All this goodness about regular coil/points ignition AND they're legal too! ;0)
(VARAC don't allow such shiny red boxes on vintage (pre 1962) cars)
I went (in my 1967 engine) to the magnetic switching electronic system put
out by JAE (http://www.jaeparts.com/). I use it with a Bosch coil that I
seem to have a bunch of, with no resistor. It's worked fine for a few races
now, and I carry a complete points setup to swap it out if it fails. My
theory on no resistor (the coil, like most quasi-modern coils, used a
resistor in the original application) is that since I don't run a charging
system, the coil sees a volt or two lower working voltage than would be the
case with an alternator running, so the current draw is lower. Also, I want
the system to continue to run even if the battery voltage drops to 10 or 11
volts (perhaps drained after a hot start following an impromptue parking
session on the verge of the track)
For those who worry about such things, I have an article by Ted Martin that
discusses electronic ignition tests that he had performed on his F Junior
engines as early as 1962/63. He says that they show promise, BTW, and
proved advantageous at higher RPM's but might be unreliable (1962, I think
damn near everything with transistors was unreliable by definition!).
One of the hardest to diagnose problems I ever had was an engine that would
run for 30 seconds and then quit. It would start right up, ande repeat this
for as long as we had patience. It was the coil...now I feel I should whap
a new coil on as I get ready to start to diagnose a new problem, just in case.
Testing on May 14 - I can't hardly wait!
Brian
At 12:14 PM 4/27/99 -0400, you wrote:
>To the List:
>
>Just thought I'd throw my 2 cents worth in here as I formerly designed
>electronic ignition systems for Motorola.
>
>A common misconception is that a CD ignition is a "high performance"
>ignition. Acutally, most CD's produce far lower spark energy than
>conventional inductive storage types. What CD's do, is produce a very quick,
>high voltage pulse that's helpful in lighting oil-fouled plugs. However, the
>spark duration is much shorter (usually 10 times) than an inductive storage
>signal.
>
>The spark energy is determined by the product of the voltage times the
>current times the duration, or the area under the spark pulse.
>
>Lean burning engines (which most should be if they're producing maximum power
>and minimum emissions) need lots of spark energy to keep the mixture ignited
>under the high turbulence and swirling conditions in the cylinder. High
>energy, inductive storage systems are better at delivering this energy than
>CDs, usually. Multiple spark systems also have advantages, as they can
>re-light the fire if it goes out, but this is done at the expense of total
>energy as multiple sparks must now fit into the same spark time as one long,
>high energy spark.
>
>After studying and benchmarking MANY ignitions, including magnetos, I
>recommend a good, high energy inductive storage ignition. To get high
>energy, you usually have to go breakerless as the ignition current at idle is
>too high for points to live reliably. Unless you have bad rings and an
>engine that regularly fouls plugs (then you really have other problems), you
>really don't need the 40KV - 80KV initial spike a CD provides. What's more
>important is burn time.....go inductive storage.
>
>OK, I'll shut up now.
>
>Myles H. Kitchen
>1965 Lotus Cortina Mk1 #128
>
Brian Evans
Director, Global Sales
UUNET, An MCI WorldCom Company
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