STICKY: 3G Interchange Facts. Read if you're thinking 3G

[zergyo-71]

Hello bump fans, just wanted to let you guys know that the other day my starter died, so I thought, might as well upgrade my charging system. I read this thread and thought, why not? First, I had to find an alternator, so I made a phone call to a buddy of mine and luckily for me, he had two new remanufactured alternators off of a Taurus that he had for over a decade. Being the good friend that he is, he gave me both of them and said, "Try one and if it works, then you'll have a spare!" I started the upgrade yesterday and finished it today, about 5 hours worth total. The time consuming part was looking in my garage for cables. I'm a pack rat and just KNEW that I had stuff that I could use somewhere in there. Well, I did find a harness that came off a late '90's F=150 which worked great. It had the right connectors for the alternator and the fusible links going to the battery. I just need to shorten it up, 'cause it's too long. I used a positive battery terminal from a newer F-150 and it looks cool.
I started the truck and at idle it's reading 13.4V, with the lights and the electric fans on. I'll check how many amps is putting out tomorrow. It's already better than the 12.8V stock that was putting out with no loads on. When I beautify the wiring mess, I'll take some pics and hopefully figure out how to post them....by the way, don't forget that you can clock your alternator three different ways...I had to do that so that the connections were sitting on top, instead of right next to the exhaust manifold.
Godspeed to you all!!!

[FomocoLoco72]

Im very new to this site but have owned my 72 F100 w/390 for about 20 years now. I just wanted to expand this topic a little more with something I found that might be easier. Just bought a camper and decided to get the truck into long haul shape. To make a long story short, I too went the electric fan route. Which everyone knows pushed my alt past its limits. Im an import guy and happen to work on SAAB's, so I have a lot of parts laying around from 25+ years of work. When I took the old alt off I noticed it looked really close to the ones Saab uses (Bosch) and just had the mounting tabs offset a little. Saabs alts mounts are at 12 o'clock and 5 o'clock. These are one wire alts and dont require all the mods to make them work. I used one from an old 900 thats 80 amps and it bolted right up. So I tried another 130 amp off a later model 900/9-3/9-5, it too bolted right up but I had to clearance the lower bracket and alt case slightly. The best part is these line up perfectly with the crank pulley and the old 900 stuff (84 to 93) already has a double v pulley and wont require any mods (grinding) at all to bolt up. So all you have to do is use the resistor wire from the old voltage regulator to enable charging and add a new larger gauge wire from the alt to the solenoid. I swapped the double v pulley from the old Saab alt (84-93) to the newer style (94-on) and bolted it right up. The only issue I had was this truck has PS & AC and I couldnt find a cheap belt long enough to wrap the second outer belt around the alt/crank/water pump and PS. So I just found a shorter belt (975mm) to wrap around the inner most pulley so it is driven ONLY by the crank and no longer wraps around the water pump. This extra bit of belt contact eliminated any belt squeal issues and it only required one different belt from stock. Which should make servicing much easier. I now have 14 volts at idle with lights, fan and everything running. I know everyone may not like this idea, but it was much easier than a 3G conversion. (I have done those 3G conversions before on my 89 5.0 Vert and the connectors/wiring was a PITA) This way there are no connectors to worry with. I have pics and part numbers if anyone cares. One more thing to add the old 900 84-93 alts almost never go bad. If they do have a charging issue 99 x out of 100 its worn out brushes and they are availabe seperate for like $2.

[FomocoLoco72]

I forgot to add one small bit. I did have to add about 1 inch spacer (i used 10 washers .065 or 1.5 mm thick) behind the original Alt. spacer to properly align the it with the top bracket.

I just liked not having to rob a 10 year old (POS) connector off some old Taurus to make a 3G work like I did on my 89 5.0 Vert. You also do NOT have to worry about re-clocking the unit. the cables are at the bottom.

[Effie_70]

FomocoLoco72 I would like to learn more and see pics/specifics on this thanks!

[basketcase0302]

[67Doors]

Some great info in this post. Seems as if you can add a 3.8 Ford Windstar to the list. Was searching the local salvage yards and couldn't find any from a Taurus or Sabel but found one in a 95 Ford Windstar. I am getting ready to add an aftermarket AC kit to my 67 and figured it would be best to upgrade to a 3G alternator.

[mrollings53]

Get one from a Taurus with the 3.0L V6 OHV motor, Motorcraft PN: GL484RM. The mounting bolt spacing is 7" like on the OE alternator on our trucks. The 3G alt from the 3.8L motors has a 8.25" spacing; possibly requiring modification of the alternator bracket.

[67Doors]

Pretty sure I need the 8.25 because the motor and drive system is out of an 84-85 E-series.

[67Doors]

Get one from a Taurus with the 3.0L V6 OHV motor, Motorcraft PN: GL484RM. The mounting bolt spacing is 7" like on the OE alternator on our trucks. The 3G alt from the 3.8L motors has a 8.5" spacing; possibly requiring modification of the alternator bracket.

You are correct, I did need a 7". I was thinking the drive system was different but it's not. I was not able to find a GL484RM but I did find a GL477RM from a 97 Ford Mustang V6 that looks like it will do the trick.

[Calfdemon]

Just to note.. I did this 3G upgrade to CNM67's truck (390) and used a 3G with the 8.25 spacing. There was no modification needed and it bolted straight in.

I will be doing the 3G upgrade to my 460 when my crewcab is ready to be put back together and from everything I have read, the 8.25 is the way to go with that motor as well.

[67Doors]

Got mine in over the weekend. Pretty simple upgrade.

[motzingg]

well, i tried this today as i found a '90 t-bird in the yard with a brand-spankin-new alternator in it! I was super psyched but something about it didn't look right, couldn't put my finger on it.

long story short, got home and realized that it was a 2G... DAMN!

Anyhow, i've been doing research today into trying to figure out what various models had the 'good' 3-g, as in the 130 amp with the correct 12/5 bolt position for mounting.

Here's what i've come up with:

2G vs 3G: Pretty simple, 2g has external fan, 3g is internal. 2G has the plug, 3g has the stud. Easy, you gotta be a moron like me to screw it up.

The 130/95 amp thing is pretty straight forward, the 2 vs 4 hole thing is a dead giveaway, plus slightly larger case, but when your digging in the yard, the 2/4 hole thing is the easiest to spot.

The majority of the motors you see in the yard are either side mount or top mount. Just about every motor i looked at today was side mount or 'mod' motors, which don't work. You can see a good breakdown of the different cases on this website
http://www.rjminjectiontech.com/collections/alternators

You are looking for a 3.8 or 5.0 engine. 94 or later. I made the mistake of grabbing the '90 T-bird 3.8L which was 2G.
3.0:
Tarus, windstar, sable 94-99

3.8:
94-95 Tarus, Windstar, Sable

3.8/5.0
94-2000 Mustang, T-Bird Cougar

Now here's the weird part, for some reason the 'truck' 5 liters which are econoline, f-series, etc. are all side- mount. Should be a similar engine, but it is totally different.

The cool thing about the 3G's is that they are all modular it looks like, so if you did find a real crusty one that was a spread mount, and a real clean one that was side mount you could probably take the two and put them back together. If you go to a yard like i do, you could buy two, take the best parts out of both, and return the one full'a junk parts.


anyhow so thats my little bit of knowledge for right now. I'm going to try to get the alternators swapped out on friday and see what i can come up with.

This is another good option if you want to buy a new one. I really want every last bit of juice to run an RV/mobile workshop, and i'm pretty set on the junkyard thing, but for someone with a little extra money and just regular run of the mill electrical demands, this would totally be the way to go.
http://www.summitracing.com/parts/tff-7 ... /make/ford

[motzingg]

i'm also digging up info right now for the 200+ amp alternators. Some folks in the aftermarket are selling 200A 3g's which is sweet, but you gotta buy them new. From everything i can find, the 200A 3g was never sold as an OEM alternator by ford.

Still, they aren't that expensive and I'm thinking once I do the 130 Amp, if my demands exceed that, i'll spring for the 200A... now, whether or not a V-belt can drive it, not sure about that one. If it was on anything, i would bet it was on a police interceptor, which are plentiful in the yards as dead taxis, and they usually go in running/wrecked instead of blown up... so that is a good sign. Rock auto lists a special CVPI alt. that is 130 and they also list a Remy reman unit http://www.rockauto.com/catalog/moreinf ... cc=1108370 that is 165A for CVPI's... it looks like the same 'large case' 3G with 2 holes and top mounting for a 4.6 Mod motor, but thats about it.

once again, you'd have to do the buy two, switcharoo manuever with the CVPI alternator, but if it spent most of its life in a taxi it probably wasn't taxed much, running very low duty cycle most of the time, so the hard parts could have a lot of life left in them.

There are also 4, 5 and 6G alternators that go up to and beyond 200A for newer cars with more junk on them, but i can't find as much info in the aftermarket about them. Seems like that might be an easier one to find, and in good condition, in the yard.

The 'ambulance' alternators are awesome, 200+ amps, but the mounting for them is totally wacky. I bet they also have a much better duty cycle because they have huge fans, cases, and big heat sinks on the rectifiers... but once again, good luck finding that in the yard, and you'd be on your own for a bracket.

as for the v-belt:

130A x 12V= 1560W = 2.1hp x 1.25 efficiency factor= 2.625 Hp

If i remember correctly, a standard A style v-belt can handle about 5 hp so that should be fine. Getting up to 200A puts you up to 4 hp by that calculation, so that is really pushing the limit for the standard V-belt drive.



looks like i'm gonna go back to the yard and go back to cuttin' belts and spinnin' alternators...

[Dr Farnsworth]

After lot's of reading on this site (love fordification.com) and others, I decided to pull the trigger on a 3G alt upgrade. I am planning on installing an electric fan and I knew I would need the power the 3G puts out.

I am not going to bore you with a step by step on how I did the install. The main thing I wanted to do is let you know how I wired it and what 3G alt part number worked for my build.
My 69 f100 has a FE 360 and the alt mounts low on the right side.
I bought a rebuilt alt that was supposed to fit a MERCURY SABLE 3.0L(182) V6 1994-1999 and had these part interchange part numbers: F4DU-10300-DA, F4PU-10346-DA, F4PZ-10346-D.

As you can see in the pictures, it's almost an exact fit on the hole spacing!
The old two groove pulley fits the new alt but will rub the case unless you put a small washer behind the pulley to shim it out.



This picture is with it in the truck. Yea I know the wires are a mess. I wanted to make sure everything worked first before I worked on fixing the wires.


I traced the switched DC wire ("S" wire on the old voltage regulator, it would be the "I" wire if you don't have an ammeter gauge). I am pretty sure it's "904" in the wiring diagram.
The main power from the alt I sent through a 175 amp mega fuse and then to the starting solenoid.
Wire "38" coming from the old alt also splices with wire "37". It appears this is the main power to the truck. I wired it to the mega fuse opposite the alt.
Wire "655" and "654" appeared to be for the ammeter. I replaced the old crusty inline fuse holders with new blade 5 amp fuses. "654" I wired directly to the positive output on the alt, "655" I hooked directly to the positive terminal on the battery. I wanted the distance between the two as far as possible to help with the "shunt" that is needed for the gauge to work. And it does!

On the new alt I ran switched dc from wire "904" to the "I" terminal on the new alt. "S" goes to the stator on the alt. "A" I routed to the mega fuse.




I may have gotten something wrong, if I did please be gentle on me!

[BobbyFord]

I plan on doing this swap on my short bed 460. I just dropped an NOS ammeter off at the speedo shop to get converted to a volt meter, I'll just have to rewire the instrument cluster plug. I want to keep the gauge cluster looking stock but I want a functioning charge gauge.