Technical information

AUTOTRONIC CONTROLS CORPORATION • 1490 HENRY BRENNAN, EL PASO, TEXAS 79936 • [phone] • FAX [phone]
www.msdignition.com email: [e-mail]
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Distributor Setup
MSD offers a variety of distributors designed for dif-
ferent applications ranging from low profile and small
diameter models to a front drive distributor. You can
have the most powerful ignition available, but if you
are not accurately triggering all of that energy or not
getting it to the right spark plug at the precise moment,
all of that power is being wasted. Due to the increased
energy output of an MSD Ignition Control, proper setup
of the distributor is very important. A good quality cap
and rotor should always be used and inspected on a
regular basis. Note that areas with higher humidity are
more succeptible to carbon tracking or spark scatter due
to condensation build up. Another problem that can
arise within a distributor cap is called ionization.
Ionization occurs when the air inside the cap
becomes electrically charged resulting in spark scatter
or crossfire. It is more prevalent in smaller caps and
again in areas with higher humidity. MSD rotors are
designed with high vanes to help stir up the air
preventing a charged area from building up. For more
prevention, you can drill vent holes in the cap to re-
lease the pressure and to introduce fresh air. The holes
should be at the height of the rotor skirt and at least 1/4"
in diameter. Also, position the holes opposite the
intake manifold and in dusty climates, it is a good idea
to epoxy screens over the holes. MSD offers a pre-drilled
cap for V8 GM “window” style caps, PN 8438.
If clearance is not an issue on your application, use
as large as cap as possible such as the MSD Cap-A-
Dapt, PN 8420 and PN 8445 or the Pro-Cap, PN 7445.
Magnetic Pickup Wires
MSD Distributors use a magnetic pickup to trigger
the ignition. This pickup is maintenance-free and
extremely reliable. There are two wires that come out
of the pickup and are routed into a 2-pin connector
that mates with the connector from the MSD Ignition.
The Black/Violet wire is negative (-) while the Black/
Orange is postive (+). The wires that come out of the
MSD are Violet(+) and Green (-). The 2-Pin connec-
tors are designed to only connect one way so the wir-
ing cannot be switched. If for some reason the connec-
tors are changed, be sure the wires are connected with
matching polarity. If they are not, the engine may or
may not start, but if it does the timing will be inconsis-
tent and it will run rough and not accelerate.
The magnetic pickup wires should always be routed
clear of the spark plug wires and coil wires. It is ideal to
route the wires near the frame or engine because there
is less electrical activity near these surfaces. The wires
should always be twisted to help prevent any EMI
interference. In applications with a lot of wiring such
as electrical fuel injection systems, a shielded harness
is recommended. MSD offers a shielded magnetic
pickup harness, PN 8862, that ensures an EMI-free trig-
ger signal to the MSD Ignition.
DISTRIBUTOR SETUP TIPS