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Exciter for coil over plug

Thread starter #1
I am looking for a circuit to fire a COP coil with 6 volts DC . Similar to old Ford T buzz coils. It will be used on an old antique engine ignition.


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Welcome to ETO!
What will you use to trigger the circuit?
Thread starter #3
A mechanical ground (To battery negative) trip similar to Fords system. I want to isolate coil and PCB from engine frame. As this will be in an area of vibration, heat,and oil/water splash. FYI most all antique engines used water cooling, drip oilers, and operated at 212 degs.
Thanks Rudy


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I want to isolate coil and PCB from engine frame.
Well, you can geographically/mechanically isolate it, but battery negative (hence the trigger/pcb) will be electrically connected to the engine frame.
Thread starter #5
I can do all these, I am aware that I will need to use COP GND as return for COP trigger as well . I need a circuit to try, it should be as simple as possible since it will be used in the field.


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Googling 'transistor ignition' brings up several circuits you could try.
Thread starter #8
I have seen a circuit done on 12 VDC did work for a while, the operator did not address heat and high voltage spikes (My opinion) . I can address the 12 volt challenge. As to dwell time that can be adjusted by point timing. Buzz coils we do not worry, how ever as you stated COP may over heat? Gotta try !!!!
I still need someone who has a circuit that will fire a COP ..


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While not for COP coils these could probably be adapted, since they are made to be used on hit and miss engines. There is quite a few guys in this area that collect H?M and other antique engines, but can't recall any of them using a Model T type buzz coil, but wasn't really looking for one that did. Most of them have 'low tension coils' on them. Won't the engine look funny having a COP coil on it?

Around here they get around the 6V problem by hiding a 12V motorcycle battery inside a empty 6V battery. The 6V shell just lifts off to charge the 12V as needed. What make of engine are you making this for, if I may be so bold to ask?

The site has a lot of good information. http://jerry-howell.com/IgnitionModules.html
Thread starter #10
A 1923/1927 Witte (pronounced Whitty) I have seen many points fired engines I have a 1/8 scale late 1800's Olds handy man engine hit and miss it will run all day if it is feeling good!!!!!!!!
How ever older and bigger engine sometimes run better with a buzz coil. I would like to make a FAUX magneto using modern tech and make it look like the real thing. Fouling of plugs and oil (they use drip oilers) can and will foul plugs depending on the moon phase, if your karma is just right, or for any other reason?

With a buzz coil fired engine in a pinch I'll bet it would run on shredded paper !!!!
Hope some one can find a circuit that will give a buzz coil spark on a coil, mag out of a weed whacker, or COP. As I said I saw one but owner would not share!!!!
Remember the CD ignitions? They used a high freq spark at higher voltage and would work great. I still have one but I want a FAUX mag to do the same.



Well-Known Member
There are lot's of places to look for this, on google,https://www.google.com/search?q=modern+ignition+for+hit+and+mis+engines&ie=utf-8&oe=utf-8 The guy's at Smokstack.com have put out a lot on this. I haven't been keeping up on these engines for quite a while, I'm a machinist and made many parts for a friend that was into these engines. But since he passed I haven't even been to a engine meet for quite a while.

A search for "electronic buzz coil" give many hits and ways too. https://www.google.com/search?q=electronic+buzz+coil&ie=utf-8&oe=utf-8

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