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-   1955 To 1957 Little Birds - General Technical Discussion (http://squarebirds.org/vbulletin/forumdisplay.php?f=61)
-   -   Gen Light w/1 wire Alternator (http://squarebirds.org/vbulletin/showthread.php?t=11239)

Jimz Bird 05-29-2011 03:33 PM

Gen Light w/1 wire Alternator
I stumbled on this today and it looks like it may provide a quick and fairly inexpensive ($18.95) way to have the Gen Light work for those who have installed a 1 wire Alternator.

It is just a voltage sensor that lights up the Gen light when voltage drops below 11 volts.

It probably could be made for about 1/3 the cost with Radio Shack stuff but still not a bad price.



simplyconnected 05-29-2011 09:57 PM

GREAT idea, Jim!

One drawback with the 1-wire is, if the engine starts but never revs, the alternator will NOT charge because there is no 'sense' wire to show the key is turned on.

If left for any time with the headlights or heater on, the battery will drop to 11-volts rapidly. Your new LED indicates, the alternator is not charging (and the engine needs to be rev'ed above 1,500-rpm to get it going.

If an engine throws a belt, this LED might 'flag' the driver before any damage is done.

Of course, the simple solution is to install a 3-wire alt, that way the GEN light will work the way you would expect.

A zener diode with a relay will indicate when the battery voltage drops below your preset.

NYsquarebird58 04-16-2012 11:39 AM

I was looking at the alternator conversion kit that Concourse Parts sells. I had some questions so I called and spoke with someone in tech support. I asked if the Alternator supplied was one wire and he said yes but he also said that the system is designed to work with the existing GEN light.

Dave gave me a good explanation on why 1 wire alternators are not a good choice, so that’s not something I want. But I’m wondering if this setup is different since it works with the existing GEN light. Maybe it somehow uses the existing ‘sense’ wire?

Jimz Bird 04-16-2012 01:00 PM


They may use the same type of device that I mentioned earlier. That is really not a "substitute" for a 3-wire. It is as Dave said probably only good to let you know a belt broke or that you need to rev your engine up.

I would ask them how that works with a one wire. It doesn't provide sensing just a warning.

Dave has covered this before and has wiring diagrams or you can go here to get a good overview of 1 wire vs 3 wire.

If you decide to use the GM alternator you can get a kit from Mark Hamilton on that site for either the CS or SI. They are about 10 bucks more than listed as the site prices are not updated.

Even with the kit and buying an alternator from the parts store you will be money ahead.

One thing I like about Mark's kits is that he includes good info and fusible link wires. They do need to have the butt splices and ring terminals installed on the wires but the instructions are good.

He also has a book "Electrical Wiring - Tech is Made Simple" for $8.95 that I would recommend that is VERY Good. It helped me to understand such things as "Thermal Runaway".

Another alternative is a Ford 3G alternator to keep it all Ford and follow Dave's wiring diagram.
Here is just one source for New not rebuilt alternators:

Here is an older thread that may be helpful:

Joe Johnston 04-16-2012 01:11 PM

A cosmetic benefit of using any internal regulated alternator is you can now remove the voltage regulator with its bundle of wires and clean up the engine bay!:cool:

simplyconnected 04-16-2012 02:49 PM

Marcello asked me to call Concours @ 800-722-0009. I spoke with Jay. He said the alt he sells IS a three-wire, 60-amp, GM type. He also said he knows he has brackets for a Y-Block but isn't sure about the FE.

If you are retrofitting to an alternator, get one that is big enough to run an electric fan. Some day you may install an electric fan or an electric water pump, etc.

Modern cars all have (electric fans and) alternators over 100-amps so I know bone yards are throwing them away every day.

Overcurrent protection is a "must have" on all alternators because alts use diodes that can short (at any time). It's like wearing seat belts... you may never need them but if you do, you want the best ones made. Fusible links work just fine, but are a little harder to find/replace than a fuse.

I really love to see all T-birds with modern alternators, and I don't care what brand you use. I don't like the one-wire type because it doesn't charge until rpm's go over 1,500, it gives no indication if you threw a belt, and it has NO way of using the GEN or ALT light. (Notice that none of the OEM's use it.)

That third little wire is a 'sense' wire and it directly connects to your GEN light wire. It senses that your key is on, it shines your GEN light until the engine runs, and it regulates your charging voltage. In short, it just works the way you would expect it should. - Dave

Joe Johnston 04-18-2012 10:32 AM

1 Attachment(s)
A cosmetic benefit of using any internal regulated alternator is you can now remove the voltage regulator with its bundle of wires and clean up the engine bay. This is a GM :eek: 3 wire alt I have used for several years and shows the less cluttered inner fender without the original 57 regulator. A double pulley let me retain the original generator mount and align the belt. When I changed to the 3 wire alt, it was not easy to get the gen light to work properly with a 1 wire system, so the new voltage sensor mentioned may solve that problem.

Not for everyone, but its what worked for me.

simplyconnected 04-18-2012 03:13 PM

Nice job, Joe. Nice car, too. I like lots of things you have going on, here. Your alternator looks like it belongs there. I don't see a fuse on it, but I hope you have one. (On all 1-wire systems, there is no place to connect a GEN light, so you lose that feature.*)

I like the headers on your Y-Block, and the stainless steel socket head cap screws that fasten them.

You Squarebird guys, take a look at Joe's top pivot shaft on his upper "A" arm. Notice that it is slightly longer on the back than the front. So, it must go back together the same way after changing bushings.

That's the reason for taking lots of pictures and marking your parts before disassembly.

* I like having a fat red GEN light. It lets me know right away when something is wrong. For systems where the water pump shares the alt/gen belt and it flys off, that GEN light will save your engine. By the time your gauge hits "HOT", your engine is already too hot. If a volt gauge drops below normal, it's already too low. Most drivers rarely look at the gauges, but an obnoxious idiot light quickly draws my attention BEFORE disaster strikes.

Joe Johnston 04-18-2012 05:48 PM

Thanks for the compliments! Routing the wires down along the round frame crossover tube hides the wires a bit too.

I drove the 57 for the first time today since Oct just before leaving for FL. It was awesome to hear that unique Y-Block sound again after 6 months. The SS cap screws made the installation much easier as a hex head bolt hit one of the tubes. Interestingly enough, when I had this engine rebuilt a couple of years ago, the shop called me and said they couldn't figure out how to remove those capscrews. I took a 1/2" length of allen wrench and a ratcheting box wrench to the shop and quickly removed them. I don't know if the shop foreman was was more embarassed or ticked off not being able to figure it out.

I always find the approach taken for modifications interesting and the upgrade to an alternator is a definite improvement. I tried to keep the original gen bracket for some reason, but at the same time wanted to make the original voltage regulator and all the jumble of wires on the inner fender disappear. Other guys want to keep everything except the generator and that works well too. Different strokes.............!

The headers were "aluminized" nearly 30 years ago and still look almost like the day I got them!

simplyconnected 04-18-2012 07:04 PM


Originally Posted by Joe Johnston (Post 64573)
...I tried to keep the original gen bracket for some reason, but at the same time wanted to make the original voltage regulator and all the jumble of wires on the inner fender disappear. Other guys want to keep everything except the generator and that works well too...

Very nice job, Joe. Why does everyone forget that Channellocks will turn a socket head bolt? The bolt heads are grooved for the jaws. I've often used an Allen wrench AND Channellocks to loosen bolts.

Stainless cap screws do far better than carbon steel bolts in exhaust applications because they don't rust or change head sizes. Yours look great after all that time (and heat cycles).

Everyone has a different restoration approach and I like that, too.

Some guys use the Voltage Regulator housing to put relays inside for running serious headlights. The power wire is already there from the Batt. It looks stock until those headlights come on. Relays lighten the load on the headlight switch, too.

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