MSefi.com read only forum (Jan.15,2018)

I am in need of a circuit that will boost the output of the kill wire on a Vertex magneto. when the mag gets hot (engine block temp) it quits triggering the opto-isolater. It worked while the engine was in the open air but when the body was installed and I was able to drive the car three years ago, this problem came up so I had to change to a modified Accel distributor.
This is MS v3.000 and v2.2 board. Also this is the '57 Corvette chassis I brought to the first MegaSquirt meeting at Kensington Park in Michigan.

Is there a tach adapter available for this?

I don't think there is because I always got the tach signal from the same wire when I was using carbs but I did not use a tach and the MegaSquirt at the same time. I have not seen an optional device for a Vertex other than a relay that grounds it with the ignition switch. I was looking at using an HEI 990 firing module but nothing comes to mind.
Dennis

Matt,
Did I miss understand your question about a tach adapter?
Dennis

I was thinking of using one of these:

http://www.autometer.com/cat_accessorie ... spx?vid=98

Do you have any information on what the signal on that wire looks like? Is it a square wave, voltage spikes off the coil, or what?

My mag is one piece (no external coil), so that module won't work according to autometer and a couple of forums I checked. I do know that terminal can bite if you touch it. I'll set the mag up on the bench and run it with a drill motor and see if I can get a volt reading and, I hope an o-scope pattern. Not experienced in using an o-scope. I can find no specs on this magneto on the web.
Thanks.

This what I did. I set the magneto up on my distributor machine and tested it for DC volts and AC volts. Ran the mag slow to simulate cranking and got .002 to ~1.15 erratic volts DC. as I sped the mag up, the voltage hung in at around .07 volts DC. The AC numbers were - slow ~3.5 volts AC and as I sped the mag up, the volts climbed to 17 AC. I also tested the Ohms at the kill terminal and the case and got 0.7 with points open and 0.3 points closed. I took a video of the O-scope pattern but this site won't let me send it or I don't know how to send it.

How do I upload a video? I'm going to try again. Nope, it won't do it. Says "connecting" for a while then I get a new "post a reply" page. It's a ".mov file.

.mov files are not an allowed attachment type. Easiest way to attach would to link a file from youtube or a photo site.

Thanks Kholman. I hope I do this right. http://www.youtube.com/watch?v=OLWw4sO5Omo It works! That was interesting. I learned something new! This, I hope, will get some one interested in what I'm up to with this car. Thanks again for the education!