Tag 3G alternator

I have the power. Hello, all right folks, enough of that cheesy nonsense. Ed here, welcome back to Bullnose Garage. Today we’re talking alternators, specifically swapping out the stock 1G alternator for a 3G. As a bonus, I pulled a 3G alternator from my 351 Windsor donor vehicle, and I’ll be using that as a visual aid today.

If you’ve had your truck for a while, especially if you’ve added accessories like lights, new headlights, a better stereo, or maybe an electric fan, you’ve probably noticed that the 1G can struggle to keep up. This is where the 3G comes in. It’s got more power, better reliability, and fewer headaches. So let’s dive into why you’d want to make the switch and how to get it done.

So why do we want to ditch the 1G? Well, the stock 1G alternators from these 1980 to ’86 trucks were fine for their time, but they’ve got a bit of a reputation for being underpowered. They typically put out around 65 amps. It’s okay for a truck back in the ’80s mostly, but once you start adding aftermarket accessories like extra lighting or modern electronics, the 1G just can’t keep up. And then there’s the wiring. The 1G alternators have external regulators and use fusible links, which aren’t the most robust system. The connectors can overheat and melt, and nobody wants that under the hood. It’s like running a garden hose when you really need a fire hose.

Enter the 3G alternator. This upgrade for the mid-’90s is substantial. The 3G alternator is internally regulated, so it ditches that problematic external regulator and fusible link setup. The big deal though is the output. It’s much higher, anywhere from 90 to 130 amps depending on the model. That’s a big leap over the 1G’s 65 amps. What’s great about the 3G is it’s not just more power; it’s more stable power. You’ll get better voltage regulation, which means your truck’s electrical system is happier, especially at idle. With the 1G, your lights might dim or your stereo might cut out when you’re idling at a stoplight. The 3G helps prevent that. And if you’re running a winch or big off-road lights, it’s pretty much a must-have upgrade.

So right here I’ve got the 3G alternator that I pulled for my 351 Windsor donor vehicle. Let’s take a closer look. One thing you notice right away is this connector here. This is the voltage regulator. Unlike the 1G, which had an external regulator mounted on the fender, the 3G has it built right in. Another thing to note is the size. This one here is a 90 AMP version, which is just slightly larger than the 1G but should still fit in the same bracket with no major modifications. If the mounting points are correct, however, this one won’t work directly for a bullnose swap because the mounting ears aren’t correct. This one has three mounting points. What you need is a version with two mounting ears directly offset at the 12:00 and 6:00 positions. This is a side mount alternator, and you’re looking for a pivot mount alternator.

So how do I know this one’s 90 amps? Well, the 90 AMP models like the one I’m holding here have four vent holes in the rib sections on the front. If you’re looking for the higher output 130 amp version, those typically have two vent holes and are physically larger. That means the mounting holes in the 130 amp model are spaced further apart. So depending on your bracket setup, you may need to make adjustments for a proper fit. Also, keep in mind if you’re running a single V belt system, the 130 amp version might not work out. A single V belt can only handle about 100 amps before it starts to slip. So if you want to run the 130 amp alternator, you’ll need to upgrade to either a serpentine belt setup or a dual V belt system to handle that extra resistance.

Speaking of that, if your bullnose is running a V-belt setup like mine, you’ll also need to swap the pulley from the 1G onto the 3G. If the 3G has a serpentine pulley like this one, it’s pretty straightforward. Just remove the nut that holds the pulley onto the 1G, slide the V-belt pulley off, and do the same on the 3G to remove it. If it has a serpentine pulley, you’ll probably need a shim to move the pulley out just a bit so the belt doesn’t rub on the case, but those are pretty inexpensive. You can then pop the V-belt pulley onto the 3G alternator and tighten it down. That way everything stays compatible with your existing belt system.

And lastly, the output terminals. This heavy-duty charge stud here is where your main power connects. If you’re upgrading to a 3G, you want to run a heavier gauge wire from here to your battery or solenoid to handle the higher output. Now the good news is that even with all that that I just said, the swap isn’t too complicated. But like any job, you want to have the right parts and prep work done first. You’ll need the alternator itself, like the one I just showed you, but with the right mounting setup. The 3G alternators we’re looking for came off a bunch of Ford vehicles from the mid-’90s. To help you out, I put together a list of vehicles you can source a 3G alternator from, which I’ll throw up on the screen right now. Take a look at these vehicles. You’re looking at anything from the 1994 to ’95 Mustang, which had a 130 amp alternator, to vehicles like the Ford Taurus, Thunderbird, and even E-Series Vans. Other options include the Lincoln Continental and Mercury Cougar. You can pick these up at junkyards, and they’ll bolt right up to your bullnose with a little bit of wiring work.

Now, like I mentioned before, if you’re running a V-belt in your truck, you’ll also need to make sure you swap the pulleys. Get that done before you start the actual swap. You don’t want to find out that you forgot when you’re trying to wrap a V-belt around a serpentine pulley. That’s no fun. Now, if you’re not interested in sourcing a 3G alternator from a junkyard, there are plenty of aftermarket options available. Companies like PA Performance and Tough Stuff offer brand new 3G alternators that are designed specifically for older Ford trucks, including bullnoses. These aftermarket models often come with higher output ratings too, sometimes over 200 amps, and they’re built to handle modern accessories. And what’s great about going aftermarket is that many of these kits include the upgraded wiring, a pretty install V-belt pulley if you need it, and even instructions on how to make the swap as easy as possible. Now, they do cost a bit more than a junkyard pull, but it’s a solid option if you want peace of mind with new parts and you don’t want the hassle of digging through salvage.

All right, so you’ve got your parts. Time to get the old 1G out of there. First, disconnect the battery. That’s always the first step when you’re working on anything electrical. Then remove the old alternator. There’s usually a couple of bolts holding it to the bracket, and you’ll need to disconnect the wiring harness. Now, I’m not going to get into how to physically remove the alternator in this video. It’s fairly simple, just a couple of bolts, and there are several videos out there that will show you exactly how. It can be a bit of a pain to get down there with a socket, but just keep at it, and you’ll get there eventually.

Once the old alternator is out, bolt the 3G into place. It should fit right into the existing bracket with minimal fuss so long as you have the right model. If it’s a little tight, some folks have had to grind or modify the bracket slightly, but usually it’s nothing major. Now for the wiring, like I mentioned, the 3G has built-in regulation, so you won’t need the external voltage regulator anymore. Ditch that thing. The external regulator is typically mounted on the passenger side fender inside the engine bay. It’s a small rectangular box with a wiring harness plugged into it. You’ll wire up the new alternator using the 3G harness, so make sure you grab that from your donor if you go that route. If you’re making your own harness, the main thing to get is the power wire from the alternator to the battery or starter solenoid and the smaller wires for the ignition and dash warning light. This is also where you upgrade the charging wire. Go ahead and run that new 4 gauge wire from the alternator to your solenoid or battery, depending on your setup. Put a mega fuse in line to keep everything safe in case of a short.

Once it’s all wired up, double-check your connections. Make sure everything’s tight and secure. Then reconnect your battery, fire up the truck, and check the voltage at the battery with a multimeter. You should see somewhere around 14 volts, give or take. If it’s good, you’re in business. Take a spin around the block, turn on your headlights, crank up the stereo, maybe even turn on any accessories you got, and you’ll notice everything runs smoother, especially when you’re idling. And just like that, you’ve upgraded your charging system to handle pretty much anything you can throw at it. That is until you run your huge set of off-road KC lights while you’re cranking ACDC at your 2500 watt stereo.

So there you have it, the 3G alternator swap. It’s one of those upgrades that makes a world of difference in how your truck runs, especially if you’ve got a lot of electrical demands. More power, better reliability, and less chance of ending up on the side of the road with a melted connector. If you’re thinking about tackling this job, go for it. It’s a solid weekend project that’ll pay off every time you turn the key. Guys, if you learned something today, if you enjoy the content, give me a like, give me a subscribe. I really appreciate that. I’m not trying to beg, but it really does help me out. If you have any questions, comments, concerns, gripes, internet ramblings, stick them below. Thanks again for watching, guys, and we will see you next time.