Exchanged emails with Spud from Fuel Injection today. I'd prefer to use his magnetic trigger, but my electronic tach can''t be set for 3 cylinders (it is an inline six) but with this product you have to configure your tach for 1/2 the number of cylinders due to the number of pulse per rev that it generates.
Yep "P" stands for "Primary winding". To kill the maggie, you earth the primary windings. Once earthed, they cannot flicker power on/off, and their magnetic field is thus constant. No flickering magnetic field means no voltage induced in the secondary windings, and hence no zap at the plugs. cheers, Harv
Since the converter is the same one that Autometer sells I reached out to them, while I'm waiting to hear back from Joe Hunt's tech guy. They tell me that this converter will not work with the Vertex OAC, but I swear I checked this out before I bought the converter and electronic tach. I also spoke with a Spud Miller from Fuel Injected that sells a Hall Effect sensor for the Vertex magneto, but since it sends two pulses per revolution, you need to setup your tach for 1/2 the number of cylinders you have in order to get an accurate reading. The problem is that the electronic tach I have will not allow me to configure it for three cylinders.......
Thank you for sending me the direction of Spud Miller at Fuel Injection. He has been incredibly patient with my flurry of emails describing my situation. He's convinced me that with his suppression wires, I can make use of the Joe Hunt/Autometer tach signal converter. However, in the process I convinced myself to make use of the Hall Effect sensor that he sells at Fuel Injection that attaches directly to the Vertex tach itself. He didn't up sell me, I up sold myself. I'm already going to be using a Hall Effect sensor that screws into my GM 4-speed manual transmission where the mechanical speedometer cable used to be. As a result, I'm more comfortable with that approach rather than the black box converter with too many wires to figure out in my application. The thing that Spud had to get through my thick head was that the magneto hall effect sensor detects three pulse (every other contact in a six cylinder engine) and because the magneto runs at 1/2 of engine speed, the sensor produces 1 1/2 pulses per engine rotation. Since you can't actually detect 1/2 of a pulse, it means that when there are six pulses, the engine has rotated twice. Since I have an electronic tach that doesn't have a setting for a three cylinder engine, I'm getting an estimate from the gauge manufacturer to modify the software in my tach to match this set of sensor pulses (six pulses equals two RPM's). If this sounds confusing, it was for me, but I think I've got it now. On to the next set of problems/issues/opportunities in my rebuild project.
What is the Hall effect sensor reading off? Can you modify the sensor detection point (normally a shutter or series of notches) so that you get the required number of pulses per revolution, but use the same sensor? Cheers, Harv
Most all electronic tach manufactures sell Mag adapter . I had one on a VDO for a few years . My OT Power Wagon has a tach sensor terminal , from the stator windings on a GM 12 SI alternator , but it requires a tach designed to be used in the fashion.
As I understand it (as I take a deep breathe...) there are magnets attached internally for every spark plug wire terminal. They alternate North South, so my six cylinder magneto has three north and three south magnets that are rotating. The sensor placed in an exact location, senses each north facing magnet, thus for each rotation of the magneto it senses the north magnet three times. Since the magneto rotates at one half of engine speed, that means that for each rotation of the engine, the magneto has only rotated half way (meaning 1 1/2 north magnets). Since you can't sense 1/2 of a magnet, you need a full rotation of the magneto to sense the north magnet three times, but that is two full rotations of the engine. So my tach gauge company is going to alter my tachs internal software to recognize that three square wave pulses equals 2 RPM. Here is the install sheet and instructions (mind you the four they are referencing in the do***entation is for a typical V8 engine/magneto combination) http://fuelinjectionent.com/library/FIE-Tach-Pod-VERTEX.pdf PS. Spud is a very patient man, it took me a while today to fully grasp all of this and communicate it to the gauge company properly.
The magneto is winging its way to Spud as of this afternoon for installation of the hall effect sensor and the tachometer is on its way back to New Vintage USA (gauge manufacturer) for a software update to translate the number of pulses from the sensor into the correct RPM. Based on what I was told from both groups, I might have them back by the end of nest week. Pics and description of results to follow......
[QUOTE="Bob Kirk, PS. Spud is a very patient man, it took me a while today to fully grasp all of this and communicate it to the gauge company properly.[/QUOTE] That explains why I was unable to reach Spud on the phone today
the a Joe Hunt magneto I have 261 Chevy 6 in '54 Bel Air 2dr post sedan and have run it years using the same type of Joe Hunt magneto, got a Hunt Tach Converter hid it inside of old Sun Tach sender unit mounted mounted on the inner fender panel... 916) 635 5387 www.huntmagnetos.com Dyno Dave
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