A general rule of thumb is electronic ignitions usually do not require a
ballast resistor and use a low resistance coil (~1.2 Ohms, Petronix,
Crane), points usually use the ballast resistor w/low resistance coil or
they use a high resistance coil (~3 Ohms, Lucas Sport, Bosch Blue). The
advantage that I have heard is that the ballasted coil makes the car
easier to start. The ballast is placed between the ignition switch and
the coil, when the car is starting it allows full power to the coil, you
have 12 volts going to both ends of the ballast. If you use a low
resistance coil with no ballast in a points system the coil will
overheat and the car will die.
HTH,
Don
57' BN4
-----Original Message-----
From: owner-healeys@Autox.Team.Net [mailto:owner-healeys@Autox.Team.Net]
On Behalf Of Jorge Garcia
Sent: Friday, October 22, 2004 10:30 AM
To: Austin Healey
Subject: Ignition coil question
I replaced the ignition coil that came with my car (1965 BJ8) with a
generic coil that does not use a ballast resistor. Can someone tell me
the benefits, if any, of using a coil with a ballast resistor? Now that
I am trying to diagnose the cause of the backfiring and cutting out at
higher rpm the coil becomes one of the suspects.
Thanks
Jorge Garcia
Houston, TX
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