Considering Alternator Replacement, Weighing Options

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Considering Alternator Replacement, Weighing Options

December 10, 2023, 10:44:10 PM

The alternator in the thunderbird still currently works but is making noise and the threaded hole is stripped out so instead of rebuilding it and having other issues later(its pretty rusted up on the inside from sitting around for years) im just going to replace it. My wiring is in good shape no issues there.
Was looking for opinions on which path i should walk down here.

My current available options are the following,

A factory rebuilt nos 60 amp unit.
An upgraded output 1g external regulator alternator.
3g alternator upgrade.

The factory rebuilt one is old nos but is probably fine since it was just sitting on a shelf for years. Just bolt in and go. I cant remember if i had the 60 or 65 amp unit, and ofcourse i have pics of everthing else on the car i messed with except the alternator. Im not going with some parts store rebuild because of reputation and experience with them.

The upgraded output 1g alternators i find go up to 100 amps with 3 wire connections, without having to mess with new or cutting wires but are all in the 12/6 oclock position and would require the front part of case to be swapped. Sounds simple and was apparently common but i cant find a single example of someone doing this.

The 3g seems to be the most beneficial and gets recommended alot but i have a few caveats about doing this swap. Mainly its the wire cutting and possible bracket grinding. I really dont "need" 130 amps since im carbed and not running anything that isnt stock. Im considering a fan down the road but the upgraded 1g could handle this without all the snipping/adding wires and all that. The 95 amp ones would work without grinding but the rest still applies.
For such a common upgrade i couldnt find a single pic of a pre-86 v6 car with it, im sure they are out there but all the kits out are for 5.0 cars anyway.

I already have the nos one and a powermaster 7078, nothing for the 3g except some harness i could use if i had to.

Thoughts, opinions?

Re: Considering Alternator Replacement, Weighing Options

Reply #1 – December 12, 2023, 11:07:34 AM

The biggest determining factor for you will be the wiring. It will be worth your time to remove your old alternator and really, thoroughly inspect the wiring closely. The main connector at the alternator, especially, because any frayed connections there can cause a fire (and that's the reason why new alternators come with a new harness to splice in, to reduce that potential).

If your wiring looks good and you don't really antite running anything high power like auxiliary lighting or a big stereo system...I'd just run the NOS one (should be 60A). No fuss, no muss, plug and play, and be done with it. That will get the job done for sure.

In the past I have done an upgraded stock alternator before (70A), and that usually does require a little bit of work with the grinder on the bracket. The gains from this are minimal.

I also have a 130A upgrade on the convertible. It's been in place for almost 25 years, and aside from getting a couple of bad rebuilt alternators toward the beginning there, it's been rock solid. But also, that car has a big stereo plus the power top mechanism, upgraded lighting, etc. And I did do custom wiring for it. It was easy to do, no regrets, but the car is never going back to stock so I didn't care about that sort of thing.

Just my insight.

Re: Considering Alternator Replacement, Weighing Options

Reply #2 – December 12, 2023, 08:16:16 PM

My wiring appears to be fine, when i had everything apart for the belt tensioner swap i remember inspecting it some but just on the alternator end because i was working on that part of it. It was awhile ago ill have to double check.
The 3g swap doesnt allow me to retain the choke wire apparently and i would have to run a new one for it. Not really leaning towards it at this point anymore. My mustang convertible would probably benefit from a 3g upgrade but im not seeing much info regarding that for the 2.3l.

The upgraded 1g would make me want to put a better circut breaker/fusible link in place of the factory one but i dont see any difference in the wiring gauge for later cars with higher amp output, the charge wires and fusible links appear to be the same size for 3g powered cars stock harnesses ive been looking over.

I have off this thursday im going to try to pop over and pull the alternator out and see if i can swap the front part on the powermaster and see what happens. Going to have to dig up a decent multimeter to read amps but im sure i have one around somewhere.

Re: Considering Alternator Replacement, Weighing Options

Reply #3 – December 13, 2023, 11:05:35 AM

My 84 Ford shop manual has a detailed write-up of the 1G alternators.
Rear Terminal 40 & 60 amp. 8 Pages.
Side Terminal 70 & 100 amp. 7 pages.
I can scan and post the info if you are interested.

Re: Considering Alternator Replacement, Weighing Options

Reply #4 – December 13, 2023, 01:02:20 PM

Quote from: Ductape91 – on December 12, 2023, 08:16:16 PM

My mustang convertible would probably benefit from a 3g upgrade but im not seeing much info regarding that for the 2.3l.

It's not that different to install a 3G on a 2.3T than any other. You need a small case, 180* mount alternator and swap the pulley if you're keeping the dual belts.
I've had a 130A 3G on my TBird for years.

I put a 95A 3G on the LTS and would never consider another 1G, unless for some odd reason I was worried about originality.

Re: Considering Alternator Replacement, Weighing Options

Reply #5 – December 13, 2023, 06:19:25 PM

Quote from: softtouch – on December 13, 2023, 11:05:35 AM

My 84 Ford shop manual has a detailed write-up of the 1G alternators.
Rear Terminal 40 & 60 amp. 8 Pages.
Side Terminal 70 & 100 amp. 7 pages.
I can scan and post the info if you are interested.

I have some old book that talks about them from ford, its possibly the same info but post one to be sure.

Quote from: Chuck W – on December 13, 2023, 01:02:20 PM

Quote from: Ductape91 – on December 12, 2023, 08:16:16 PM
My mustang convertible would probably benefit from a 3g upgrade but im not seeing much info regarding that for the 2.3l.

It's not that different to install a 3G on a 2.3T than any other. You need a small case, 180* mount alternator and swap the pulley if you're keeping the dual belts.
I've had a 130A 3G on my TBird for years.

I put a 95A 3G on the LTS and would never consider another 1G, unless for some odd reason I was worried about originality.

I was worried it will stick into the distributor and ignition cables too much since its already kinda tight there. Hopefully not.

Re: Considering Alternator Replacement, Weighing Options

Reply #6 – December 13, 2023, 07:25:14 PM

The small case versions aren't any bigger than the 1G's.

Re: Considering Alternator Replacement, Weighing Options

Reply #7 – December 14, 2023, 12:48:13 AM

84 Ford Shop Manual 1g alternator rear terminal pics.

Re: Considering Alternator Replacement, Weighing Options

Reply #8 – December 14, 2023, 12:50:35 AM

More 1g pics

Re: Considering Alternator Replacement, Weighing Options

Reply #9 – December 14, 2023, 06:19:44 AM

Thats different than the book i got here.

Its mostly just a reference to the technician, the stuff you posted i probably have on the ebay service manual cd i bought awhile but am too lazy to pull out the computer for because its terrible for looking up specifics that way. Rather have the paper back ill get around to buying one at some point.

Re: Considering Alternator Replacement, Weighing Options

Reply #10 – December 14, 2023, 09:50:53 AM

Yeah, those manuals on CD are a pain to work with. I have to hang on to my Win XP computer to use them. They're a no go on Win 7-10.
I don't know if there is a visible difference between the 40 and 60 amp versions if the color stamps are not there.
In the text it says the stator coils are in a delta configuration in the 60 amp.
The side terminal shows the difference in the diagram.

Re: Considering Alternator Replacement, Weighing Options

Reply #11 – December 15, 2023, 12:00:42 AM

Quote from: softtouch – on December 14, 2023, 09:50:53 AM

Yeah, those manuals on CD are a pain to work with. I have to hang on to my Win XP computer to use them. They're a no go on Win 7-10.
I don't know if there is a visible difference between the 40 and 60 amp versions if the color stamps are not there.
In the text it says the stator coils are in a delta configuration in the 60 amp.
The side terminal shows the difference in the diagram.

I hear ya on the windows xp thing.

The only thing i know of how to tell is the stamp on the case for amp rating. My car has green and yellow paint on everything, including the alternator, for no reason so if i was looking for just that i wouldnt be certain of its rating.

The stamp on the nos one i got, it was under the sticker they put on it.

The color tag.

Re: Considering Alternator Replacement, Weighing Options

Reply #12 – October 26, 2024, 07:52:16 PM

did you ever decide?
i am converting both my 20th and my 1990 351w bronco.
I am unsure nowadays if anyone here has found an even larger ampacity alt in the same case size,, as in,, "shop for this xyz car" and you will have a bolt on unit.

I will be redoing the main wiring to #6 cause i have a bunch of that in rhh/rhw flex telecom rated & solder lugs and such.

Re: Considering Alternator Replacement, Weighing Options

Reply #13 – October 27, 2024, 11:27:02 AM

Quote from: jcassity – on October 26, 2024, 07:52:16 PM

did you ever decide?
i am converting both my 20th and my 1990 351w bronco.
I am unsure nowadays if anyone here has found an even larger ampacity alt in the same case size,, as in,, "shop for this xyz car" and you will have a bolt on unit.

I will be redoing the main wiring to #6 cause i have a bunch of that in rhh/rhw flex telecom rated & solder lugs and such.

Yeah, i went with a factory remanufactured stock 60amp 1g one in the tbird.
I figured the car is likely to stay bone stock so why bother.
I put the 100amp upgraded 1g into my mustang turbo convertible along with a nos harness for it.
I never got around to measuring current amps on the tbird at idle but the mustang pulled around 26 amps.