DISCLAIMER: Specifics are for a '64
Riviera. There are slight differences in the wiring between the
Riviera and other full-size Buicks, and there may be differences
between model years. Double check this information against the wiring
diagram for your car before doing something you may regret,
particularly with regard to wire colors and terminal numbers.
If you want to install a
Pertronix system in your car,
you should be aware that the voltage at the ignition coil is limited
to ~ 9V while the car is running. This is done to minimize the
pitting that would normally occur at the points. The voltage is
lowered by running the current to the coil through a resistance wire
that is in the circuit between the ignition switch and the coil.
The start and run circuits on a '64
Riviera are different. When the key is in the start position, the
resistance wire is bypassed, which provides 12V to the coil/points.
This is done via the yellow wire from the starter. If you trace it
back to the firewall connector, you will notice that it connects to
the pink wire that runs to the coil. This brings us to a common
misconception: the pink wire is *not* resistance wire; it's just
standard 16 gauge wire. The resistance wire runs from the ignition
switch to the firewall connector inside the dash harness. In the
wiring diagrams it is listed as W.O.P.C.T. (white with orange and
purple cross tracer (res. wire 1.8 ohms.)).
When in the start position, the current
to the coil runs from the battery to the ignition switch (red wire),
to the starter (purple wire; via the neutral safety switch at the
console shift lever), to the firewall connector (yellow wire), to the
coil (pink wire). By bypassing the resistance wire, you get the full
12 V at the coil.
In the run position, the current to the
coil runs from the battery to the ignition switch (red wire), to the
firewall connector (resistance wire), to the coil (pink wire). Routing
the current through the resistance wire knocks the coil voltage down
to ~8.5 V.
Note that all of this may be moot. I
called Pertronix about the installation in my '64 Riviera to ask about
this, as I get 8.5 V at the coil with the engine running. I wanted to
know if I had to run a new wire to get 12 V to the Pertronix module
and/or coil. I was told that both will work at 7.5+ V. This means that
even with the resistance wire in place, you should run just fine
tapping off the coil terminal.
If you absolutely have to have 12 V at
the coil/points before you can sleep at night, you have a couple of
- You can either replace the
resistance wire from the ignition switch to the firewall connector
or run another wire in parallel. If you chose to run a second wire,
it will effectively negate the resistance wire. The advantage of
running a wire in parallel is that you can return to the stock set
setup (in case you want to return to points) with a simple snip of
the new wire. It's also cleaner; no one will ever see your
modifications. The disadvantage of this idea is the pain in the butt
factor. All of this work takes place under the dash (with you on
your back), and requires you to pull your ignition switch and maybe
the firewall connector so you can get to the appropriate terminals
to make your connections. However, you can avoid pulling the switch
and connector by using the wire taps described at the end. In this
case, you would bypass the resistance wire by tapping it at both
resistance wire (in dash harness)
firewall |--/\/\/\/\/\/\/\/\/--| ign switch
- If you want to do this all under the
hood, you can tap terminal 4 (brown wire) of the voltage regulator.
It is hooked up to IGN terminal of the ignition switch, and, once
the car is running, it draws 12V directly from the battery.
When tapping wires, I recommend using
the quick-connect wire taps (e.g. Radio Shack
part # 64-3052 (Tap-In Squeeze Connectors for 18 to 14-gauge
wire)). They work by piercing the insulation, and require no
stripping, soldering, or anything else; you simply squeeze them
thanks to John Chapman for his contributions.