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Old 12-04-2008, 12:15 AM
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xPosTech xPosTech is offline
The Old Master Motorized Bicycle Builder
Join Date: Oct 2008
Location: SETexas
Posts: 209
Default Re: has anyone seen this?

I guess I'm not the only one dreaming.

Check out fan patterns for lacing the wheels.

The only dwell extenders I'm familiar with was way back in the sixties. I built one for my Goat in '68. It just electrically closed the points a few milliseconds after they opened. It extended the dwell time that the coil had to build flux. The coil only built flux when the points were closed.

The maximum flux is the saturation point of the magnetic coil. Sorta like charging up a capacitor. The more time the coil has to build the charge, the hotter the spark.

This was an 8 cyl. engine with one coil. I'm not sure a 3 cyl. would benefit that much if it used points and coil. A single wouldn't benefit (unless it ran some ungodly RPM).

The radials used magnetos. They also didn't idle. No throttle. Wide open or off.

I'm not aware of any dwell extenders that directly/intentionally vary timing. The reason that "old" ignitions had a dwell adjustment was a dynamic setting of point gap. The wider the gap, the shorter the dwell time. Instead of specifying point gap, high performance engine manufacturers specified dwell. The lower the dwell percentage the cooler the spark.

The dwell also affected timing to a slight degree (heh), but it was largely a mechanical/electrical delay for the points opening causing the coil flux to collapse and the spark plug to fire. The relationship of the plug gap and point gap also affected it.

The wider of the two determined actual fire time. It also minutely delayed timing. If you have a stout enough coil, you can narrow the gap(s) and advance timing slightly.

This was about or a little after the time MSD developed their ignition. The CDI (and electronic flash for cameras) about the same time or a little before. And dwell extenders became . . . moot.

This is all from memory. I was just gonna mention dreams. Y'all can gargle and see how wrong I am (again).

I need more caffeine.

I wasn't born in Texas but I got
back here as soon as I could.

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