Piper APACHE PA-23-235 Service Manual page 1168

PIPER AZTEC SERVICE MANUAL
3. The ground electrode can be bent to obtain the required gap.
Method III:
1. Fabricate or purchase from Piper, the special tool from dimensions given in Figure
13-44.
2. Install the threaded end of the tool into the spark plug hole.
3. Slide the rod of the tool into the combustion head until it contacts the ground
electrode.
4. Check that the indicator ring on the rod lines up with the end of the tool. The
ground electrode may be bent to obtain the required gap.
NOTE
Inspect the ground electrode for erosion. If it is eroded to
approximately half of its original 1/8 inch diameter, it should
be replaced. This can be done as follows:
(a) Grind off the head of the rivet where it projects through
the combustion head and remove the electrode.
(b) Install a new CRES rivet AN125452 which is 1.500
inches in length.
(c) Heliarc tack weld the rivet head to hold it in place.
(d) Check spark gap as noted in Methods I, II or III.
d. Installation:
1. If a new spark plug is being installed, be sure to adjust the spark gap as outlined
in step c. Do not bend the electrode on the spark plug.
2. Place a new spark plug gasket on the threads. A small drop of Aviation
Permatex, or similar material may be used on the gasket to help hold it to the spark plug
shell during installation.
3. Screw the spark plug into the heater with a deep socket wrench. Tighten to a
torque of 28 foot-pounds. Install the grommet in heater jacket opening.
4. Carefully insert the spring connector on the high voltage lead into the spark plug
shell; press down gently and start the nut on the threads. Tighten the nut to 20 foot-pounds.
5. Operate the heater to check dependability and replace the access panels.
HEATING AND VENTILATING SYSTEM
Revised: 4/26/83
5G14