<VV> Mortal Coil

[Andy Clark]

Interesting perspective. I'm using the Pertronix (not the "II"), so my
experience is limited to that one.

If you read all of the Pertronix instructions, they say that the unit needs
12V. It also says that if you leave the ignition switch on, the coil may
overheat, and the Pert may be damaged. And BTW, there IS current flow
through a Hall Effect transistor when power is applied to it, even if the
trigger magnets are not rotating.

So, the need for 8V at the coil when running is still valid, even with the
Pert installed. This voltage takes into account the 50% duty cycle.

Yes, Pert the instructions do say to connect the 12V prior to the resistor
wire. While this provides 12V to the Pert when the ignition switch is in the
"run" position, it does not when going to "start". If you look at the
Corvair wiring diagram(s), connecting the Pert red wire at this point
results in about 8V to the Pert when starting, just when you particularly
need the full 12V. This results because the Pert is getting it's voltage
back-fed through the resistor when cranking. That's why one needs a relay to
provide 12V to the Pert under cranking and running conditions. Note the
cautions about "low voltage" in the Pert instructions.

Andy Clark
1966 140/4 Monza Sedan
1966 140/4 Yenko Clone
1966 180/4 Cord 8/10 #60
----- Original Message ----- 
From: "Padgett" <pp2 at 6007.us>
To: <virtualvairs at corvair.org>
Sent: Wednesday, April 19, 2006 8:17 AM
Subject: Re: <VV> Mortal Coil



>A standard coil is designed to work on about 8V. That's the reason for the
>resistor- it drops the voltage with the ignition switch in the "run"
>position.
>
>Unless you are using a coil that is specifically designed to run on the
full
>12V, a standard coil will overheat and ultimately fail. It's OK to put 12V
>on a standard coil for starting,

Hokay folks. The reason the coil is designed for 8V is so when the voltage
is drawn down by the starter during a cold start it will still have a good
spark. The resistor is bypassed when the starter is engaged.

The problem is that people would leave the key on (for the radio) with the
points closed and the engine stopped. This would flow current through the
coil constantly and needed to be controlled, when running the coil is
flowing half current or less. (30 degrees of dwell is a 50% duty cycle).

Now with a reflector-fed (magnet thingie) transistor ignition, if the
distributer shaft is not rotating, there is no flow through the coil.

Pertronics says different things about the Ignitor and the Ignitor II (I
have the II)

Ignitor: "First, if you have an external ballast resistor, connect the red
IgnitorT wire to the ignition wire
prior to the ballast resistor"
Ignitor II: "Many vehicles came equipped with ballast resistors or
resistance wires. To
achieve optimum performance we recommended removal of these
components."
(from support documents on http://pertronix.com )

I did have some issue with a hot (175F) running coil until I blocked the
opening in the shroud under the coil. Now it runs about the same as
compartment air temperature (also replaced the standard coil with a .6 ohm
Pertronix FlameThrower II).

So whether to keep the ballast wire/resistor depends on which Ignitor you
have. YMMV. Notary Sojac.

Padgett