Re: coil running of car battery(s)?

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Chris Watkins" <tesla@xxxxxxxxxxxxxx>

> Original poster: "Jim Lux" <jimlux@xxxxxxxxxxxxx>
>

> Something to think about.... The ignition system already includes a high
> current transistor designed to put pulses through the coil.  Use the 555
to
> drive the lowpowered input to the HEI ignition module, rather than just
> using the coil  I haven't researched this recently, but it seems that the
> ignition module (the part between the pickup coil and the ignition coil)
> should be readily available cheap (possibly as part of the system on the
> distributor?)
>


Wow. A topic about which I have at least "half" a clue :-)

Being an ex-wrench turner... I have played some with HEI (and other)
ignition coils. My early attempt was to wire up a hi-speed blower relay
in buzzer mode which, after tweaking of the relay contacts, did produce
nice 1/2" or so sparks. Drawback: Even with a capacitor protecting the
contacts somewhat... these relays won't last long when used this way.
(I think I managed almost 45 minutes continuous, on the best one)

The modules aren't terribly expensive. Around $18 for a Wells unit,
to $40 or so for a factory one, the last time I remember pricing them.
The cheaper units have a higher "dead on arrival" percentage, and seem
to be far more sensitive to being properly heat-sinked... but work fine.
If not using the distributor as a heat sink, make sure to use a good
heat sink compound, and a nice beefy heat sink. Force air if needed.

My very best "spark box" was rather bulky, but very effective. I simply
used a complete distributor, rigging a simple belt drive to a blower motor.
I mounted the coil remotely, extending the leads from the ignition module.
Just wire the distributor exactly as is done for the car, and use a rheostat
or multi-tap power resistor to control the motor speed. (spark frequency)
Since the pickup coil, stator, and ignition module are being used basically
in the manner for which they were designed... it'll last for a very long
time.

The older (1975-1981) GM setups are best. I've also used an '86 Ford
distributor/module/coil setup in the same way... with very good results.

As for using a 555 to drive the ignition module, I can't think of any reason
that wouldn't be just dandy. In fact, as long as the ignition module is kept
from overheating with a proper sink... it's probably the best idea I've
seen.
(Sure takes up a lot less space and power than a motor and a distributor!)


--
Chris