12 v ignition power source for pertronix

[tsa]

I installed a Pertronix II and Flame Thrower into my 67 using the original wiring. The timing was all over the show, it would go from advanced to nothing to something else on different startups. You couldn't time the car at all. Pulled it all out and put the points back in.

Contacted Pertronix as I thought I had a dud unit and they said make sure it has 12V supply. Have never got around to testing again. Anyone else seen this sort of thing or is my unit actually dud?

[2sasilverbullet]

I would hook it all back up with the dedicated +12v source and see what happens. I spent many hours talking to Pertonix tech support about other issues, and the guy warned me to make sure it was connected to a dedicated +12v source or "weird things" would happen.

[Dan Szwarc]

My 66 has been running a pertronix 1 system since 1999 and I have had zero problems. When I switched to 12v instead of the power at the coil it ran smoother at idle.

[autostick]

Same experience as Dan, except I have a Pertronix 2, and it was only a year or two at 9 volts. I will also point out I have NGK iridium spark plugs gapped wider than spec, as the plugs are the rate limiting or weak spot once you install a good coil and Pertronix. Of course it assumes you have good wires as well.

[Solid]

FWIW, I finally got around to dealing with this myself today. I tapped 12V at the battery and stuck a relay to the side of the battery box. I am using the ~9-10V source from the resistor wire to trigger a 30A relay (I tested this for about 50 cycles and it worked every time). Prior to doing that though, I started the car with a jumper attached to the positive terminal on the coil (I am using a Flamethrower coil with the Pertronix III) and tested to see whether the idle changed with and without the 12V jumper. It is immediately obvious when the 12V source is in place, as the idle smooths out and periodic misses disappear. They came back every time I removed the jumper, and went away again every time I reattached it, across multiple cycles.

[2sasilverbullet]

FWIW, I finally got around to dealing with this myself today. I tapped 12V at the battery and stuck a relay to the side of the battery box. I am using the ~9-10V source from the resistor wire to trigger a 30A relay (I tested this for about 50 cycles and it worked every time). Prior to doing that though, I started the car with a jumper attached to the positive terminal on the coil (I am using a Flamethrower coil with the Pertronix III) and tested to see whether the idle changed with and without the 12V jumper. It is immediately obvious when the 12V source is in place, as the idle smooths out and periodic misses disappear. They came back every time I removed the jumper, and went away again every time I reattached it, across multiple cycles.

Wow! Thanks for doing the research to confirm this.

[denizen44]

Also in the same boat with a newly acquired Pertronix II.

Edited part:
I do have the brown/pink resistor wire combo going to the original coil, which I intend to use.
Apparently the purpose of the resistor wire is to drop the coil voltage slightly during operation, to avoid overheat:

The wire needs to go to two places. It leaves the coil and then splits. The brown wire goes down to the starter motor solenoid. When you have the starter going, the solenoid sends full 12 volts to the coil to cause a 'hot' spark. The other wire, which is pink goes to a resistor and then to the ignition switch 'run' position. This is the position the ignition is in when the car is 'running' after it has started. The purpose of the resistor is to drop the voltage that now goes to the coil so the coil dosen't overheat from too much current flowing thru it. The voltage now should be about 8 -9 volts if you measured it with a voltmeter between the coil and a good ground.

[Dan Szwarc]

I don't think the coils overheat with a pertronix because of the way the Hall Effect sensor works.

On a points system, the points are closed and conducting current 90% of the time. The spark occurs when the points OPEN, which is the peak of each point on the distributor cam.

The Pertronix might only be closed for a small portion when the magnet is near the unit, then jumps to off when it falls away. This would mean it spends more time OFF than ON. Since it still sparks when the unit turns OFF (opens), the coils it not actually conducting current as much compared to using points.

Someone from pertronix could confirm this or someone with a scope.

[denizen44]

Ok Dan, I've emailed their tech support.
In the meantime, if I choose to keep my coil's resistor wire,
the instructions seem to indicate that I could still install a switched 12v wire for the module only.
Is this how you installed yours?

[Dan Szwarc]

Hmmm. I'm not sure. i think I wired the 12V to the coil and Ignitor as in the left figure. That was a few years ago. I've driven over 5,000 miles since with the original coil and for great distances and durations (12hrs on the roads or more in a day).

[denizen44]

Well today alone I've found plenty of "overheating coil" stories when a full 12V was used on them...
Of course your personal results and Hall Effect sensor theory contradict this.
Then again, the involved setups were probably slightly different (not V8s ) but resistor wires were
often mentioned/bypassed. Anyone here check their coil temperature?

[brendanw]

Check my photo at the bottom of page 3 on the thread below. It's a similar approach that one of the guys took, mentioned on this thread here, page 2. Bottom line is that - assuming your running a new Ignitor coil - all you need is a constant 12V source to it. As you'll see in the thread I've linked, I installed a new fuse block under the hood, powered off of the stock ignition relay, and am now powering a few things off of it. Pertronix, electric carb choke, stereo, etc. All of the talk of resistors has just confused the rather simple installation in my opinion, but to each his own.

http://www.thelincolnforum.net/phpbb3/v ... 8&start=30

[denizen44]

Bottom line is that - assuming your running a new Ignitor coil - all you need is a constant 12V source to it. As you'll see in the thread I've linked, I installed a new fuse block under the hood, powered off of the stock ignition relay, and am now powering a few things off of it.

Well in my case I won't run a new Ignitor coil and I have no problems finding a switched 12V source,
my dilemma is whether or not I should also power my old coil with that source or just the pertronix unit.
Dan seems to have powered both with 12V, just like on the left schematic above,
whereas I may go for the separate 12V for the unit and a stock (lesser) voltage for the coil.
Which is why I asked if anybody whose got their stock coils on 12V checked the temp.

[66Lincoupe]

I have 12 volts running to my Pertonix flame thrower coil AND to the unit. The Pertronix coil is internal resistor so works best with a full 12 volt supply. The STOCK Ford coil is external resistor which means it needs a resistor to prevent overheating the primary winding.

Pertronix instruction manual: http://pertronix.com/docs/instruction-sheets/1141.pdf

Page 3 of the PDF (marked page 2 on the page itself) explains

[brendanw]

Well in my case I won't run a new Ignitor coil ...

Ok, got it. Now I understand your dilemma. Sounds like 66lincoupe has your answer. Unquantified relative to your "how hot does the coil get without a resistor, but a great answer nonetheless.

Seriously though, for the money the Ignitor coil is well worth it and looks perfectly (not an LCOC guy) stock. If it solves your quandary and gets you more spark, then it's worth it. Good luck!