The Ford Barn

tubman · 06-23-2017, 08:15 PM

Here's a post I recently made on the "H.A.M.B." Do any of of you guys have any interest in something like this?

"I have been disappointed with the availability of tachometers for 6 volt positive ground systems. There is not a good variety, and what's out there are very expensive. I was discussing this with a friend of mine last year and he said that with today's electronic components, it should be doable. It was, but it wasn't as simple as we first thought. We not only had to reverse the polarity and boost the voltage of the tach control logic, but we also found we had to do the same thing to the signal from the ignition system. After a winters work, my friend was able to come up with a neatly packaged solution that is "wire-up and go".

I have one on the '51 Mercury engine on my test stand and we also have two out being field tested on old GM pickups. Everything works like it should with no problems. I have included a video of the unit running on my test stand. I would like to apologize in advance for the quality of the video, but I am not the world's best "one hand" video guy. Here is that video on "YouTube" : https://youtu.be/TaxpuDkWAqc.

The video starts with the engine off, then I start it and let it run at idle for a few seconds. After I rev it a couple of times, I pan down to a shot of the driver unit itself (the black box) and then down to the 6 volt Optima battery. You can trace the cables back to see it is positive ground.

I believe that there is a decent demand for a unit like this among old car enthusiasts of all kinds. If there is enough interest, we plan on producing these for general use. Our problem is that since this is quite a complicated device, it must be built on a commercially produced circuit board to allow us to package it properly. This, along with the quantity discounts available on the required components, will cause the price to vary greatly depending on how many we make. We would probably have to make at least 300 of these to get the price down to where it would be reasonable. We would expect this to be between $50 to $100, depending on quantity. So, what do you guys think? Is this something that people want and will buy? Let me know.

By the way, my friend says that we could easily add an option that would allow us to drive old "meter-type" tachs with this. You know, the old Sun and Stewart Warner units that have a separate control box that either missing or not working. I don't have one of these, so we haven't tried it yet. Let me know about this as well."

06-23-2017, 08:15 PM	#1
tubman Senior Member Join Date: Dec 2013 Location: Minnesota, Florida Keys Posts: 12,140	12 volt tach on a 6 volt positive ground system Here's a post I recently made on the "H.A.M.B." Do any of of you guys have any interest in something like this? "I have been disappointed with the availability of tachometers for 6 volt positive ground systems. There is not a good variety, and what's out there are very expensive. I was discussing this with a friend of mine last year and he said that with today's electronic components, it should be doable. It was, but it wasn't as simple as we first thought. We not only had to reverse the polarity and boost the voltage of the tach control logic, but we also found we had to do the same thing to the signal from the ignition system. After a winters work, my friend was able to come up with a neatly packaged solution that is "wire-up and go". I have one on the '51 Mercury engine on my test stand and we also have two out being field tested on old GM pickups. Everything works like it should with no problems. I have included a video of the unit running on my test stand. I would like to apologize in advance for the quality of the video, but I am not the world's best "one hand" video guy. Here is that video on "YouTube" : https://youtu.be/TaxpuDkWAqc. The video starts with the engine off, then I start it and let it run at idle for a few seconds. After I rev it a couple of times, I pan down to a shot of the driver unit itself (the black box) and then down to the 6 volt Optima battery. You can trace the cables back to see it is positive ground. I believe that there is a decent demand for a unit like this among old car enthusiasts of all kinds. If there is enough interest, we plan on producing these for general use. Our problem is that since this is quite a complicated device, it must be built on a commercially produced circuit board to allow us to package it properly. This, along with the quantity discounts available on the required components, will cause the price to vary greatly depending on how many we make. We would probably have to make at least 300 of these to get the price down to where it would be reasonable. We would expect this to be between $50 to $100, depending on quantity. So, what do you guys think? Is this something that people want and will buy? Let me know. By the way, my friend says that we could easily add an option that would allow us to drive old "meter-type" tachs with this. You know, the old Sun and Stewart Warner units that have a separate control box that either missing or not working. I don't have one of these, so we haven't tried it yet. Let me know about this as well."