I enjoy making scale model gas engines and restoring cars.
Here you will find links to my Home machine shop and some of my scale model gas engines. I do all the machine and fabrication work to create these miniature working engines. I also restore full size Hit & Miss engines.
If you're interested in an ignition system designed for your scale model gas engines, take a look at my Buzz-Fire transistorized buzz coil kits ..They are designed for slow running Model Hit & Miss Engines but should also work on full size engines. If you have a bad magneto and can't get parts, you can install one of my modules inside your original mag.
It's small and easy to conceal . . Here's a little about them.
Just what is it and how does it work? This is a simple transistorized timing circuit and its use is sometimes referred to as a buzz coil. When triggered, it creates a pulsed voltage output signal, which is connected to a compatible ignition coil. The result is a multiple spark, not just a single spark at the spark plug. To save your battery and reduce the possible overheating to the Buzz-Fire components, it has a control circuit which limits the duration of the signal to approximately 20 sparks per trigger interval.
POINTS OR NO POINTS ? . . .
You can now replace your troublesome mechanical points with a miniature transistorized magnetic pickup that senses a passing magnetic field. The pick-up is referred to as a HALL SENSOR. As long as the correct (south) pole of the magnet, which is usually embedded in the cam gear, is adjacent to the face or printed side of the Hall sensor, the Buzz-Fire module is triggered. And by using an extremely powerful yet small NdFeB Neodymium rare earth magnet, the total space taken is 1/8th inch. It is almost undetectable and easy to hide. It is not affected by oil and dirt, and normal engine heat
Will this work on my ????
I keep getting questions about what this will work on . . the most honest answer I have is I don't really know about every application . . Keep in mind, this was designed to be a small package and be used on model Hit and Miss engines . . They are generally slow running and only require about 1 firing pulse every 4-6 seconds. I have used it on faster running and consistent firing engines successfully . . Electronically, I don't see a reason for it to not be adaptable to other uses by some enterprising individual . . The main problem you may encounter is overheating the power output transistor by a high firing rate. If that is your case, add an aluminum plate under the main power transistor as a heat sink. Likewise with the use of a large automotive coil. While I have used some different coils with success, I personally feel that any coil which consumes high amperage will eventually overheat and damage the Buzz-Fire components. The primary winding of your coil should not be less than 1 ohm. Coils that I have successfully used measure 1 to 2 ohms resistance. Thats the best guidance I can offer. If you choose to use the module for an application other than the intended purpose, thats entirely up to you . . with a heat sink it will probably be just fine. What do I need ??
You'll need a 6 volt battery, an ON/OFF switch, and an ignition coil. Since the Buzz-Fire creates its spark when the points are closed or the Hall Sensor is energized, you'll need to re-time your engine . . .
How do I wire this to my own coil ????
The Buzz-Fire circuit has 2 output leads . one is a constant positive 6 volt supply and the other is a pulsed ground. These go to the input leads on a coil. I know my coil and also the Exciter Model coil work effectively. I've tried a few others successfully as a test but I usually want to use something small in physical size with my model engines.
If you want to use your own coil, here's a few suggestions . . You want a coil with a winding ratio of 200 to 1 and a primary winding resistance of 1-2 ohms . . Generally speaking, the main wiring restriction is that your coils primary winding must be electronically separate from the secondary windings firing path and not be tied to ground. Some coils, including the one I sell, have internal wiring connections with 1 side of the primary winding and 1 side of the secondary winding tied common to the coils frame. The way in which the Buzz-Fire circuit generates the spark pulse requires that the primary windings not be part of the spark plugs firing ground return path. So if you have an engine with a coil with 1 input terminal only and the coils metallic frame is bolted to the engine block or frame, you'll need to figure out correct polarity and how to insulate that type of coil. The detailed assembly instruction I include show how to wire a coil correctly.
How do I test my circuit or coil ????
Or better yet, How do you NOT test your circuit . . DO NOT test your unit by seeing how far of a gap the spark will jump. When energized, the coil has a built up charge in the secondary windings and it needs to dissipate it somewhere easily. The larger the gap which the spark is trying to jump, the longer the charge is held in the coil until the energy buildup overcomes the resistance of the air gap. This creates excessive heat in the coils windings and will eventually lead to an insulation breakdown and shorting. The LED light is the best indicator. It only lights when the circuit is putting a signal into the coil. It should be bright each time the engine fires. If you are having a problem with your engine running, observe the LED. If it is inconsistent or dim, there is a spark problem.
First look for loose or improper wiring connections. Make sure your 6 volt battery is charged and the positive and negative leads are correctly connected. Is your On Off switch working ? Got 6 volts to the circuit ?
Now see if there is a spark . . .Use a known good spark plug with a .020-.025 gap to observe the spark. You should see and hear the buzzing.
WARNING !!! BE CAREFUL !! This is HIGH VOLTAGE !! It's not just one spark, It's multiple sparks and it hurts really bad if your fingers are in the firing path.
If you don't see a spark, next test your points or Hall Sensor. To bypass them, connect a wire directly to your battery negative terminal and touch the other end to input terminal 3. This should result in a firing pulse. If you now see a spark, your points or Sensor is causing the problem. If you feel the problem is in the Buzz-Fire circuit, the resistors and capacitors rarely cause problems, so it will most likely be the IC Chip or the transistors. I sell these 3 parts separately for $6 should you damage yours. Replace the IC Chip first as it simply plugs in. Then replace both transistors.
For questions or orders please email me - - - buzzfire@pacbell.net
Un-assembled Buzz_Fire kit . . . . . . . . . . . . $37.00 ( Coil not included)
Pre-assembled and tested as pictured above . . . . . $65.00
Hall Effect sensor and 1 magnet. . . . . . . . $ 3.00
Small Ignition Coil 1" X 2" . . . . . . . . . . . .$30.00
All shipping in USA via USPS . . . . . . . . . .$ 8.00
Here's My Pictures
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This page was last updated on May 15, 2009
