How-To: Upgrading 89-93 MTX alternator to 94-95 MTX alternator

[ManySHOs]

Jon,

The 3G alternators on rjm are probably Mustang or T Bird only. It's been awhile since I've been on that site. I bought my 3G SHO alternator used (remember it needs to be from a 94-95 mtx). You may luck out and find someone parting out a 94 or 95 mtx. Snag the front engine mount bracket, alternator bracket, associated bolts and the alternator + pulley.

On my 93, I simply removed the old connector and soldered and heat shrunk the new one on. Green to green, yellow to yellow. I did not loop anything back to the B+ terminal (alternator out).

I ran new 2 gauge cable from the alternator, to the starter and replaced any old battery cables with 2 gauge. (I had previously installed my battery in the trunk using 2 gauge wire.) I needed to make a Y cable which I did using crimpable lugs from waytek wire. I also installed a fuse at the alternator as well. All of my connections were crimped, soldered and heat shrunk. I think that I bought almost everything from waytek wire to complete this project. I can try to take some pictures and/or clarify anything that's not making sense.

Oh - yes, I believe that you can simply mimic the gen2 starter setup and ditch the fender solenoid if you have a gen2 starter. I think that Kevin (NJSHO) did this on his gen1. You might want to PM him.

Ian

 

[jonheese]

Awesome, thanks, Ian.

Pictures would be great, if it's not too much trouble.

Regards,
Jon Heese

 

[jonheese]

I'm having issues making the alternator bolt up to my bracket because a piece of the the 3.2 head (from a 3.2 swap) is getting in the way (and yes, I did grind away the chunk of the head specified in the SHOtimes article).

However, I decided to post this in a separate thread, instead of cluttering up the how-to thread:

http://www.shoforum.com/showthread.php?t=107022

Please post all replies about my situation there. Thanks.

 

[jonheese]

Just to add a little info to this how-to thread, here's a shot of the '89-'93 motor mount bracket and the '94/'95 motor mount bracket:

The older unit is on the left and the newer on the right.

 

[ManySHOs]

Are you using the 94-95 mtx motor mount bracket? The 89-93 bracket won't work.

The bracket that Kirk sent you should (if I recall correctly) bolt to the AC compressor after the compressor is bolted to that motor mount bracket. (actually, you'd bolt the compressor in using the bottom two bolts, then run the top bolts through Kirk's bracket and the AC compressor). It's been a long time but that's how I remember it.

Ian

 

[jonheese]

Okay, I've got the engine in the car and I'm finally starting to wire this guy up...

On my 93, I simply removed the old connector and soldered and heat shrunk the new one on. Green to green, yellow to yellow. I did not loop anything back to the B+ terminal (alternator out).

Okay, sounds nice and simple. I'm with you so far.

I ran new 2 gauge cable from the alternator, to the starter and replaced any old battery cables with 2 gauge. (I had previously installed my battery in the trunk using 2 gauge wire.)

Okay, makes perfect sense to me. Got it.

I needed to make a Y cable which I did using crimpable lugs from waytek wire.

Whoa, wait a minute, you lost me there... What was the y-cable for? What color, where did it go, and why?

I also installed a fuse at the alternator as well.

At the alternator where? I assume the B+ post... That goes to the starter solenoid, right? Is that the "charge wire" (asking to clarify terminology)?

Also, I'm not 100% sure about the entire wiring scheme for the 94/95MTX system, and the EVTM for my '90 just confused me more (and George had modified the system a bit (2nd battery-- deep cycle-- in the trunk with a battery isolator wired up between the two) so I can't really use the former setup as reference either). So let me tell you the way I think it's all hooked up, and I'd appreciate it if you can correct any mistakes:

- The battery neg terminal connects to the chassis ground via the battery cable. This wire is left untouched in this upgrade.
- The battery pos terminal goes to the starter solenoid on the starter (since I'm using a Gen2 starter setup). This would normally not be affected by this mod, except that I'm doing a Gen2 starter upgrade at the same time.
- Also coming off the starter solenoid, on the same post as the pos battery cable, is a cable that goes up the the big B+ post on the alternator.
- The yellow wire from the new alternator harness goes to the yellow wire on the old alternator harness (where does this ultimately go?).
- The green/red wire from the new alternator harness goes to the green/red wire on the old alternator harness (this is for the alt light on the dash).
- The white/black wire loops from one alt connector to the other, as is obvious. This wire doesn't appear to exist in the old wiring diagram, was it internal?

So assuming all of that above is correct and complete (I'm sure it's not, especially since I don't have any y-cables in my description), how does power get to the rest of the car? Do I need to run a power wire from the starter back up to where the original starter relay was on the fender? Should this be a big (eg. 2ga) wire? I'm guessing yes.

Thanks for any help you (anyone) can provide on this.

 

[jonheese]

Bump.... Can anyone help?

 

[element913]

When I did this mod I made somewhat of a junction where the old starter solenoid was, since pretty much all the electrical stuff converged at the starter solenoid on the fender.

It seems in your setup you are connecting the alternator to the starter, at some point the battery must be connected to the starter as that's where all the juice comes from (when starting).

I recommend having a thick wire (2/4ga) going from the battery to the starter (as its considerable amperage to start the car), you can probably get away with a 10/8ga wire from the starter to the junction (on the fender), provided you run a 2/4ga from the alternator to the starter (which becomes a second junction).

Starter: B+ from alt, B+ from battery, 10/8 ga to fender junction.
Fender Junction: 10/8 ga from starter, yellow regulator wire, green fusible link (for interior stuff IIRC). There may be other wires at that junction, it's been a long time since I did the mod.

In my case it was just easier to run a wire from the alt to the junction and then from the junction back to the starter. It also provided a stable area for a fuse/CB.

 

[jonheese]

Okay, thanks for that info.

Any idea what the Y-cable Ian was talking about is for?

 

[moobypets]

ok i may need some help on this cuz my 90 alternator is acting up again

i have a 94 3.8 and i have a brand new alternator on it with 170 amp and i would love to use it on my sho and stop having prb

is there a way to use the 94 3.8 alternator and put it on my 3.0 sho

i have the original conector since i have the complete 3.8 engine but would this fit

or i need a mtx aternator bracket from a 94 95 absolutely

 

[jonheese]

The 3.8 alternator and the associated bracketry is different from all of the SHO-model units, so I don't think this thread will really help you any.

 

[moobypets]

crappppppppppp cuz it look exactly the same as the 94 95 sho

 

[jonheese]

Well, I know that the part number for the '94 3.8 alternator is a different part number from the '94-'95 SHO unit, so it should be different, or it might be the same...

All told, it might be the same, but you're not likely to encounter someone who's an expert in the 3.8 stuff here, since this is the SHOforum... You might have better luck on the TCCA forums.

Good luck!

 

[moobypets]

lol yeah im on tcca but nobody would be dumb enough to use a 3.8 alternator lol

 

[moobypets]

so i just figured out something the 3 g alternator just have different casing so i can go and have it replaced internally with my 3.8 inside im just wondering about the 7 000 k rpm lol

and since my car has external regulator on the alternator and it only has 2 conector it supposed to be and easy connection