45
AeroVee 2.1
Rev Z. 01/14/2015
Sonex Aircraft
LLC
© 2014 All Rights Reserved
ELECTRONIC IGNITION TIMING
Tools Required
__ 5/32" hex wrench
Timing Basics
The electronic (secondary) ignition is timed to match the
Magnatron (primary) ignition, which is fixed at 28 degrees
BTDC. Accurate timing is accomplished when the two igni-
tion systems are firing as one, which is indicated by little or no
difference in engine RPM when switching between ignition
systems.
The trigger cap (A) of the secondary ignition system rotates to
make timing adjustments. It is locked in position by a socket
head cap screw (D). When the magnet in the trigger cap passes
by the sensor in the triggers (C), it fires the spark plugs. The
location of the magnet in the trigger cap is marked with a line
(B).
A
C
B
The trigger cap (A) is locked in position by a socket head cap
screw (D). A mark (B) on the trigger cap corresponds with the
location of the trigger magnet. When this magnet passes by
a sensor (C) in the upper and lower triggers, the spark plugs
fire.
D
Timing the Secondary Ignition
important: The secondary ignition will spark when the
ignition is on and the trigger magnet passes by the sensor.
This can cause ignition. Avoid serious injury or death by
turning off the fuel, ignition switch, and master switch and
remaining clear of the propeller while timing the ignition.
Initial timing is achieved by aligning the right edge of the
magnet shoe on the flywheel (E, photo below) with the right
edge of the top Magnatron (F) and then rotating the trigger cap
(A) until the mark on the cap (B, previous column) is centered
under the sensor (C) of the upper trigger. The following steps
detail this process.
The black / white line on the right shows how the top
Magnatron and magnet shoe on the flywheel align prior to set
-
ting the secondary ignition timing. For clarity these parts are
shown removed from the engine.
__ 1. Turn off the aircraft's Master switch, secondary ignition
switch and fuel valve.
__ 2. Pull the cockpit mixture control to "Idle Cut-off".
__ 3. Rotate the crank until the right edge of the magnet shoe
on the flywheel (E, above) is aligned with the right edge
of the top Magnatron (F, above). Look down between
the accessory plate and the rear flange of the engine
case to check the alignment of the top Magnatron to
magnet shoe on the flywheel.
F
E
