Mallory Ignition Mallory DISTRIBUTOR А557 - Manual (Page 2)

www.mallory-ignition.com MALLORY IGNITION 2
Modes” instruction below.
10. Install the top cover using the two supplied hex
head screws. We recommend using a drop of blue
threadlock to prevent the standoffs from vibrating
loose.
11. Route the wiring harness between the pushrod
tubes and the cylinders and up to the coil. Try to
keep the harness away from the hot cylinder fins.
Connect the wires as indicated in the attached
“single fire/dual fire” wiring diagrams (page 4-5)
12. The timing should now be close enough to start the
engine. If not, loosen the distributor clamp and turn
the distributor slightly in either direction until the
engine starts. Once the engine has warmed up, the
timing can be set with a timing light. Adjustment to
the timing can be made by loosening the distributor
clamp and rotating the entire distributor. If neces-
sary, the entire distributor can be removed and
rotated one gear tooth to allow the wiring harness to
run between the pushrod tubes and cylinders. For
additional timing information see pages 3.
OPERATING MODES
A single 10 position rotary switch is used to select the
operating mode. Switch settings are as follows:
0 Street advance curves, dual fire, multi-spark dis-
abled
1 Street advance curves, dual fire, multi-spark enabled
2 Street advance curves, single fire, multi-spark
disabled
3 Street advance curves, single fire, multi-spark
enabled
4 Race advance curves, dual fire, multi-spark disabled
5 Race advance curves, dual fire, multi-spark enabled
6 Race advance curves, single fire, multi-spark dis-
abled
7 Race advance curves, single fire, multi-spark
enabled
8 Not used
9 Not used
The engine will not run if the mode switch setting
does not match the wiring hookup (i.e. you cannot
select single fire mode with a dual fire coil hookup).
Advance curve families are shown in Figures 6 and
7. Use the street advance curves (mode switch settings
0-3) for stock or mildly modified engines. Use the race
advance curves (mode switch settings 4-7) for high
compression engines.
We recommend that you enable multi-spark. When
multi-spark is enabled, a continuous series of sparks
is fired from the advanced timing point until TDC. Most
air-cooled engines require relatively cold spark plugs
to prevent detonation under high load. Multi-spark
reduces the consequent tendency for plug fouling at
idle.
Figure 2
Figure 3
CAUTION: Engine damage from
excessive timing advance may
result if the purple/white VOES wire
is inadvertently shorted to ground.