Ballast resistor and electronic ignition ?

Hello.

In my F-134 engine:
If i swap to electric ignition (distr.) will i need the old ballest resistor ?
As i understand its purpose is to "save" the point life, and i wont have any points in the new distr. Right?

Ziv

 

Re: Ballest resistor and electronic ignition ?

Which electronic distributor are you going to use? Most, if not all, need a full 12 volts thus not needing the resistor.

 

I believe Timgr is running a Motorcraft electronic ign that requires a resistor..

 

Actually I'm running a 3 ohm Pertronix coil with an external GM HEI module and Motorcraft distributor on the CJ-6. The J20 has a factory-equipment 100% Motorcraft setup, and it has a resistance wire somewhere.

Whether you need the ballast resistor or not depends on how much current the electronic control module can sink without overheating. It does not hurt anything to add more resistance in series with coil, except that you'll reduce the spark voltage some.

 

I’m running a Mallory ignition system (magnetic trigger distributor, CDI box and coil) and without the CDI box it would still need a ballast resistor.

 

Yes and no. You are correct in that you aren't supposed to exceed the current rating and voltage drop of the coil. If the coil calls for a ballast resistor, then the internal resistance is too low to keep the current within a safe range in that application. Some modules are current limiting (apparently), some are not. If you connect a low resistance coil (ie TFI) to a module that is not current limiting (ie Duraspark), you'll blow up the module (typically) before you cook the coil (as I understand it).

So yeah, the module matters.

Sorry if this sounds like weasel words, but I understand the electrical issues and don't know the specifics of every module.