MSD 8584 Ford V8 351W Billet Distributor Tech Bulletin - Manual

T ech Bulletin
MSD’s Tech Bulletins are designed to give you a more
in-depth understanding of the ignition system and its components. If you have any other
questions about the subject or MSD products you can contact our Customer Support Depart-
ment at (915) 855-7123.
Every ignition system requires a trigger signal to accurately fire and deliver a high voltage spark from the coil. There
are several ways this is achieved, from mechanical breaker points to magnetic pickups, optical triggers and other elec-
tronic switches which all serve the same function; to accurately trigger the ignition at the correct moment for the ideal
spark timing.
MSD incorporates a magnetic pickup in our distributors because of their reliability and accuracy. In fact, most major
automotive manufacturers used magnetic pickups in their distributors until the advent of distributorless ignition systems
in late model vehicles. (For MSD’s Flying Magnet Crank Trigger systems, a non-magnetic pickup is used. This pickup
functions in a similar manner as the magnetic pickup which will be explained below.)
This bulletin provides an explanation as to the operation of a magnetic pickup and non-magnetic pickup, their polarity
and testing along with a few helpful installation tips.
Secrets to Successfully
Using an MSD Magnetic and
Non-Magnetic Pickup
Figure 2 - MSD Flying Magnet Crank Trigger.
Theory – How Does It Work?
The magnetic pickup is actually a wire that is wound
around a magnet to create a magnetic field. Whenever
this field changes, due to another metal object coming into
the field, a voltage is generated. MSD uses this voltage
as a trigger signal for the ignition control.
An MSD Distributor incorporates a metal reluctor wheel
with eight evenly spaced trigger tabs (six for 6-cylinder
engines, four on 4-cylinders). This reluctor is mounted
to the distributor shaft (Figure1). Each time one of these
reluctor tabs passes the magnetic pickup, a trigger signal
is created which fires the MSD Ignition.
Conversely, an MSD Flying Magnet Crank Trigger system
uses a non-magnetic pickup. The pickup consists of a wire
that is wound around an iron core rather than a magnet.
To create the voltage for the trigger signal, a magnet must
pass the pickup rather than a metal post (Figure 2). MSD
uses this design because we have the capability to install
magnets in a crankshaft mounted wheel and the pickup
cannot be triggered by anything other than the magnet
so there are no chances of false triggering.
Though these two pickups require different trigger
sources, they essentially function in the same manner
and share the same wiring and installation tips.
Figure 1 - MSD Pro-Billet Distributor.
RELUCTOR
TRIGGER TABS
MAGNETIC
PICKUP
TRIGGER
MAGNET
NON-MAGNETIC
PICKUP
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