Nat

Coils/Pertronix/Pertronix ll/Pertronix lll/Volts/Amps/Olms what does it all mean and why do I care?

You care because you want your car to run. Two many AMPS heat up the coil and kill it.

If you have points and a condenser OR a Pertronix (basic ignitor) then you MUST have a coil to support it. A  coil that has AT LEAST a 1.50 Olm resistance with a ballast resistor.

The ballast is wired so it is powered and then it provides power to your coil AFTER THE START POSITION of the ignition switch is released and then placed into ON. TWO SEPERATE CIRCUITS that both provide power to the coil through the ignition switch. One to start with high voltage (amps) one to run with reduced voltage/amps (via the ballast resistor)

Pete

If you look more at their website you will find documents that describe how to test your coil and to evaluate whether you need a ballast resistor. I think that in your case that you must have a resistance to avoid the coil is boiling. This has nothing to do with the coil is located on the intake manifold. It depends on how much amperage load to the coil with understatement. Occasionally, some models of the structures do without a resistance when the cable from the ignition switch is working and helps as a resistance. Then it's usually an extra cable mounted on the starter motor to provide 12 volts when it starts. Petronix Flame Tower can not handle 12 volts continuously. A car should have a resistor fitted, and it turns out that it works still have problems with voltage drop. This can often prove to be a sluggish engine started.

Drives: Mercury Montclair 1957th

www.mercury1957.com

I just had thsi hot coil issue happen with my t-bird today as well.  I have the Mallory Unilite module in it, with therecomended ballast resistor.  It had started running bad when ever it gets hot and started dying at the worst times in traffic.  Today I had a votmeter with me and I found with the votage at the coil at that time was around four volts, then with another coil , made for Duraspark, the coil had 9 volts to it just like mallory recomends.  Apparently, the coil had developed a bunch of internal resistance when hot.   I have been sucessful with this combo for the last nine years, so it was hard to diagnose.

I also had a bad rebuilt alternator this spring.  It was allowing the battery to discharge while driving, then it would not crank very easy when it died or I had to restart it.   I though the low voltage wa causing the ignition to loose voltage when the battery got low at that time. 

We are taking the bird to the Lone-Star Round-up in Austin on April 13th, so I have to get this sorted out.

I had a hot stall issue with a brand-x customer car with Pertronix1.   We had to add a resistor to the coil. That car has worked perfect since.

Pat Fleischman

I contacted the technical department at Pertronix about this very issue, this is what they said: An oil filled ignition coil should always be mounted in the vertical position, this applies to all brands. When the coil is vertical the windings are covered by the oil. In this position the coil will have the longest life. An oil filled coil can be use in a horizontal position but expect a reduction in it’s life. If you must lay the coil in a horizontal position make sure the post are in a horizontal position. The shortest coil life would be in a horizontal position with the post in a vertical position.



Gibraltar, MI

55 T-Bird

I fought this same problem for ages with my '56. I had a Mallory electronic system with a Mallory no-resistor coil. All was brand new. From the get go if it got to 190 it would quit. I thought it was vapor locking & I chased that for 2 or 3 years. Finally one day it died & the coil was hot as hell. I put a MSD coil on it & when I got home I mounted it vertically & put the suggested resistor on it and that was the end of my problems (knock on wood).

Doing Fords for 45 years. '56 Customline Victoria

E.J. in Havana FL

With the Pertronix Ignitor I units, I’ve always used the ballast resistor to the coil.  It’s the Pertronix Ignitor II and III units that I install without using the ballast resistors.  Raising or elevating the coil so it’s simply higher and resting on Bakelite or a similar heat dissipating material may help to keep some of the intake manifold heat from transferring to the coil.  There are several Thunderbirds currently being driven around that moved their coils to the firewall which alleviated coil issues in those instances.  Probably didn’t fix the root cause but at least this gets around the original problem of the coil overheating to the point of failure.

Lorena, Texas (South of Waco)

Hey guys thanks for all comments.

I just heard back from a Pertonix customer rep. He suggested hooking up the Flamethrower to my external resistor. My original instructions from Pertronix was to bypass the external resistor. The Flamethrower has an internal resistor. Will hooking it up to an external resistor cause any performance issues or damage?

My problem was that the coil would fail when it got hot. Severe misfire under acceleration.





Thanks

The "chips" in the later Pertronix products - "II" and "III" - have more sophisticated current regulation schemes than the original. Because of this feature, they are better able to control the heating tendency of the coil at low RPM. Without digging any deeper, I'd say its the same or similar to the GM HEI setup - may even use the same Motorola chip design or a copy. Probably increased the current rating of the grounding transistor at the same time.

   

 
 Steve Metzger       Tucson, Arizona

Nat;

I run the Pertronix II ignition with an MSD Blaster coil and no ballast resister and have had no problems for the past 3 years.

Rono

  Ron Lane,  Meridian, ID

Basically all of the original Ignitor units have to limit the coil primary OHMs to 1.50 or more. If you use a coil with more OHMs it doesn't care - and if it is an original coil or an original plus a ballast resistor, its just more protection for the grounding transistor - less AMPs to switch. Protecting the transistor is a necessity for long life of an Ignitor I system. Finding a coil that takes the heat of direct attachment without a ballast resistor is another.

He might be able to use a cylindrical coil intended for use with the Ford Duraspark II system - they are less OHMs than the standard points coils but more than the Pertronix 1.5 OHM minimum by a safe margin. They are also designed to be used with fixed dwell / transistor ground systems. In the stock Ford arrangement they are fed through a 1.35 OHM resistance wire - but if I could find one as a salvage part (with the mating wiring clip), I might try it out with full voltage.

MSD has a ballast resistor that is .88 OHMs and it might be used to to "tune" a 1.5 OHM primary coil to a slightly lower AMP load - less heating. So long as it is wired as the diagram Charley attached - it won't cause problems with the Ignitor itself. As Nat remarked early on - the performance will be lower the higher you go over the 1.5 OHM minimum - but if reliability is suffering, its not worth the hassle.

 
 Steve Metzger       Tucson, Arizona