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Posted by: Ansbacher Jan 24 2020, 11:49 AM

I am preparing to install a Pertronix Ignitor (1847A) in my '74 2.0L with dual carbs. I am running a stock coil. The instructions mention the possibility of the presence of a ballast resistor in the ignition system. How do I determine if my car has one; where would it be located? Or, do I perform an ohm test of some sort to tell? If so, what is the procedure?
Any help much appreciated.

Ansbacher

Posted by: malcolm2 Jan 24 2020, 11:56 AM

It would be between the coil and the electronic module. I had to add one to mine to keep the volts down and not burn up the module. I don't have petronix, I used HOT SPARK.

So if you are going from points to electronic, I would say you don't have one. Mine are just a white ceramic looking block 2" long with male connectors on each end. I had to go thru four or five "sizes" to get the volts down.

Posted by: Tdskip Jan 24 2020, 11:57 AM

Get other opinions here but I think not, don't want one in the circuit.

Posted by: porschetub Jan 24 2020, 12:17 PM

QUOTE(Tdskip @ Jan 25 2020, 06:57 AM)

Posted by: malcolm2 Jan 24 2020, 05:20 PM

This is what the HOT SPARK folks say the BR is for and how to install etc....

External Ballast Resistor: If the charging system voltage, measured at the coil's + terminal, is more than 14.0 volts at any RPM level, the voltage regulator likely needs replacing or a 1.4 Ohm ballast resistor should be wired between the coil's + terminal and the red HotSpark ignition wire. Too much voltage can damage the ignition module and other electronic components.

Again, this is HOT SPARK. You should check and see if Petronix has similar tests.
Was your question, should I install a BR, or Do you currently have a BR? I thought it was the latter.

Posted by: DickSteinkamp Jan 24 2020, 06:04 PM

QUOTE(malcolm2 @ Jan 24 2020, 03:20 PM)