I didnt do my home work

[CJ,s 67 F100]

I started my new 390 up with a Pertronixs Ignitor and a Pertronixs Flame ThrowerII coil using the resistor wire from my ign. Then I installed the Crane XRi ign. and used the Flame ThrowerII coil and the resistor wire from my ign. I wanted to use the rev limiter feature of the Crane XRi.
Then my coil blew a seal and of course it wouldnt run. Here is why it blew.
1. The Pertronixs Ignitor needs a full 12 volts from the ign. and a 1.5 ohm coil or ballast resistor
2. The Pertronixs Ignitor II needs a full 12 volts from the ign. and a 0.6 ohm coil or ballast resistor
3. The Crane XRi needs a full 12 volts from the ign. and a 1.2-1.9 ohm coil or ballast resistor
4. The Pertronixs Flame Thrower coil is a 1.5ohm internal resistance coil
5. The Pertronics Flame ThrowerII coil is a 0.6ohm internal resistancecoil To solve my problem I purchased a new Pertronixs Ignitor, a new Pertronixs Flame thrower coil and I ran a full 12 volt wire from the ign. to my coil +
I tied the new Pertronics Ignitor red wire to my coil +
I tied the new pertronixs Ignitor black wire to my coil -
I tied my tach to my coil -
This time and money could have been avoided if I,d done my home work first. I ran the new wire because I didnt like the condition of the resistor wire after I removed it from the sytem. I hope this saves someone from my mistake.

[68F250]

Sorry to hear of your problems.

But you made some good points. When changing to a high-output coil (low primary resistance) you have to consider two things. One, is the ballast resistor correct for the coil, and two, can the ignition system handle the current of the high-output coil?

I know the Pertronix I, Crane XRi and Mallory Unilite can't handle high-output coils. On your setup, you're close to the limit of what the Pertronix I can handle with the Flame Thrower coil hooked directly to 12 volts.

Glad you got it all sorted out!

[FORDification]

Good info! I saved that for future reference. Thanks Charles!

[Supermike]

Hey Charles,

I know this post goes back a ways, but trying to understand here... I don't plan to use a tach, but are you saying that if I install a Pertronix II and Flamethrower II coil in my '67, I'll need to run a new 12v wire from the ign. to my coil +, or risk blowing the coil??

Or does this only apply if you're wiring in a tach?

[kid]

The tach does not matter it draws almost no current and counts the pulses that fire the coil in an averaging circuit that is powered by the 12 volt going into the tach from your inside hot feed.

[lrjetmech]

I installed the Pertronix II and Flamethrower II coil in my truck. Removed the ballast resistor. Ran a new wire to the middle of my dash area from the solenoid. I then spliced on two wires to this wire-ran one to the ignition switch (to replace the pink resistor wire) and one out to the coil. Cranked right up-never had any problems at all! Pics if needed!

[DMikeM]

Where is the Ballast Resistor? I got a Pertronix II and my truck does not run right. I have a 1970 F250 Camper Special 390CC motor. I have looked all over but can not locate the resistor also if i had a resistance wire what would it look like?

EDIT:
Ok found out it's the pink wire under dash.

[lrjetmech]

Ballast resistor on my '69 was located on the firewall, sorta in the middle but more towards the driver's side, towards the top. It is whiteish-maybe tan colored, made out of ceramic; will have two wires going to it. Will try to post a pic when I get home if somewone hasn't by then!!!!!!

[kid]

The ballast resistor is a pink wire in the wiring harness. It comes from inside and makes its location known at the connector that has the oil and water temp wire along with the ignition wire. That connector is behind the throttle trapeze area.

That ballast resistor you are talking about is not stock on any ford since before 1955.

[lrjetmech]

Don't know about what is stock or not-I just removed the pink resistor wire from the ignition switch out to the connector which splits off to the coil/oil/temp. I removed the ceramic resistor because the directions for the Pertronix II say: " 16. Many vehicles came equipped with ballast resistors or resistance wires. To achieve optimum performance from the Ignitor II ignition system, we recommend removal of these components."
Guess the ceramic resistor could have been for noise isolation for the radio, but regardless, I removed it, and never had any problems. It was tied in with the coil wiring.

[kid]

No a ballast resistor does not cancel noise it only limits current. The reason it is called a ballast resistor instead of just a resistor is because it varies it's resistance in relation to temperature. Some are positive and some are negative. Car ones are positive the resistance goes down on the heat rising. A car at full throttle could use more voltage than at an idle.

[mljjones67]

Hey Charles do you have any pics of how you wired up your ignitor?? I could use all the help i can get!

Mike

[kaptnkaos]

Hey DmikeM...

I didn't know they put engines that small in bump trucks...

I have a 1970 F250 Camper Special 390CC motor.

Just had to razz ya a little...

KaptnKAOS

[Dunnburger]

How many ohms is the ballast resistor? What I'm getting at is I have the petronix ignitor and a stock coil, do i need to cut the ballast resistor wire? I'm confused

[mljjones67]

HEY GUYS What gauge of wire should I use to replace the resistor wire?
Mike