Page 8 - NM Spring_2021

utilize a set of magnetic pickups
rather than points. In addition, MSD
magnetos utilize a pair of power
transistors in a separate “points
box” to switch the current instead of
actual points. The magnetic pickup
is required only to create the signal
telling the transistors to fire.

The downside to each involves
when it becomes time to retard
your ignition timing in order to
transverse a race track. At instances
on the track where traction could
become difficult, teams often
choose to retard the ignition
timing to kill off some horsepower.
In order to do that requires the
points which are mounted to the
distributor be moved. You can’t
easily do that with a points style
mag, although as Miller pointed
out, “To accomplish that with a
points mag requires the magneto Regardless of what style of ignition system you use, replacing the coil wire from time to
to actually be moved since the time is imperative as it fires eight times more than any single spark plug wire.

points that trigger the ignition are Cars and some classes of race boats
inside. Mag drives with pneumatic for example, use their mags in a
actuation can be employed in this constant duty type of application,”
case.” adds Miller. “A giant magneto
on an engine running for a long
Using a magnetic pickup period of time would overheat and
allows one to utilize an additional fail. Modestly powered mags that
electronic box such as MSD’s are plenty adequate for naturally
Power Grid to advance and retard aspirated methanol or even
timing as the racer sees fit, within supercharged methanol applications
reason.
are perfect for those situations.
“The question we often get Drag racing or intermittent duty
asked,” says Miller, “do I need applications seeing very high boost
a magneto which puts out more or nitromethane will require a
amperage to the spark plugs? The larger mag to get the spark across
short answer is that it depends the gap.
entirely on your combination. “But if you’re looking for
Boost, compression ratio and fuel simplicity, a fairly standard mag
type determine cylinder pressure with points might be the answer,”
and ultimately, how much ignition Miller adds. “For people that don’t
power is required to meet the need.
It’s all about generating electricity to need all the bells and whistles
the spark plugs, something a mag is “Magneto users such as Sprint
very good at creating. Continued on page 11
8 Nitro Madness Magazine SPRING 2021