Help identify Alternator

[BlackMamba]

Hi all, I need help identifying this alternator. Came in my 86GT and need to replace it. I have another 86GT and the top connector is different. Was going to get one from a different 86 and it still doesn't match my connector. Anyone using this alternator ? Is this even a mustang alternator?
I'm wondering if my plugs have been changed.
Any help will be appreciated.

Thanks guys.

[Haystack]

That's an older style, ive seen them on full sized ltd's. Pretty sure those require external regulators and there should be some sort of regulator box inline with the alt wiring.

With a 3g, the only thing you need to keep is the dash light wire.

[dagenham]

Is there a protective cover or something missing? I've never seen a connection like that on a Ford before.

[BlackMamba]

That's an older style, ive seen them on full sized ltd's. Pretty sure those require external regulators and there should be some sort of regulator box inline with the alt wiring.

With a 3g, the only thing you need to keep is the dash light wire.

Any idea on what year LTDs? So far this car has gone through 2 new batteries and it's on its 3rd. Warranty will expire soon so I'm trying to figure out if I should use it or not? It's getting rebuilt as we speak and I'll be picking it up soon.

Is there a protective cover or something missing? I've never seen a connection like that on a Ford before.

Not sure if there's something missing as this is how I bought the car.

[dagenham]

Are you sure the alternator is the problem?? What happens to the batteries to cause them to go bad?

[JACook]

That alternator is a 2G that's been modified to use a screw-terminal output connection, in place of the factory push-on
style. Not sure what kinda diode bridge was used to make it that way. The 2G alternators have a reputation for burning
up the output connections, primarily because of improper service procedures. New connector pigtails are available to put
it back the way Ford made it, but you'd also have to put the original Ford-style diode bridge back in it.

The main thing with the 2G output terminals is, they must be clean and tight, and you must apply fresh dielectric grease
on the terminals any time they are disconnected.

[BlackMamba]

Are you sure the alternator is the problem?? What happens to the batteries to cause them to go bad?

No im not 100% sure the alternator is the problem. I figured since it's been over 5 years since it's been replaced, I would start there. The battery will usually last about a year and crank slowly then won't charge back up. So far Autozone has replaced them free of charge but I need to fix this issue. At night time the lights dim when I come to a stop and get brighter when I accelerate. Swapped it yesterday and the cars runs better. I still have to go for a night drive to see if the lights still dim or if that issue is resolved.

That alternator is a 2G that's been modified to use a screw-terminal output connections, in place of the factory push-on
style. Not sure kinda diode bridge was used to make it that way. The 2G alternators have a reputation for burning
up the output connections, primarily because of improper service procedures. New connector pigtails are available to put
it back the way Ford made it, but you'd also have to put the original Ford-style diode bridge back in it.

The main thing with the 2G output terminals is, they must be clean and tight, and you must apply fresh dielectric grease
on the terminals any time they are disconnected.

Thanks for all the info JACook. Which ones are the output terminals again?
The shop who rebuilt the starter said they can put it back to the OEM style bridge. Is that something you'd recommend?

[dagenham]

It depends. You can put it back to original if you are restoring the car. But if you aren't worried about originality then you might want to think about upgrading to a 3G conversion. Your lights will be brighter and they get dimmer and brighter as you are driving and you will have more amps to better supply any extra electrical add ons. I.E. Stereos, other lighting, etc.

[JACook]

Having the output connections put back to the way Ford made them would give you easier options if you need
to replace an alternator, vs the one-off kit you have now. The same could be said for a proper 3G conversion,
though the devil is in the details.

As for the lights dimming at idle, that problem is more pronounced if you have underdrive pulleys, and/or the
pulley on the alternator you have is larger diameter than the one that should be there. Even a 3G alternator will
let the lights dim a bit if it's not turned fast enough at idle.

[dagenham]

Having the output connections put back to the way Ford made them would give you easier options if you need
to replace an alternator, vs the one-off kit you have now. The same could be said for a proper 3G conversion,
though the devil is in the details.

As for the lights dimming at idle, that problem is more pronounced if you have underdrive pulleys, and/or the
pulley on the alternator you have is larger diameter than the one that should be there. Even a 3G alternator will
let the lights dim a bit if it's not turned fast enough at idle.

The lights shouldn't dim down with a 3G conversion because those alternators go directly to the battery.

[JACook]

I'm not sure how to take that ^^^ comment. Are you really suggesting the alternator output wire should connect
directly to the positive battery terminal? Hopefully not.

The reason you upgrade the output wire on a 3G swap is simply because the the stock output wiring was only sized
to carry the amount of current that the stock alternator can deliver. It is perfectly fine with a stock alternator, but
it is not adequately sized to carry the amount of current that the 3G can deliver.

The reason I brought up pulley size is because, while it's hard to tell for sure from an internet photo, the pulley on
the OP's alternator looks to be a larger diameter than the stock 1-7/8" pulley. Because of the small diameter of the
alternator pulley, seemingly small changes can have a disproportionately large effect.

My own '93 LX 5.0 vert never had a problem with the stock 2G alternator, until I put underdrive pulleys on it. But all
it took to solve the problem was to put the smaller stock alternator pulley back on. I left the underdrive crank pulley
in place.

Every alternator needs a certain amount of rotational speed to keep up with it's nominal 14.5V output. Because
incandescent lights are very sensitive to voltage, they dim noticeably with even small voltage changes. That doesn't
necessarily mean the battery is being discharged. As long as the system stays above about 12.5V, you'll be fine.

A 3G alternator does tend to have more output at lower speeds, but if you slow one down enough with your pulley
combination, your lights will dim at idle. Conversely, you can also speed up a 1G or 2G alternator with your pulley
combination, to eliminate the dimming. Up to a point.

The main reason to swap to a 3G is when you've added electrical loads beyond what Ford originally spec'd the stock
alternator to handle. If you haven't done that, or don't plan to do that, there's nothing wrong with keeping a stock
alternator. These cars managed just fine for many years, before the 3G came into being.

[stangPlus2Birds]

The lights shouldn't dim down with a 3G conversion because those alternators go directly to the battery.

Where the alternator's output goes doesn't make any difference at all.

Get a DVM.

The battery voltage is always lower with the engine off. The alternator always makes the car's voltage higher when the engine is running.

Having a Giga-watt alternator means nothing. You care about how much current can the alternator supply when the pulley is driven at "speed x".

Many of the 2G high-current alternators have very low/poor/sucky current output at low speeds. The same is true for 3G alternators, especially those that have "upgraded" current output.

The above is why *I* went with a PA-Performance high output single-wire alternator. The voltage sense-wire is the better/correct way to do things. But, with my '86, and the tons of BS/conflicting/incorrect info on the interweb, I said "screw this" and went with the single-wire alternator.

Also, it's always a good idea to put a fuse between the alternator and the battery. These alternators can have a failure mode where they short the output to ground. If that wire is connected directly to the battery - "something" is going to give. The wire will burn up and/or the battery will explode. Imho, either is a good way to ruin a car and your day/life.

I used the PA-Performance wiring and fuse kit. I also had to go to a starter solenoid that had longer terminals, so that I could connect the beefy power-cable to the stud.



Modified the bracket with the cut-out relief needed for the 3G. Fwiw, a right angle grinder makes quick work of that mod.







The starter solenoid with the longer studs:




The installed alternator.





You can see the mega-fuse holder right above where the battery sits. Yes, it is tight.
Note that my ABS unit is where the coil and starter solenoid were originally located.

[BlackMamba]

It depends. You can put it back to original if you are restoring the car. But if you aren't worried about originality then you might want to think about upgrading to a 3G conversion. Your lights will be brighter and they get dimmer and brighter as you are driving and you will have more amps to better supply any extra electrical add ons. I.E. Stereos, other lighting, etc.

I've been wanting to do a 3g conversion but just not on this car. This one is my 86 Saleen so I'm trying to restore it back to factory as much as I can.

Having the output connections put back to the way Ford made them would give you easier options if you need
to replace an alternator, vs the one-off kit you have now. The same could be said for a proper 3G conversion,
though the devil is in the details.

As for the lights dimming at idle, that problem is more pronounced if you have underdrive pulleys, and/or the
pulley on the alternator you have is larger diameter than the one that should be there. Even a 3G alternator will
let the lights dim a bit if it's not turned fast enough at idle.

True, I'm going to take it back to the shop and have them put the original output connection to make it look factory.
I do have FMS pulleys but not on the alternator. I'll have to measure the pulley that is on the alternator and measure a stock 1g alternator to compare.
So let me get this straight, if the pulley on the alternator is smaller, does that mean the lights will dim more at idle?
Would it be a bad idea if I swap it out for a FMS pulley?

[Haystack]

Smaller is faster. Usually under drive pulleys slow the crank and speed up the alt.

My local junkyard had a sale on alternators for $8.99. Just for fun I checked how many tauri they had, and it was over 40. One of the best mods I ever made and only took about an hour being really careful and making it look good.

[Walking-Tall]

Yep, a smaller diameter alternator pulley will speed the alternator up, so your lights should not dim more at idle, but less or not at all. No pulleys have any affect on crank speed. "Under-drive" pulleys slow down everything else, with a smaller diameter crank pulley, and/or bigger diameter accessory pulleys.

Example, from a home-brewed under-drive change (a pulley off of the discarded AIR pump, onto the crank snout) I made years ago with my Marquis (upper, factory pulleys - lower, smaller crank pulley):



Take a look at those RPMs. It's a good thing alternators have some needle bearings in them! LOL!