3G Interchange Facts. If you're thinking 3G, read here.

[Clarko]

PLEASE READ THIS ENTIRE POST BEFORE ASKING QUESTIONS!!!

Had to start this thread since there is much misinformation and confusion about the 3G alternator upgrade. This is not an install thread, just a guide on where to get the alt you need, a wiring diagram, and pulley sizing. All photos and some of the text is courtesy of Ryan at FordFuelInjection.com.


There are 3 different mounting styles for the 3G alternator that can be used as an upgrade on other vehicles:


If you have a 65-86: or anything with v-belts, you'll need a Pivot Mount w/ 8.25” ear spacing alternator. Some 90, any 91-92, and some 93-99 non DOHC Ford Taurus will be able to donate it's alternator to your truck. You may also be able to use one that fits the 87-92 serpentine setup (Pivot Mount w/ 7.00” ear spacing) on your v-belt truck but some may have fitment issues with smog pump location. The Pivot Mount w/ 8.25” ear spacing can be swapped into:
1965-1986 V-belt Mustangs
Other V-belt vehicles that can adjust to an 8.25” wide Pivot mount alternator

A wide-eared Taurus alt will ONLY fit a 302 or 351W if it is a V-belt setup since it's wider than a serpentine one.

Comparson between Narrow-Eared and Wide-Eared:


The following only applies to a 302 (5.0) only!
If you have no external regulator: you have a 2G alternator. This is an early serpentine style. This can only be replaced with a Pivot Mount w/ 7.00” ear spacing alternator. Minor bracket clearancing may be required. This can be found in the following cars:
93-99 narrow-eared non-DOHC Taurus
94-95 V8 Mustang
94-00 V6 Mustang
94-97 V6 T-Bird/Cougar
95-98 Windstar
91-94 V6 Lincoln Continental.
The early serpentine car and truck alts on Ryan's site are interchangable but the plug and charge stud are clocked differently to fit the wiring to the bracket better. The Pivot Mount w/ 7.00” ear spacing can be swapped into:
1965-1995 Mustangs
Other vehicles that use a 7.00” wide Pivot mount alternator
It looks like this:

Clearancing the stock bracket to fit a large case 3G:

Pic courtesy Helmut Roner.

A side mount alternator will not fit any 1965-1995 Mustangs.

Here's a great way to tell the difference between a 95A and a 130A:


You can also get 160 amp alternators, with NO core charge and cheaper than a new 130, from Ryan right here.

Plug Clocking: Each style may have the rear plugs clocked 3 different ways to fit their various vehicles better. They will still fit no matter the clocking but you can remove the case bolts, and reclock the rear to get your optimum position.



Charge Cables: When you swap from a 1G or a low output 3G to a 130 or more amp 3G, although you do not NEED a larger charge cable such as a 2 Gauge, it is a great idea. Smaller wires/cables cannot always handle such a load and they tend to heat up, some to the point of melting the wire and could start a fire. ALWAYS make sure you use a megafuse rated at above your alternator amperage.

Pulleys: For pulleys, you can either re-use your old one, which sometimes you may need a very small washer to use as a spacer if it rubs in the 3G case at all, or you can get a different sized one. It all depends on your needs. A smaller pulley will spin the alternator faster at idle to create maximum output. A larger pulley will allow the engine to rev higher without driving the alternator to fast. Large 3G alternators are safe to ~15,000RPM max. Alt RPM = Engine RPM x Alt Pulley Diameter ÷ Crank Pulley Diameter.

Wiring Diagram:

You can make your own or buy a complete one from here: http://oldfuelinjection.com/index.php?p=67

Factory Carb Users:
If you have a Factory Ford carburetor (Holley model 4180) with a wire that connects directly to your 1G alt to your electric choke, get a 12 volt electric choke for a Holley 2300/4150/4160 and swap it out. Then wire the new choke to 12 volts from any wire that is hot when the key is turned to run.

This post will continually be edited as information pops up. Please post any errors you find so this can be THE thread for 3G interchange information.

Versions of this thread are also hosted at:
Full Size Bronco.com:
http://www.fullsizebronco.com/forum/...ad.php?t=55169[/b]

[pextor]

lots of good info. i never realised the taurus/sable used two different alts.

is there any way to tell what taurus has a wide-ear versus narrow, like different years or 3.0 versus 3.8?

[Clarko]

lots of good info. i never realised the taurus/sable used two different alts.

is there any way to tell what taurus has a wide-ear versus narrow, like different years or 3.0 versus 3.8?

Honestly, 96-99 were the only years you could ger a narrow-eared alt. They were on some 3.0s only. There were 3 different 3.0s, one was DOHC and easy to rule out.
The pic above is what a narrow eared alt looks like.
This is what a wide eared alt looks like with the exception of the pulley:

You can see the mounting tabs' differences.

[mfpmax]

http://www.pa-performance.com/8693.asp They show the two versions as well.

[Clarko]

http://www.pa-performance.com/8693.asp They show the two versions as well.

Nope, that's the 135mm (small case 3G) and the 148mm (large case 3G that I'm talking about here) next to each other. The small case 3G is worthless.

[pextor]

so the 86-95 taurus alt is guaranteed to be a wide-eared?

[mfpmax]

http://www.pa-performance.com/8693.asp They show the two versions as well.

Nope, that's the 135mm (small case 3G) and the 148mm (large case 3G that I'm talking about here) next to each other. The small case 3G is worthless.

Work on mine I bet I believe the large case 3G is too big for 2.3 EFI cars with certain brackets. Don't forget about the little guys now.

[Clarko]

The spacing between the mounting holes are the same!
If you need to grind the brackets, do it.
You have to grind the bracket on 87-92 F-Series and Broncos

[Clarko]

so the 86-95 taurus alt is guaranteed to be a wide-eared?

No. 93-95 3.0s have the narrow-ear spacing.

[IWL BCNU]

On my Bronco board we had a big debate on the mega fuse usage and it seemed not needed as it didn't really protect anything. What's the verdict here?

Basically, the fuse protects the batt if the alt goes bad, but in reality if the alt went bad, it would blow internally before blowing the fuse.

[Daggar]

On my Bronco board we had a big debate on the mega fuse usage and it seemed not needed as it didn't really protect anything. What's the verdict here?

Basically, the fuse protects the batt if the alt goes bad, but in reality if the alt went bad, it would blow internally before blowing the fuse.

The only thing that the fuse really protects against is an internal alternator short. Since 3Gs are internally regulated then having that fuse isn't a bad idea at all.

As far as the wiring goes: Having wire sufficient enough to carry the full rated output of the alternator is always a good idea. However, putting a 3G alternator into a car with all stock accessories is not going to increase the load on supply wiring. Only the current that is being used will be carried through the wiring. It's the folks that attempt to run accessories such as electric fans etc., through the stock gauged wiring that end up with trouble.

[Clarko]

On my Bronco board we had a big debate on the mega fuse usage and it seemed not needed as it didn't really protect anything. What's the verdict here?

Basically, the fuse protects the batt if the alt goes bad, but in reality if the alt went bad, it would blow internally before blowing the fuse.

Which Bronco board are you on?

The fuse DOES NOT protect the battery, it saves the car from going up in flames! My original 2G in my Bronco got a short and caught the alt harness on fire. LUCKILY, the fusible link blew otherwise the system would have kept sending power and increased the heat on that wire and could have made a huge fire which would have screwed me over.

ALWAYS run a fuse, no matter what!

[Clarko]

As far as the wiring goes: Having wire sufficient enough to carry the full rated output of the alternator is always a good idea. However, putting a 3G alternator into a car with all stock accessories is not going to increase the load on supply wiring.

Yeah but, why not go above and beyond the needed capacity so there's room for upgrade later? Also, if you haven't maxed out the stock alternator/wiring, there's no need for a 3G.

[frankiesaysrelax]

so the 86-95 taurus alt is guaranteed to be a wide-eared?

Yes.

That's odd. I have a 130 amp 3G from a '93 Taurus 3.0 and I believe it looks like the narrow eared kind. I know it fit just fine in the box that a standard 2G Mustang rebuilt alternator came in, even with all the extra fat gauge wire I cut from the Taurus harness still attached. I'd have to go to my storage area and dig it out, but I'd swear it is the narrow eared kind. It even has a nice "130 AMP" sticker on it.

[Daggar]

As far as the wiring goes: Having wire sufficient enough to carry the full rated output of the alternator is always a good idea. However, putting a 3G alternator into a car with all stock accessories is not going to increase the load on supply wiring.

Yeah but, why not go above and beyond the needed capacity so there's room for upgrade later? Also, if you haven't maxed out the stock alternator/wiring, there's no need for a 3G.

I agree. Personally, I wouldn't install a larger alt without upgrading the wiring just in case of a short. As for there otherwise being no reason... well... better charging at idle is one reason someone might upgrade.

[accidentprone86]

I read everything and i am kind of confused.
i looked at the site and i plane on ordering a 3g conversion from them.
I know i need the serpentine 160 amp 3g alt. What else do i need? How do i wire it up? the site wasnt very clear.
I have my stock 86 5.0 setup in there now.
Also it says the alts come threaded and with a bolt. This means it will bolt right up, Right?

Thank you for posting the information. They have really good pricing.

[Daggar]

I read everything and i am kind of confused.
i looked at the site and i plane on ordering a 3g conversion from them.
I know i need the serpentine 160 amp 3g alt. What else do i need? How do i wire it up? the site wasnt very clear.
I have my stock 86 5.0 setup in there now.
Also it says the alts come threaded and with a bolt. This means it will bolt right up, Right?

Thank you for posting the information. They have really good pricing.

Wiring is pretty simple. Pickup a 3 wire pigtail from your favorite retailer (PA-performance has these) or wire up your own. 86s are missing the stator wire from the 3 wire plug since they (2Gs) are internally excited. Match the other colors from the pigtail to the colors in your regulator harness and solder them (you can crimp them but it's kind of half-ass). You need not modify or use the two wire power plug. Pull it, and tie it up out the way. Run a 4 gauge wire from the alt power post to the unswitched side of your fender mounted start solenoid. Install an inline 150 or 200 amp fuse block (depending on the amount of current draw you plan to pull or the rated output of the alt). and whola. You're done. Any accessory being fed by the now unused 2 wire 2G alt plug, will be fed from the other end of that particular harness and you're still backward compatable with the 2G if you ever needed to be. If you like: You can strip that harness down and cut out the wires back to the splices and get rid of it (talking about the two black/orange wires here).

[Clarko]

so the 86-95 taurus alt is guaranteed to be a wide-eared?

No. 93-95 3.0s have the narrow-ear spacing.

That's odd. I have a 130 amp 3G from a '93 Taurus 3.0 and I believe it looks like the narrow eared kind. I know it fit just fine in the box that a standard 2G Mustang rebuilt alternator came in, even with all the extra fat gauge wire I cut from the Taurus harness still attached. I'd have to go to my storage area and dig it out, but I'd swear it is the narrow eared kind. It even has a nice "130 AMP" sticker on it.

Sorry 92 was the same body style and does have a 8.25" spacing on the 3.0. A 93-95 3.0 has 7.00" spacing!

[frankiesaysrelax]

so the 86-95 taurus alt is guaranteed to be a wide-eared?

No. 93-95 3.0s have the narrow-ear spacing.

That's odd. I have a 130 amp 3G from a '93 Taurus 3.0 and I believe it looks like the narrow eared kind. I know it fit just fine in the box that a standard 2G Mustang rebuilt alternator came in, even with all the extra fat gauge wire I cut from the Taurus harness still attached. I'd have to go to my storage area and dig it out, but I'd swear it is the narrow eared kind. It even has a nice "130 AMP" sticker on it.

Sorry 92 was the same body style and does have a 8.25" spacing on the 3.0. A 93-95 3.0 has 7.00" spacing!

Ok, so the '93 alternator I have should be the correct one? Thanks.

[Clarko]

so the 86-95 taurus alt is guaranteed to be a wide-eared?

No. 93-95 3.0s have the narrow-ear spacing.

That's odd. I have a 130 amp 3G from a '93 Taurus 3.0 and I believe it looks like the narrow eared kind. I know it fit just fine in the box that a standard 2G Mustang rebuilt alternator came in, even with all the extra fat gauge wire I cut from the Taurus harness still attached. I'd have to go to my storage area and dig it out, but I'd swear it is the narrow eared kind. It even has a nice "130 AMP" sticker on it.

Sorry 92 was the same body style and does have a 8.25" spacing on the 3.0. A 93-95 3.0 has 7.00" spacing!

Ok, so the '93 alternator I have should be the correct one? Thanks.

Yes, it'll work. Sorry, my bad.

[frankiesaysrelax]

Ok, so the '93 alternator I have should be the correct one? Thanks.

Yes, it'll work. Sorry, my bad.

Ok cool! :breathes a sigh of relief:

Do you know a good place to score one of those regulator/brush assemblies that screws onto the back of the alternator. My brushes don't look like they have a lot of life left. For free I can't complain, but I would like to freshen it up a bit before I install it.

[Clarko]

Right Here from Ford Fuel Injection
I'd do the bearings at the same time, too, since they're only $10.

[frankiesaysrelax]

Right Here from Ford Fuel Injection
I'd do the bearings at the same time, too, since they're only $10.

Cool, thanks.

[IWL BCNU]

On the Classic Bronco board. It was argued that before the 200amp fuse would blow, the alt would fry itself internally before burning the wiring.

[Clarko]

On the Classic Bronco board. It was argued that before the 200amp fuse would blow, the alt would fry itself internally before burning the wiring.

175 amp.