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SP250 twin coils

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Beat Weibel
Posts: 185
Joined: Sat Feb 27, 2016 4:13 pm
Location: Munich

SP250 twin coils

Post by Beat Weibel »

Hi SP250 experts

Just a thought that struck my mind when I was reading literature about ignition. Maybe it has already been answered or tested or is maybe even a common tuning measure :
Since the SP250 distributor has to separate points - why not using two separate ignition coils separately controlled by the two points, respectively? This would eventually give a stronger spark and more power.

Any experience with this idea or complete nonsense?

Could be realized with electronic ignition as well.

Looking forward to your comments, best regards
Beat

Sydsmith
Extremely Wise Man
Extremely Wise Man
Posts: 1369
Joined: Sun Feb 14, 2016 11:15 pm
Location: Aberystwyth Wales

Re: SP250 twin coils

Post by Sydsmith »

Beat, it is difficult to see the advantage.

Using individual contact sets to energise individual coils could be engineered somehow no doubt, but then we have the problem of connecting the high voltage end from two coils to the single input point.

Quick response, so I have not thought out how the output from two coils would work electronically, but even if they don't defeat each other I can't see how a reliable connection of the two outputs could be made.

Apart from that there is a delay between the opening and closing of the two sets of contacts which would mean the ignition voltage timing on each coil would be out of step.

There are very much easier ways of increasing the ignition spark if that is what you need. Two coils? Not worth the effort in my view, but no doubt you have started something here. Syd

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JohnM
Posts: 206
Joined: Thu Feb 11, 2016 1:31 pm
Location: N W London

Re: SP250 twin coils

Post by JohnM »

Hi Beat,
no, it wouldn't work, I'm afraid!
The reason for the two sets of points is to give the coil time to charge - the charge is set when one contact set opens, then the coil discharges when the other set opens. As Syd says, running a coil off each set of points would result in poorly charged coils and very confused ignition!

You can of course run quite happily on what is effectively one set of points when you move to electronic ignition, where the coil is charged differently and the "points" simply tell the unit when to discharge the coil.

Good lateral thinking, though!

John
John M in Middlesex, NW London
1962 SP250 "B" Spec
DLOC Herts Region Sec

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