Ballast Resistor Question: Do I need one with a Pertronix conversion and stock Toyota coil? (1 Viewer)

[estoltman]

I have a ballast resistor with my stock Toyota coil and have Pertronix conversion (Condenser unhooked).

I haven't been able to find a definitive answer on whether I need to retain the ballast resistor with my factory coil and Pertronix conversion - I have read Yes and No.

That's the first question.

2nd question, if I convert to a Pertronix coil, assume I do not need a ballast resistor? And is their coil worth the swap?

I have to say, this FJ40/2F is trickier than my 2nd generation Supra was to work on. I didn't any resources other than the factory manual and some basic mechanic/performance common sense back in the 80's and did all sorts of mods to that engine (fine tune fuel injection, ported heads/intake/exhaust, reground cam, valve spring shims, higher compression/overbore, etc) I can't even figure out the ignition system on a 2F!

 

[B y r o n]

I think your best bet is to contact Pertronix and pose the question to them, they should know.

 

[brian]

no their coil isnt worth it.

 

[Green Bean]

On our 1970 with Petronix ignition, I ran with a Petronix Flame thrower coil for a while before eventually switching it out for a NOS Nippon Denso Coil With Internal Resistor. I cannot tell any difference in performance.

 

[estoltman]

no their coil isnt worth it.

Do you recommend the factory coil or something else?

 

[brian]

Do you recommend the factory coil or something else?

as long as the oe is working, there is no need to replace it. there really is no up grading them, despite what flashy ad men might have to say.

 

[POTATO LAUNCHER]

No need for the ballast resistor on the Pertronix kit. It runs on full battery voltage.
On a stock points set up the initial start is at 12v through the starter soliniod. Once it is running the ballast resistor drops the voltage to a lower voltage, like 9 volts, to increase points life.
The stock coil will work fine, no need to add snake oil gadgets into the low revving stock motor.

 

[estoltman]

No need for the ballast resistor on the Pertronix kit. It runs on full battery voltage.
On a stock points set up the initial start is at 12v through the starter soliniod. Once it is running the ballast resistor drops the voltage to a lower voltage, like 9 volts, to increase points life.
The stock coil will work fine, no need to add snake oil gadgets into the low revving stock motor.

Thank you! Love that name - Potato Launcher - I built one in 2001. Uses Right Guard spray deodorant (safer and as effective as ether). Lots of fun!

 

[Steamer]

If you’re going to eliminate the ballast resistor, you should change the coil for one designed to run without a resistor. The one that gets matched with a resistor is designed/wound to run on reduced voltage which occurs during cranking. When cranking, the resistor is temporarily bypassed and after cranking the resistor is re-connected for continuous running. If you run that coil continuously without a resistor, you won’t hurt the Pertronix, but the coil will most likely run hot and have a shortened life expectancy. You can check which coil you have with an ohm meter.

 

[estoltman]

Mine reads 1.3 Ohms on the first measurement above. I guess that means I have an internal resistor and don't need an external resistor.

My measurements on the next 2 steps are 21.6 K ohms and 2.3 ohms

 

[pjohnson]

I guess that means I have an internal resistor and don't need an external resistor.

No, I think that means your coil is designed for use with a resistor.
Coils don't have internal resistors.

 

[estoltman]

Thanks for the clarification - that was the other way I read it so wanted to confirm.

 

[Steamer]

Coils don't have internal resistors.

Exactly. The term “Internally Resisted” can be confusing. I used to think there was actually a resistor inside and some how it got switched off & on inside there like with a thermistor or something. Internally simply means there are more windings inside, and it equates to the resistor & coil combo. The only reason for having the resistor/coil combo is so the resistor can be bypassed during cranking and make up for the voltage drop caused by the high amp drawing starter. Not necessary for the Pertronix.

 

[estoltman]

thank you. When you say not necessary for the Pertronix, are you referring to the bypass at start or saying the resistor is not necessary for normal operation?

 

[Steamer]

thank you. When you say not necessary for the Pertronix, are you referring to the bypass at start or saying the resistor is not necessary for normal operation?

Not necessary to have the resistor/coil combo and a bypass setup for the Pertronix. The Pertronix will work fine with a voltage drop from cranking.
If you keep your coil and resistor but don't have a functioning bypass setup, you'll be fine.
If you eliminate the resistor and get the higher ohm coil (2.6 - 4.0) in the diagram above, you'll be fine.
if you eliminate the resistor and keep your coil, I believe the coil will overheat and have reduced life expectancy but probably won't hurt the Pertronix.

If you have an operational bypass setup, I would just keep it as is. The bypass is controlled by an additional contact in the starter and the starter will have a second small terminal on it with a wire going from it, to + side of the coil. Often starters get replaced with an after market starter with out the second terminal (and contact) so the bypass is just left disconnected and there is no operational bypass but the vehicle runs fine.

 

[estoltman]

Thank you. Pertronix replied back and said I could remove the resistor, but I think they are just considering their product in the distributor, not the heat build up in the coil as you point out. I asked the tech to confirmed the coil won't over heat. Unless I hear otherwise, I will leave the resistor in!

 

[Steamer]

I would try to confirm whether or not your bypass is operational. Your starter would have the one big wire going directly to the battery and two smaller wires. One from the ignition and one going to the coil + terminal.

 

[estoltman]

That's a good question. Come to think of it, I don't think it's operational. I have 3 hot wires going to the ballast resistor and then one wire from the other end of the resistor going to the + terminal. So that would tell me no bypass. The wiring diagram shows ONLY 2 wires going to the Coil - one to the resistor from the ignition (for normal operation) and one from the starter directly to the + terminal on the coil. No idea what the 3rd wire is!

 

[Steamer]

Do you have two small terminals on the starter? A pic of the starter would be good.

 

[Steamer]

If that wire from the starter is the bypass wire, then it should go to the other terminal of the resistor. (left side)
One of those other wires on the right resistor terminal should be coming from the ignition switch and would be hot when key is in the run position.
The other wire on the right resistor terminal could be going to the carbs fuel cutoff solenoid but I'm guessing. Maybe you could trace it.