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I am currently looking at doing the 3g alternator upgrade for my 70. However when looking into this I saw that they have 3g alternators that are also one wire.

Has anyone done the one wire alternator?

Are there any reasons not to do the one wire 3g vs the harnessed 3g?

one thing I was reading was, if you did the one wire, that you won’t have the “dummy” light work on the dash.

Thanks in advance.

 

I did a 1-wire, and it was very easy. However, people claim to have issues with when the charging initially kicks on (at a higher RPM than the now traditional 3G style), but honestly I haven't had an issue. I got mine through Summit Racing, and it was cheaper than getting a 3G set up because there are not a lot of pick-and-pulls near me. The dummy light won't show up, but I wired a voltmeter to replace the old ammeter anyway, so it's irrelevant anyway.



I ran the ground to the battery. The ground on the battery goes right to the engine, and the alternator ground is on top of it. It's recommended that you use a direct engine ground, but it works the same.



Hot wire is run through a 100 amp fuse before hitting the battery. All the original voltage regulator stuff needs to be disconnected.

 

You could get a 10si, 3-wire, which is what the one-wire is based off of. The 3-wire would allow you to keep the alt light.

 

If you are doing a 3G alternator swap, I strongly recommend a two groove alternator pulley. I purchase one for and F600 for $26. Prior to installing the two groove pulley my high compression 390 starter would get heat soak, and I would have to wait for it to cool down. Upon restart the current draw was high due to the extra current needed to turn over the motor, and the alternator belt would slip and squeal on startup. My water pump pulley had two grooves one for alternator and one for power steering. I used the two water pump grooves for the two groove alternator and used the 3rd groove on the crank pulley to run the power steering (there is more belt contact one the power steering belt now so I get not power steering squeal at all).


Yes I know the ground is red, it was just so much cheaper that a black cable the same gauge and length.
On a side note, the belt lengths need to the exactly the same. I got one belt for a part store that starts with and "A" (we have three different ones). The store I bought it from only had one belt, but the said another store in the area had the same belt. Went a purchased that belt from a different location, exact same part number and brand but the belts were different lengths, not much but would not work. So I said lets try one that is 1" longer, again they only had one, but another store and one, those two belts were also different lengths (same exact part number and brand). Six different parts store and still different lengths. I believe a different batch varies slightly in length, so I ordered two FVP belts from rock auto and they are exactly the same length. Lesson learned, if you need belts that are exactly the same length, get them from the same batch.

 

Did you run a spacer behind the pulley?

I started the 3g swap last night on mine and I pulled my dual pulley off my 1g and I wouldn’t work without a spacer behind it and then would only catch a couple threads on the nut.

 

Yes there is about a 3/8" more or less between pulley and alternator spacer .

 

This is the pulley I ordered
https://www.ebay.com/itm/335835977210

It has quit a bit of recess to the nut for the pulley.

 

It won’t let me see it.

I ordered a pulley last night.

I need to take one of the alternators in and have it tested. I was clocking them last night and went through two of them. They were junk yard ones and I think we’re just so corroded.

 

I updated the link, hopefully it works.

 

Okay that’s essentially the same one I purchased.

hopefully this concoction of and alternator that I pieced together will work and I’ll be good to go.

 

I did make a thin spacer when I did my 3g swap. My truck had the ammeter, so it got converted to a volt meter from Rocketman.

 

You need to go find a matched set, they do make matched sets of belts. I know from installing them on industrial engines. Two of the same part number will not be the exact same length. The matched sets are only sold in pairs, probably better to check an industrial supply place once you know the size you want.

 

Thanks for that insight Turbo, I did not know that about matched set belts. As for the pulley, I used my original off my old Alt and put it on the 3G from a Taurus.

 

I swapped out the stock type alt on my 66 for a 3g 95amp model. I think it was 3 wires and a jumper. I don’t get the fasciation with one wire alternators. Mine is stock for some kind of Taurus or something so easy to get and cheap if I need to replace

even running the stock type alt, I got this compact voltage reg that bolted onto the back of the alt, thus turning that one into a “one wire” and eliminating most of the factory VR wiring

 

In all honesty I’m about as sharp as a spoon so forgive me if this seems dumb but I just want to make sure I’m doing this right.


I was going to remove this piece from my old harness so I had a plug that could attach to the harness on my fender and still have my horn.
[img alt="The green red wire would attach to the green red wire through this plug.

I would need to attach a 500-560 ohm resister on this wire correct?"]https://cimg4.ibsrv.net/gimg/www.ford-trucks.com-vbulletin/2000x1504/img_9094_ae0bcf7f6e79ed971b0a3101b6f5c5540880d770. jpeg[/img]
The green red wire would attach to the green red wire through this plug. I would need to attach a 500-560 ohm resister on this wire correct?


The other wires I am good with since they both go to the hot side of the solenoid on the fender.

Will my dummy light still work on my dash or no?

sorry I know there is a myriad of articles and posts on this but just kind of confusing me.