But I need to correct you. It takes some milli(mycro)seconds till a spark jumps
between the electrodes, even there is extremely high voltage between the
electrodes. A good electronic ignition system is able to build up these high
voltages before the spark jumps over at the electrodes of the spark plug. So
there is a much better chance with an electronic ignition system to have other
(smaller) spurious spark jumps along the high voltage path of the ignition
These effects may cause the troubles with the rotors.
54BN1, 62BT7, 65Sprite
PS: No problems so far with rotors on my Healeys (with old fashioned points and
Von: firstname.lastname@example.org [mailto:email@example.com] Im
Auftrag von Frenken, Eric
Gesendet: Freitag, 10. November 2006 09:47
An: David Nock; Healey List List
Betreff: Re: Ignition rotors survey
I don't believe that simply using electronic ignition causes higher voltage.
The electronic ignition would be able to deliver higher voltage if needed, but
doesn't do this in any event.
With every ignition you have in your engine there's so much voltage generated
as just needed that the spark jumps between the electrodes of the spark plug
(or anywhere on the way to the spark plug should resistance be lower at that
point). Electronic ignition (and high voltage coils) can generate a lot more
voltage in special situations (e. g. high compression engine), so that the
spark can jump between the electrodes even when the resistance is getting
Imagine a garden hose whose opening is closed partially. Water will come out
with a higher pressure than when the opening is not restricted. You can compare
the blockage of the opening with electrical resistance and the pressure of the
water with the voltage.
My guess about rotor failures is, either you've been lucky obtaining good
rotors in the past or, more likely, you as British car specialists install the
whole ignition system as it should be installed.
Please find attached my replies in your survey.
David Nock wrote:
I am trying to get some info on all these rotors that you all are having
problems for a future article.
1. Which rotor are you using that failed??___none________
2. What are you using for a coil? __Pertronix High Voltage 40kV__
3. What distributor cap brand? ___Bosch____
4. What plug wires
Carbon____X_______ Steel core____________
5. What style ignition
I have a feeling that a lot of these rotor failures are caused by the higher
voltage when using an electronic ignition. Since we rarley install electronic
ignition and we rarely have a rotor failure here in the shop.
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