How do Atom Computer Ignition modules work?

[legendre]

quote WeedlessDrive:

Will these modules work on 1930’s opposed twin cylinder models with single coil?

If it works on a standard single-cylinder 2 cycle engine, it should work on an opposed twin.. as the opposed twin is really just a split-single, isn’t it?

I mean to say, both cylinders approach TDC simultaneously and fire as one, off a double-wire coil, correct?

[garry-in-michigan]

The mid ’30s Evinrude/Elto coils I am familiar with have a primary voltage around 5 to 8 volts with a secondary around 40,000 volts. The secondary is a single winding with each end firing a sparkplug. Grounding one plug wire doubles the voltage to the other. One wire being disconnected also kills the ignition to the other sparkplug. Both wires must be grounded when cranking an engine with the sparkplugs removed.

Edit – The spark between the ends of the two high voltage wires should jump a 13mm gap

[weedlessdrive]

So Garry do you think the single wire module that is grounded would work on a 30’s motor? The module is made to replace points and condenser on a magneto ignition. I’m going to try it. I ordered a module just to see.

[legendre]

Not Gary..

quote WeedlessDrive:

So Garry do you think the single wire module that is grounded would work on a 30’s motor? The module is made to replace points and condenser on a magneto ignition. I’m going to try it. I ordered a module just to see.

The firing geometry seems to be correct, so it’s probably down to the voltage and current requirements. Will be good to know for sure!

[Mumbles]

quote WeedlessDrive:

. I ordered a module just to see.

What brand of module? Nova II?

[weedlessdrive]

There are Kawasaki and John Deere modules (M70114) that are single wire for 2 and 4 stroke engines. They have the same exact wiring diagram used by the Atom modules for installation. The ones I found were for a whizzer motorcycle but looked exactly the same as the Kawasaki and John Deere modules.

[debe]

The single wire modules may not work unless you wire them in reverse polarity. That’s why 2 wire ones are marketed. I have used a single wire module before & had to fit a small heatsink to it & insulate the module from the motor, to reverse the polarity. With all these modules the polarity is trial & error, as it depends on the polarity of the Ign coils pulse in the primary windings. For example in Seagull outboards the Villiers coil is wired one way, but the Wipac is the opposite way. In my experiments I fount the Wipac coil on the Seagull was the hardest on the module, until I fitted the transient protection diode.

[ken-w]

I have gathered all parts but the transient diode, and put in a test board. I am planning to install into a 3 hp Seaking for testing.
http://s451.photobucket.com/user/Zypheracer/media/IMG_1771_zpslnkcfxhu.png.html?sort=3&o=0

[garry-in-michigan]

WeedlessDrive – You do nice work –

editIt worked on the 1940 Zephyr – same set up on the ’34 Lightfour Imperial and previous Quads.

[weedlessdrive]

Garry this is Ken W’s module. I would like to see how it’s done though. He obviously has some great skills.

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