• Welcome to ClassicBroncos! - You are currently viewing the forums as a GUEST. To take advantage of all the site features, please take a moment to register. It's fast, simple and absolutely free. So please join our community today!
    If you have problems registering or can't log into your account, please contact Admin.

Learning about 3G alts

Apache Bronco

Jr. Member
Joined
Jun 14, 2012
Messages
70
Loc.
Roosevelt, AZ
Ok, I was thinking about replacing my orig. alt. with a higher amp with cool styling, and I learned about 1G, 2G, and 3G alts from recent posts.
Should I hunt one down from a wrecking yard (PHX), if so, which 94 up vehicles besides Mustangs,
Will my old v-pulley work, if not, which,
Wiring advice, will get the pigtail for it.
Plan on halogen headlight upgrades, winch, lights, ham radio, etc.
Thanks, Lisa
 

cali_zuk

Jr. Member
Joined
Dec 11, 2006
Messages
66
I used my stock v-belt pulley, and purchased the fused wiring harness from wildhorses. Night and day difference between the stock one and the 3g. You will also have to do something with your amp meter wiring. You should be able to find a write up in the tech section.
 
OP
OP
A

Apache Bronco

Jr. Member
Joined
Jun 14, 2012
Messages
70
Loc.
Roosevelt, AZ
Good news on the pulley. Is the fused wiring harness for the headlights, I didn't see any on the WH site for alts, but did read about Paul!
 

DirtDonk

Contributor
Bronco Guru
Joined
Nov 3, 2003
Messages
47,345
Hey Lisa, whatever you read it's not true!;)
Nice of Ford to keep the same basic bolting style and shaft diameter on so many alternators for us. The only thing I've seen happen on some pulley swaps is needing to use a small spacer behind the pulley or not. They come with many of the alternators, but you'll have to try your pulley first to make sure it sits on the shaft and does not rub the body of the alternator.

There is a downside to using a v-belt pulley though sometimes. Belt squeal.
Especially in the morning! Luckily you're area is dry enough that you might get less squeal, but it's likely still going to happen. I think there have only been a handful of members here with 3G's that did not get to experience the lovely dulcet tones of a slipping belt on a 3G!
That's why so many of us have gone with a serpentine drive system over the years.
But on a simple Bronco setup without a lot of other accessories another option is dual-groove pulleys. Or a larger diameter pulley too would help.

The Taurus is another common junkyard donor for both the smaller and larger case versions of the 3G. And either size fits the standard Bronco brackets usually. The exception is if your Bronco has the heavy cast steel bracket that originally housed the alternator and the air pump/thermactor setup. Those make the smaller 3G a better choice. Or better still (assuming no air pump) is using the standard triangle upper and curved lower brackets.
There are charts here on the forum in other threads that list the entire older vehicle donor list. Maybe google it using the "site: classicbroncos.com" criteria along with your search terms. Seems to be more robust than the search button here, but either might work for you.
Or, if we're lucky, someone will just post up the list again because they have it saved from previous discussions.

I think both the 95 and the 130 amp versions of the 3G are available in both size cases, but not 100% sure anymore.

The fused wiring harness that I think cali_zuk is referring to is this one: https://www.wildhorses4x4.com/product/Battery_Charge_Cable_AMG_fused/Bronco_Starters for protecting the main charging circuit.
The fuse blows if the alternator has an internal failure or something short-circuits the cable.

We do also have the fused relay harness for the headlights (https://www.wildhorses4x4.com/product/Night-Lighter-Headlight-Harness/Bronco_Wiring_Harness) since you mentioned it;D
It's not a requirement for protection (the stock headlight switch has it's own circuit-breaker protection) but it's virtually a necessity for getting brighter headlights with a stock wiring harness.
And often still a good thing after a full re-wire with a new harness even.

Hope that all helps.

Paul
 
OP
OP
A

Apache Bronco

Jr. Member
Joined
Jun 14, 2012
Messages
70
Loc.
Roosevelt, AZ
Thanks Paul, great help. I would like to go serp belt if I can afford it. My 68 is from Los Angeles so I have the air pump etc. Didn't know about sm/lg case alts. Good info! Hubby says ac delco website is good for alt info, will have to check it out. Going to a junkyard to get a late model fusebox, so I will probably be doing custom wiring for the alt and halogens.
 

Slednut10

Contributor
Guru? That's funny!
Joined
Sep 26, 2013
Messages
2,394
Here's an ebay link for a larger v-belt pulley that I used on mine.

https://www.ebay.com/itm/Single-Gro...e=STRK:MEBIDX:IT&_trksid=p2055119.m1438.l2649

And a partial list of 3g donors to look for in the boneyard


94-96 Mustang 3.8 V-6
94-95 Mustang 5.0
94-96 Thunderbird 3.8 V-6 (non SC)
95-96 Windstar 3.0 V-6 (most are 3.8's)
93-96 E/F series Trucks/Vans 4.9 L6*
96 Sable 3.0 V-6
94-96 Cougar 3.8 V-6

(1994-95) Ford Mustang 5.0L
(1994-00) Ford Mustang 3.8L
(1994-97) Ford Thunderbird, Mercury Cougar 3.8L
(1990-95) Ford Taurus, Mercury Sable 3.8L
(1993-99) Ford Taurus, Mercury Sable 3.0L
(1995-98) Ford Windstar 3.8L & 3.0L
(1991-94) Lincoln Continental 3.8L
(1992-97) Ford F Series Pickup
(1992-96) Ford E Series Van
 
OP
OP
A

Apache Bronco

Jr. Member
Joined
Jun 14, 2012
Messages
70
Loc.
Roosevelt, AZ
Ah Ha! The later v8 takes the side to side top mount, I need to look for v6 engines in the trucks. The alt for my husbands 99 f350 won't work.
 

Rustytruck

Bronco Guru
Joined
Feb 24, 2002
Messages
10,875
When swapping to my small case 3g alternator the stock Ford pulley needed a spacer behind the pulley and the alternator shaft so the pulley didn't rub the case. Then when the pulley was on there wasn't much thread for the nut.

I went searching for another pulley and found the GM pulley fits much better and left enough threads for the nut. I am using a 2 groove Delco alternator pulley.
 

DirtDonk

Contributor
Bronco Guru
Joined
Nov 3, 2003
Messages
47,345
Yes Apache, for our purposes we're talking about the "standard" mounting type alternators. Or whatever that style is called.
The "side mount" style that came on many vehicles starting in the mid-nineties obviously needs it's own specific brackets to work. The '97-'01 Explorer is a perfect example (like your husband's F350) where the alternator that is actually a 4G or higher vs the 3G, and will only fit with the Explorer or the F350 bracketry. It might look like your F350 version or those on Mustangs in '94/'95 too I think, but the bolt spacing is different for each.

But if you go off that list Slednut posted you should be good. I see the first listings are for Mustangs that I mentioned as having the side mount type. So maybe there were some changes in there, but I had a '95 Mustang with the 3.8 and it most definitely had the side mount type that would not have been compatible with our setups.

But it's all good. You'll know when you see one that works.

Paul
 

DirtDonk

Contributor
Bronco Guru
Joined
Nov 3, 2003
Messages
47,345
And if the AC Delco site is good for information, don't fall into the "you need a GM 1-wire alternator for your vehicle" hype. Everybody in the hot-rod world seems to think that it's the only way to go. Which it is most definitely not!

While I'm not completely for keeping everything Ford on our Broncos, I do prefer using Ford parts more often than not when it's an available option. In the case of the alternators though, it's not because I'm keeping Ford parts on my Ford, but more because the 3G alternators are some of the best out there! Very good output especially at lower speeds where it's needed.
Very stable and reliable and uses the same wiring colors and connections as Fords all over the place.

So whether a standard 3G or a 1-wire like we sell (just to further simplify the already fairly simple wiring), the 3G is a great option.

Paul
 
OP
OP
A

Apache Bronco

Jr. Member
Joined
Jun 14, 2012
Messages
70
Loc.
Roosevelt, AZ
I like the 2 groove v belt pylley/3g (3rd generation?) alt setup, tho as with all mods I will have to keep a list of mfgs/part numbers in case of replacement. Mods are a slippery slope...
 

RPM289

Sr. Member
Joined
Jan 4, 2008
Messages
835
Hey Lisa, whatever you read it's not true!;)
Nice of Ford to keep the same basic bolting style and shaft diameter on so many alternators for us. The only thing I've seen happen on some pulley swaps is needing to use a small spacer behind the pulley or not. They come with many of the alternators, but you'll have to try your pulley first to make sure it sits on the shaft and does not rub the body of the alternator.

There is a downside to using a v-belt pulley though sometimes. Belt squeal.
Especially in the morning! Luckily you're area is dry enough that you might get less squeal, but it's likely still going to happen. I think there have only been a handful of members here with 3G's that did not get to experience the lovely dulcet tones of a slipping belt on a 3G!
That's why so many of us have gone with a serpentine drive system over the years.
But on a simple Bronco setup without a lot of other accessories another option is dual-groove pulleys. Or a larger diameter pulley too would help.

The Taurus is another common junkyard donor for both the smaller and larger case versions of the 3G. And either size fits the standard Bronco brackets usually. The exception is if your Bronco has the heavy cast steel bracket that originally housed the alternator and the air pump/thermactor setup. Those make the smaller 3G a better choice. Or better still (assuming no air pump) is using the standard triangle upper and curved lower brackets.
There are charts here on the forum in other threads that list the entire older vehicle donor list. Maybe google it using the "site: classicbroncos.com" criteria along with your search terms. Seems to be more robust than the search button here, but either might work for you.
Or, if we're lucky, someone will just post up the list again because they have it saved from previous discussions.

I think both the 95 and the 130 amp versions of the 3G are available in both size cases, but not 100% sure anymore.

The fused wiring harness that I think cali_zuk is referring to is this one: https://www.wildhorses4x4.com/product/Battery_Charge_Cable_AMG_fused/Bronco_Starters for protecting the main charging circuit.
The fuse blows if the alternator has an internal failure or something short-circuits the cable.

We do also have the fused relay harness for the headlights (https://www.wildhorses4x4.com/product/Night-Lighter-Headlight-Harness/Bronco_Wiring_Harness) since you mentioned it;D
It's not a requirement for protection (the stock headlight switch has it's own circuit-breaker protection) but it's virtually a necessity for getting brighter headlights with a stock wiring harness.
And often still a good thing after a full re-wire with a new harness even.


Hope that all helps.

Paul

Will this harness work on a 66 Mustang? :) :) Thanks!!!
 

DirtDonk

Contributor
Bronco Guru
Joined
Nov 3, 2003
Messages
47,345
Yep. Same connectors at the headlamps, probably the same wire colors as well. And probably just about the right length of wire.
Connect it the same way according to the instructions.

Your battery is on the passenger side as well, correct? Either way it will work, but you could reverse the order or installation if your battery is on the other side from a Bronco. Same thing, only different.

Paul
 

DirtDonk

Contributor
Bronco Guru
Joined
Nov 3, 2003
Messages
47,345
Should not effect the headlight harness in any way I wouldn't think. So you'd be ok connecting it now and then changing your battery layout later.
Most use the original battery as the main battery still, and the secondary battery as their backup. So all your stuff connected to the old battery is still legit and stays pretty much as-is unless the battery cable routing changes things.

In the old days a simple on-off relay (factory) or a rotary switch, or an "isolator" aftermarket were the main ways of doing a dual setup. Nowadays I prefer the really BIG relay setup with a 3-position switch on the dash.
Here's the Painless version: https://www.wildhorses4x4.com/product/Painless_Standard_250A_Dual_Battery_Kit/Bronco_Batteries

In one position it's charging only the main battery. Another position it's charging both batteries. The third position is the cool one though, as you can self-jump start yourself from the (hopefully still charged) auxiliary battery.
Saved my bacon a few times when my battery wasn't as healthy as it should have been and my Koolatron refrigerator drained it before morning.
Flip of the switch and away I went!

Paul
 
Top