[TR] pertronix PEI and coil type

Tomislav Marincic tomislav.marincic at earthlink.net
Mon Nov 23 07:32:02 MST 2009


> I hope this is a simple question with a simple answer.  Does it matter 
> whether the coil has a ballast when converting to an electronic 
> ignition?
> Thanks,
> Gary O

The simple answer is yes.

The more complicated answer is that the total resistance of the coil plus
any ballast must be sufficient to limit the current through the Pertronix.

In a 6-cylinder engine, the current through the Pertronix should not exceed
4 amps. If, for example, you run a Lucas Sport Coil with 3.0 ohms of
resistance, and your coil is getting 13- or 14 volts from the alternator,
you will probably become one of the Pertronix-haters you see on the
Internet, who claim the unit "just died". 14 volts through 3 ohms gives you
4.67 Amps, which exceeds Pertronix's published spec for a 6-cylinder car.

You need to measure the resistance of the coil, and measure the voltage of
the wire feeding the coil. Volts divided by Ohms will give you the current
in Amps. If the answer is more than 4.0, and your engine has 6 cylinders,
you need to add a resistor.

Cheers, Tom


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