Gary Lewis Posted January 7, 2019 Share Posted January 7, 2019 On the choke, as it is an Edelbrock it will be 12v. But it can be run by the ~7v off the stator on the alternator, and that makes it pretty simple as you run a short wire. However, it takes longer for the choke to come off so you have to adjust the choke pretty lean. I'm running my Holley choke from the factory stator source. I didn't check it with my meter, but I understood it to be half of the ALT output voltage, so it *should be in the area of 7.25vdc? I know a 12vdc source is recommended, but there are a lot of Ford/Holley people that have used the factory stator source without issue. I read a thread on one of those hotrod forums where the guys tested/compared the two different voltage sources, and they claimed that the difference in time was negligible. Now, I know that's an anecdotal internet claim...but still, a lot of people do run them that way. I ran the Edelbrock on Rusty that way. It worked fine, but it was a bit touchy to set the choke as it didn't come off as quickly as it would have on 12v. But, it worked, and would be fine for at least testing, so that's what I'd do right now. What the actual voltage of the stator connection is escapes me. I tend to remember that the stator connection on a Ford alternator is a half-wave rectified output from one of the three windings. If so, then the voltage is actually half of a sine wave and will look something like this, although if it is 1/3 of the windings the blips will be further apart: The peaks will probably be something like 15 or 16 volts, and what a voltmeter will show you is an average of the voltage. And each DVM can have a different way to "average", so the results can vary. But the result is that you are getting something like 1/2 of the energy into the heating coil of the choke than you would with 12v. So it heats up more slowly and never gets as hot. But if you adjust the choke to accommodate that it will work - just not as cleanly as if it had 12v. Link to comment Share on other sites More sharing options...
Steve83 Posted January 7, 2019 Share Posted January 7, 2019 ...what a voltmeter will show you is an average of the voltage. And each DVM can have a different way to "average", so the results can vary.That's correct. For most AC Voltage waves, they oscillate above & below "ground" (0 Volts), so the simple mathematical "average" is 0 (not a useful number). So to produce a meaningful value, each instantaneous voltage is squared (which eliminates the negative) THEN averaged, and then the square root is calculated (which is the "Root Mean Square" formula). Most cheap DMMs are built to read AC Volts from household sources, which means they're only accurate at (or near) 60 Hz because they don't really do any calculation - they just guess, based on the assumption of 60Hz. A DMM labelled as "True RMS" (and it usually also reads Hz) is built to actually measure the frequency, and then calculate ACV correctly. So it will accurately respond to varying frequencies of ACV, like the alternator of a revving engine (or a generator ). https://supermotors.net/getfile/1077817/thumbnail/rs22172dmm.jpg Link to comment Share on other sites More sharing options...
Ferdinand Posted January 8, 2019 Author Share Posted January 8, 2019 ...what a voltmeter will show you is an average of the voltage. And each DVM can have a different way to "average", so the results can vary.That's correct. For most AC Voltage waves, they oscillate above & below "ground" (0 Volts), so the simple mathematical "average" is 0 (not a useful number). So to produce a meaningful value, each instantaneous voltage is squared (which eliminates the negative) THEN averaged, and then the square root is calculated (which is the "Root Mean Square" formula). Most cheap DMMs are built to read AC Volts from household sources, which means they're only accurate at (or near) 60 Hz because they don't really do any calculation - they just guess, based on the assumption of 60Hz. A DMM labelled as "True RMS" (and it usually also reads Hz) is built to actually measure the frequency, and then calculate ACV correctly. So it will accurately respond to varying frequencies of ACV, like the alternator of a revving engine (or a generator ). https://supermotors.net/getfile/1077817/thumbnail/rs22172dmm.jpg This is all I have by way of metering: I don't think any of these say true RMSÂ Link to comment Share on other sites More sharing options...
Gary Lewis Posted January 8, 2019 Share Posted January 8, 2019 ...what a voltmeter will show you is an average of the voltage. And each DVM can have a different way to "average", so the results can vary.That's correct. For most AC Voltage waves, they oscillate above & below "ground" (0 Volts), so the simple mathematical "average" is 0 (not a useful number). So to produce a meaningful value, each instantaneous voltage is squared (which eliminates the negative) THEN averaged, and then the square root is calculated (which is the "Root Mean Square" formula). Most cheap DMMs are built to read AC Volts from household sources, which means they're only accurate at (or near) 60 Hz because they don't really do any calculation - they just guess, based on the assumption of 60Hz. A DMM labelled as "True RMS" (and it usually also reads Hz) is built to actually measure the frequency, and then calculate ACV correctly. So it will accurately respond to varying frequencies of ACV, like the alternator of a revving engine (or a generator ). https://supermotors.net/getfile/1077817/thumbnail/rs22172dmm.jpg This is all I have by way of metering: I don't think any of these say true RMS I wish I had some that said Fluke! I'm impressed. Link to comment Share on other sites More sharing options...
Ferdinand Posted January 8, 2019 Author Share Posted January 8, 2019 Thanks for the compliments on the Coffee Table. Link to comment Share on other sites More sharing options...
Ferdinand Posted January 8, 2019 Author Share Posted January 8, 2019 I wish I had some that said Fluke! I'm impressed. This guy comes in crazy handy too! Link to comment Share on other sites More sharing options...
Ferdinand Posted January 8, 2019 Author Share Posted January 8, 2019 Read the carb manual to be sure, but I think I can almost make out "12V" molded into the heater in your last pic. If it's 12V: since this is such a low-current addition (probably ~1A or less), it's safe to add it to a much-higher-current factory circuit (one with a 5A or higher fuse). Through the factory firewall grommet, inside the factory harness. Use a semi-blunt probe (like a long phillips screwdriver) to spread the wires inside the grommet, and feed your new wire(s) through before they shift back into place. Thanks for the info and suggestions. I am going to go ahead and wire it to a 12v source like you and Gary have eluded to. I think with the trouble shooting I am under, the less variables to contend with the better. I keep getting out to the garage too late now to run this thing without waking my family (and the neighbors). I need to get it running well enough to get the exhaust put on so I can run it a bit more!! Now that I'm thinking of it, I may flat bed it over to the muffler shop (it's only 4 miles away) and have them put the exhaust on it so when I can bring it back I can tune on it a little later in the evenings. 🤔 Link to comment Share on other sites More sharing options...
Rembrant Posted January 8, 2019 Share Posted January 8, 2019 What the actual voltage of the stator connection is escapes me. All I knew was that it was supposed to be about half of what the typical output voltage would be (14.5vdc). According to my 1984 FSM: Interesting to note, I kept coming across mentions of a full 12vdc choke. You can see in the chart above. It was done with battery voltage through and oil pressure switch. That would be a nice way of doing it if you were running a full 12vdc...although it would require an extra oil pressure port. One of the reasons I personally stuck with the factory 7.2vdc was that I wanted a run-only signal. I can guarantee you that I'd be that guy that left the key on at some point and baked the element...lol. Now, if I had an easy place to install and oil pressure switch....hmmm... Link to comment Share on other sites More sharing options...
Steve83 Posted January 8, 2019 Share Posted January 8, 2019 Now, if I had an easy place to install and oil pressure switch...Extend the stock sender away from the block, and add a common plumbing T. Link to comment Share on other sites More sharing options...
Gary Lewis Posted January 8, 2019 Share Posted January 8, 2019 Thanks for the compliments on the Coffee Table. My oldest doesn't care much for wrenching, but she regrets that I set down the construction company 😉 You do your woodworking outside? And what does "set down" mean? Sold? As for the IR thermometer, I have a Chinese version. So cheap that recently the plastic trigger folded. But it was hollow and I straightened it out, put it in the vise, and filled it with hot glue. Once that set up it was better than new. But, the IR thermometer is extremely handy. Link to comment Share on other sites More sharing options...
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