Terry,
Was your electronic ignition a Pertronix unit? How old? Apparently the
newer Pertronix units are more sturdy than "older" ones. I don't know what
they changed, or when. Any idea why it failed?
I have heard of enough failures to have me concerned. I have a Pertronix
and I always have a slight worry about being left dead on the roadside.
I suspect 2 sources of failure for these Pertronix ignitions. 1) heat, and
2) voltage spikes.
1) If you turn on the ignition without the engine running, then MAYBE the
electronic ignition will supply current to the coil continuously. There is
significantly more current running the switching device in the Pertronix
(presumably a MOSFET) than if the engine were running. Some ignitions will
shut down the output if the engine is not running. That heat may slowly
degrade the device until it can not hold up under normal running conditions.
It is asking a lot to pack a device switching fairly heavy current into such
a small package, and in a closed environment. Heat may well be an issue
2) I had what I later determined were some horrible spikes getting into my
electrical system from a failing ignition wire. The old original cap, with a
spike holding the wire in place just sucks. I replaced it with an MGB (oh
the horror!), and Magnecore-type wires and it has been fine for 3 years.
The reason the spikes were happening was that periodically there was a lot
of resistance in the wire and all that juice had to go somewhere. It took
out an old original voltage stabilizer by shorting the heater windings. It
then destroyed a replacement transistor-based stabilizer. That unit used a
60v transistor. I have since repaired it with a transistor with a voltage
rating as high as I could get and still have it fit.
Something took out your electronic ignition, and you probably should try to
prevent it from happening again. External ignitions, like the Newtronic
Systems, etc. are almost certainly more durable.
-Tony
----- Original Message -----
> Date: Sat, 25 Sep 2010 15:03:19 +0000 (UTC)
> From: terryrs@comcast.net
> Subject: [TR] Looking to buy:
> To: triumphs@autox.team.net
> Message-ID:
>
><1953773937.1376061.1285426999049.JavaMail.root@sz0059a.westchester.pa.mail.comcast.net>
>
> Content-Type: text/plain; charset=utf-8
>
> Yesterday stranded in a parking lot, had to swap out electronic ignition
> back to points. It would have been so much easier if I'd already had them
> mounted on a contact breaker base.
>
> So, anyone want to sell a spare breaker base set that'll fit a Lucas 25D
> distributor # 40795A? These are, alas, unobtanium. If not, I'll check
> with some of the usual suppliers of used things of this ilk.
>
> Terry Smith
> '59 TR3A TS 58667
> New Hampshire
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