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Electronic Buzz Coil

DustyBar

Subscriber
Last Subscription Date
01/14/2020
I found this circuit in a 20 year old, out of print, Strictly Internal Combustion magazine. I have not built it yet but if I understand what I'm reading sparks start 2 msec after the points or wiper makes contact and then continues for 5 msec. Slight timing adjustment will need to be made for the 2 msec delay. The 5 msec duration should save the battery if the engine stops with the points or hall sensor closed. With points A and B terminals are used. With hall sensor A, B and C terminals are used. I believe it works with most any standard ignition coil. There were corrections made to this circuit in two following issues and I've shown the circuit with the latest changes.
 

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David Cave

Subscriber
Last Subscription Date
07/19/2019
This post got me thinking again. Last year I designed (lots of trial and error) and built a buzz coil based on a modern car coil - the type of coil where one sits on each cylinder of the car engine and are computer driven. The beauty of these coils is that they have internally your transistor Q2,3,4 and part of the 555 timer. As I remember my version used a coil, 2 resistors and 2 capacitors. If I can find the schematic I'll post it.
 

DustyBar

Subscriber
Last Subscription Date
01/14/2020
...buzz coil based on a modern car coil - the type of coil where one sits on each cylinder of the car engine and are computer driven. The beauty of these coils is that they have internally your transistor Q2,3,4 and part of the 555 timer...
Please do post the circuit. What engine had the coil on plug you used?
 

David Cave

Subscriber
Last Subscription Date
07/19/2019
I didn't build it for a specific engine although I did run it on a 3 HP John Deere battery/sparkplug engine. I was talking to Mr. John Deere, Jim White, one day and he threw out a challenge - could a buzz coil be built from a modern GM coil with the built in electronics. Got one working, put it in a buzz coil sized box and sent it to Jim. Now the embarrassing part, I can't find the schematic. Next time I talk to Jim, I'll ask if I sent him one. Basically I used a low valued resistor, 10 ohm maybe, in series with the module. The coil trigger lead had a RC network to delay the coil trigger. When the engine points close my module got 12V immediately thru 10 ohms, then the trigger voltage came up (thru the RC delay) and fired the coil. When the coil fired the 12V collapses due to the 10 ohms. When 12V falls it resets the trigger which shuts off the coil, the 12V rises and it repeats.
 

miro

Registered
Even simpler is the version that uses an automotive relay that provides high frequency spark occurance similar to today's coil-over-plug COP systems. Because it uses electromechanical components, it's more immune to high voltage spikes that go back through the circuit.
The coils from the COP work just fine and are much more compact that the conventional tower type coil.
 

DustyBar

Subscriber
Last Subscription Date
01/14/2020
I use the relay style on my engine now and it works well enough. The problem with it is, if it stalls and the points are closed, it will completely discharge the battery if not caught in time. The circuit in my first post, as I understand it, will only generate multiple sparks for 5 msec and then wait for the next trigger.
 

David Cave

Subscriber
Last Subscription Date
07/19/2019
I use the relay style on my engine now and it works well enough. The problem with it is, if it stalls and the points are closed, it will completely discharge the battery if not caught in time. The circuit in my first post, as I understand it, will only generate multiple sparks for 5 msec and then wait for the next trigger.
 

David Cave

Subscriber
Last Subscription Date
07/19/2019
The February/March issue of Gas Engine Magazine has an extremely simple (car coil and 3 resistors) buzz coil that functions like the Model T buzz coil. Called Evac, it starts quicker, throws a spark twice the length and has a rep rate of 10X when compared to a Model T coil.
 

Joe Romas

Subscriber
Age
76
Last Subscription Date
10/03/2019
The February/March issue of Gas Engine Magazine has an extremely simple (car coil and 3 resistors) buzz coil that functions like the Model T buzz coil. Called Evac, it starts quicker, throws a spark twice the length and has a rep rate of 10X when compared to a Model T coil.
David, I built a buzz box coil using the 5 lead BOSCH relay for ORM's speeder and it works fine but I'm wondering how long the relay will hold up under such service. Could you possibly sketch up what your describing using a GM coil pack?
Thanks
Joe
 

David Cave

Subscriber
Last Subscription Date
07/19/2019
I've used a couple of different coils - part # - H6T55171ZC and 12573190.
Also you don't need the capacitor.
 

Joe Romas

Subscriber
Age
76
Last Subscription Date
10/03/2019
Thanks David. The circuit diagram is all I need.

DustyBear. If your asking what vehicle originally used the LS2 or coil pack David uses/used I've found it listed for GM vehicles from 1999 to 2007 including at least the 12573190. Basically salvage yard material.

Joe
 
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Ronald E. McClellan

Subscriber
Last Subscription Date
01/05/2020
David , Me being old school I see your diagram as being incomplete. Where are the points/timing ? The engine ground/for points and spark plug ? Ron
 

David Cave

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Last Subscription Date
07/19/2019
As I said the whole article is in this issue of Gas Engine Magazine , GEM. The schematic in the last post was just for Evac 1, the buzz coil, not how to hook it up. Attached here is the simpler schematic, no capacitor, Evac1 and one method of connecting it to an engine. I would recommend the simpler, no capacitor version of Evac1, 99.99% of the applications don't need the capacitor. As for connecting the buzz coil to the engine, in my diagram the ignition switch is the timing/points switch on your engine while the kill switch is an added external switch to shut the engine off.
 

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Ed Stoller

Subscriber
Age
79
Last Subscription Date
07/11/2019
I am intrigued by the discussion of the GM LS2 Coil and would like to do some testing with it. The LS2 is totally new to me so I need some help with that part. But, I have been making and testing ignitions for a couple of decades and have several engine simulators which are driven by tread mill motors where I can dial in the desired RPM and gather data. My first cut at a test circuit is below. The plan is to use two trigger pins on the flywheel like on the Tecumseh HH 120, see www.enginesandmagnets.com, to operate with the GM PC2 crank sensor thru a TBD air gap to trigger. The effect of the polarity the trigger coil might have ignition timing needs to be investigated as is any signal conditioning of the trigger coil required to work with the LS2. The overall idea is to make an ignition with three ignition timing ranges: 0 to about 100 RPM no spark ( no kick back), starting at about 100 RPM with a TDC spark for easy starting, and an advanced RPM starting at about 500 RPM for best performance.

I did some pricing on conventional ignition coils and they cost typically $60, so a concept like this might be very cost effective as well as better than OEM ignitions.

Comments please.
GM-LS2-Test.jpg
 
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