Hot Rods Resistor Required

So with points we run a resistor to reduce voltage. If I've converted to a Pertronix points replacement do I still need to run a resistor?

 

No just use the Pertronix coil that has the correct resistance.

 

I always put a resistor in them no matter what. doesn't hurt and most likely will help.

 

Again Pertronix will tell you not to run one when using their Coil. I have been running both my 32's that way for quite some time. Using the Pertronix Coil insures dependability Many people have problems with Pertronix when they do not have the correct resistance. JMO

 

No, just use the proper coil for the unit you have.......Pertronix likes 12v (they will even tell you to bypass the resistance wire for a GM).

 

I have put in 3 of them, always used their coil with no problems. No resistor used on any of them.

 

what is the part number of the Petronix? Ignitor 1 or Ignitor 2? that can make a difference

 

Agreed follow Pertronix instructions with the correct coil and everything will work as designed.
I have ran a few of these over the years with no issues, they work perfect.

 

The resistor does reduce voltage, tho keep in mind the goal is to reduce current. That's what roasts points. And Pertronix Ignitor modules. 8 amps is the limit for Ignitor 1 series.

Your Pertronix most likely came with an instruction sheet. There, it will have the recommendation on what to do. Start there.
It depends on which module you have.
Where people get turned around is using low resistance coils and the wrong Ignitor.

 

You can run your stock Coil and resistor as long as the unit you buy is the correct one to do that. They have several different ways you can do things just make sure your getting the correct information when making your connections. My 51 Vicky is 14 years on there system and not a single issue.
The Wizzard

 

OK so here's a related question... I'm running a 6 volt system with points in my 1936 Chris Craft. Would that have a resistor in the system?

 

I have never used the Pertronix system, but it is a matter of how much power you are using that would determine if you need the resister to drop the voltage. I have used both CD systems for over 30 years, and an MSD system for over 20, and have never used a resister.
The instructions state to remove the resister.
http://www.pertronix.com/docs/instruction-sheets/1181.pdf
Bob

 

No, actually they don't. Not necessarily.

Again, it depends on the resistance of the primary coil circuit. It's so fucking simple people have to make it complicated.

 

Probably not.

 

Not trying to start a pissing match but, reducing voltage will also reduce current or amperage.


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Perhaps, but then, please explain why 6 volt systems operate on higher amperage than 12 12 volt systems.

Ray

 

Right - That's the whole point - to reduce current. The points don't care about voltage. Sorry if I was unclear.

 

Because they have less resistance. Ohms law is pretty clear that to raise amperage voltage needs to go up or resistance down. It takes one volt to push one amp through one ohm. Voltage and resistance affect amperage


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It depends on the ignition system, mainly coil. For example, pre-'49 Fords used a resister, while '49-'55 did not, and all 6 volt.

 

Here's where I understand it started. Ignition system designers decided it would be good to have more power during cranking than was needed just for running. So they designed for more power when cranking and used a resistor in the line when running. So turning the key to start bypasses the resistor. This is why you need components that are designed to work with one another. Pertronix has apparently decided that only one level of power is needed. Believe them. Adding a resistor to an ignition system that was designed to not use a resistor will reduce power all the time. If you are using a system that calls for a resistor you need to be sure you've wired the ignition switch so that turning the key to start bypasses the resistor.

 

Do as Pertronix says!!!!

 

Sounds good, but that doesn't jibe with the timeline. When Detroit converted to 12 volts, that's when the ballast resistors started showing up right?

Ford for example kept 6 volt gauges up until the 1980s or 1990s as well. Basically they kept the ignition system the same, and the dash, when they converted to 12 volts, and just dropped it with a ballast. That's a question - there would have been no reason for a ballast on 6 volt vehicles?

No, they determined that excessive current flowing through the primary will roast the module, in a way similar to what happens with points. Their products can be used with points - their coils for example - and their Ignitors might be used with stock coils for another example - and, they make different coils with different ohms resistance and different Ignitor modules that are designed to be used with specific coils.

Consequently there are very different instructions depending on what parts the user has installed.

Sometimes the user is instructed to leave the ballast installed, typically when the stock or OEM coil is retained. The Ignitor I is fine with a constant full battery voltage, but many ignition coils are not. Pertronix specifies that in the case of the Ignitor I module that a coil with at least 1.5 ohms resistance is used if no additional ballast is provided.