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65?Amp to 30Amp Alternator Upgrade

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65?Amp to 130Amp Alternator Upgrade

I did this some time ago because my volt gauge shook around like Michael Jackson in the Thriller video when I turned up my stereo in my 90 Bronco. I took pics with my phone so quality is not that great on some pics, sorry. Anyways I did this swap for $35 bones for an alternator and about $15 for wire and eyelets. I got a used alternator off a '97 Cougar w/ 3.8l. For some reason these motors had a huge amp alternator, they have electric dashes and all that crap (I supose you could find the same alt on a lincoln continental).

Tools you will need:
  • 3/8" ratchet
  • 3/8" 13mm socket
  • 3/8" 15mm socket
  • 10mm wrench
  • 13mm wrench
  • 14mm wrench
  • small screwdriver
  • wirecutters
  • die-grinder w/ aluminum bit
  • wire crimpers
  • appropriate size drill bit and drill(for helicoil)

Additional stuff:
  • 3 feet 4gauge or larger wire w/ 1/4" and 5/16" ends
  • bolt and nut or helicoil
  • 14gauge 1/4" ring terminal

First disconnect your battery

Next remove the belt, I believe it's a 15mm on the tensioner pulley...but it's been a while.

Remove the top and bottom bolts holding the alternator to the bracket, I believe the bottom is 13mm the top is either 13 or 15mm.

Disconect the alternator and toss it.

Next step is to deloom the wires you just unhooked. (bad pic)

Oh look the reason why these alternators started fires (I'd assume anyway)

Disconnect the big green (fuseable link) wire from the solenoid 14mm nut. cut the yellow wire about 4 inches from the small connector. cut the white wire by the small connector. Discard the two black wires, whats left of the white wire, and big connector.

When you go to the yard to get an alternator ake sure they give you the clip. You need to remove the white pigtail (by unpinning it not cutting it) from the yard alternators connector.

Pull back the plug.

Remove the red clip.

Remove the pin from the connector by depressing the top of it (the metal part down inside) while in the connector and pull it out. You will now use the same techniques to reinstall it inplace of the white wire you cut on the trucks small connector. Don't forget to restuff the plug.

Here you can see the back of the new alternator with the broncos plug. It has the white wire from the junkyard plug installed in both plug and alternator. You can also see the green wire which runs to the instrument cluster(the only wire you didn't remove) and the yellow wire.

Now put a ring terminal on the end of the yellow wire, use a good terminal preferably with a shrink tube end. Put the eyelet over the post.

Here is the new alternator (top) It has an internal fan and a larger pulley. Originally, I put the smaller pulley on the donor alt. thinking that would be better. However, it was so small the belt squaked when I started it so I recently put the original (larger) pulley back on it. It is safe (by my calculations) to run the alternator w/ the smaller pulley as long as you don't rev the engine up past 4.5k or so. After that it exceeds the design of the alternator for rpms, ie greater than 6K.

Now you have a choice. The top of the new alternator is not threaded like the old one. You could put a bolt through it; but, I was going for an original look. I put a helicoil in mine. You will also have to notch the gusset on the alternator bracket about 3/8" or so for it to clear the larger case. Also depending on your application you may have to change the clock position. That's pretty simple just three bolts. Don't pull the case apart!, just rotate it and reinstall the bolts.

Now install an appropriate gauge wire to the terminal on the back and tighten down the nut. Mount alternator. Attach the other end of the wire to the solenoid terminal you removed the green wire from, reinstall nut. Mount alternator.

Here you can see I used a vaccum cap to gaurd the alternator terminal.

I should also tell you to put a fuse in the wire from the alternator to the solenoid, but I will also say I have not and haven't had any problems the year I've had it installed.
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