to 450 to 500 in Ib, with torque
wrench applied
to
bolt heads and safe"
7C-22 Turbocharger.
7C -:!::!A Turbocharger Nomendature. Many unfamiliar terms may appear on the following pages of this manual An
understanding: of
tht:s~
"ill be helpful.
if
not
necessar~.
in performing maintenance and
trouble~hooting
The following
is a list of commonly used terms and names as applied to turbocharging and a brief description
TERM
Supercharge
Superchargc:r
T urbo->iupercharger
Compre ...... or
Turbine
\\"astegate and Actuator
(E:w.hau~1 B~-Pas:-..)
REVISED: 4/10/81
To increase the air pressure (density) above or higher than amblent"conditions
A de\"ice that accomplishes the increase in pressure
More commonly referred to as a "Turbocharger" this device is dri\"en by a turbine
The turbine is spun by energy extracted from the engine exhaust gas
The portion of a turbocharger that tak.es in ambient air and compresses it before
discharging it to the engine
The exhau,t dri\en end of the turbocharger unit
The wastegate is a butlerfly type \"al\"e in the exhaust by-pass \\ohich. throughout its
irani from open to
c1o~ed.
allows \aried amounts of exhaust gas to by-pas.s the
turbin. controlling its speed. hence the output of the compressor The actuator
i~
operated by a hydraulic piston operated by engine oil and cylinder with the piston
linked to an arm on the butterfly \"alve shaft.
2G19
POWER PLAII'T