that's the K-mart coil trick. The cheap (less than 10 bucks) coils that
you find in any store with a auto parts aisle is actually a pretty good
coil. You can run them without ballast for a long time before they fail.
In CD systems there is no reason for a ballast resistor--doesn't do any
good. the rise time of the voltage is so fast and the back end of the
pulse is so steep that the coil hardly gets heated. Ballast is there to
manage the amount of heat generated during the point dwell (the time that
they are closed). CD's don't charge the coil to saturation and then open
the coil to collapse the magnetic field and get a spark--they have a
rapidly rising pulse and a much higher primary voltage. no ballast
required.
I don't know anything about the newer ignition systems--they might be
different. I designed and built my own CD systems back in the days of
descrete components.
-----Original Message-----
From: WEmery7451@aol.com
To: Bill Babcock; jerryvv@alltel.net; fot@autox.team.net
Sent: 6/18/2003 9:50 AM
Subject: Re: Pertronix Ignition points sustitute system
In a message dated 6/15/03 10:50:11 AM Pacific Daylight Time,
BillB@bnj.com
writes:
<< Your old coil may not like your new system. Coils with a lot of
broken
down insulation don't like hot ignition systems.
>>
Back in the early 70s, I installed a capacitive discharge system, and am
still using it today. I was told to install a standard parts store
coil, with no
internal resistor. I also installed two, three position switches (up,
down,
and off in the middle). I can redirect the primary current through an
external
resistor so that the distributor points see the full current and
function in
the ancient manor of the 50s. This is a backup should the capacitive
discharge unit fail.
The CD unit failed once when it was brand new, due to some over
exuberant
tech. inspector requiring me to use a kill switch that also cuts out the
generator. For the last two decades, I have been just breaking the
battery ground,
and not telling anyone about not cutting out the generator.
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