GM Alternator on a '78 FJ40

[toyotaboy92]

Ok I am sure this has been covered plenty. I read and read for a few hours on the FAQ on adding a Delco 12si to replace the stock alternator and external Voltage Regulator. I just want to make sure I am doing it right for my year of FJ.

After reading I have determined this is what I should do (I think..):

12SI, 94 amp, at 3:00 (AC-DELCO # 321-266, Lester #7294-3)
Tell the auto parts counter person that “The alternator is for a 1984 High performance Chevy Camaro, with 5.0L (305G) engine, 94amp alternator

or

12SI, 94 amp, at 9:00 (AC-DELCO # 321-269, Lester #7294-9)
Tell the auto parts counter person that “The alternator is for a 1985 Buick

Also it looks like I need to add this so the engine will shut off when I turn the key to OFF

diode pt# 1n5404 from radio shack

Also I would like to retain use of the Amp Meter on the dash but never found if that was possible or not.

If anyone has any input please share there seems like there were a ton of ways to do this mod and would like to hear what works the best.

Thanks, and sorry to bring up a dead horse but don't want to jack up my FJ.

Jeff

 

[crushr]

Your stock wiring and ammeter are only sufficient for the output of the stock alternator. if you replace your alternator with a higher output unit, you need to upgrade the charge wiring from the alternator to the battery accordingly, and replace or bypass the stock ammeter.

Many folks (including me) just get a "one wire" GM alternator, eliminate the ammeter altogether, and run a voltmeter instead.

 

[joeyg1973]

The amp meter is just never going to work with an upgraded alternator.

If you are going to go with a 12si for the cost you might as well go for the CS-144.

Whatever one you choose you will need to put in new wiring capable of handling the higher output. You will need the diode that you mentioned.

 

[toyotaboy92]

Ok sounds like the amp meter is toast. Got that. Any suggestions on size wire that should be installed to handle the upgraded alternator? Also anyone have some good pictures of their install. Thanks for the input so far.

 

[Trollhole]

How about a cs-130? Scroll down in the link.

https://forum.ih8mud.com/60-series-wagons/144065-delco-cs-144-alternator-installed-pics.html

 

[toyotaboy92]

Is the diode still needed back where the Voltage Regulator was for the CS130?

 

[bsevans]

This is my setup, a Mean Green 200 amp GM Delco. I bypassed the ammeter and ran new wire from the battery to the fuse panel and ignition switch. The wire from the alternator to the battery is either 2 or 4 gauge Vu-Tron UL Listed cable. It is the orange cable in the third photo. The first photo is the alternator with the GM replacement harness that uses Teflon insulation. The second photo shows the spacer required to keep the alternator in the correct position to align with the other pulleys. Notice that the dual pulley is meant to run the toyota belts.

 

[joeyg1973]

How about a cs-130? Scroll down in the link.

https://forum.ih8mud.com/60-series-wagons/144065-delco-cs-144-alternator-installed-pics.html

Same thing as the 12s, if you are going to spend the money for that, might as well get the higher amp cs-144. Whatever you choose you still need to do the same work.

 

[LAMBCRUSHER]

up to 50 amps= 8 gauge, 51-70 amps= 6 gauge, 71-90= 4 guage, 91-115amps=2 gauge. you could prolly get away w/ 4 gg. to 95 or so amps. When in doubt, go bigger- and only use automotive or welding cable: super fine stranded wire of copper. the stranded wire gives more surface area of coductor than the same diameter wire in a solid form. Voltage and current ride the surface of the conductors. I liked the set up by BS Evans. No mods to the factory bracket other than the spacer? Superclean!

 

[handcannon]

Is the diode still needed back where the Voltage Regulator was for the CS130?

I installed a CS130 a couple years ago. No diode, no problems, I like it.

Don

 

[Pin_Head]

I had a CS130 in a GMC suburban and the wire size was approximately 8ga. I didn't measure it, but it looked smaller than 6 ga and 8 ga would be the next smaller common size. It itsn't likely that you will be putting out a full load for an extended period of time, unless you have some high current accessories, like a 1000 watt sound system. Don't forget an appropriate size fusible link to protect the wiring and alternator if bad things happen, like a diode fails or someone connects the battery backwards.

 

[Trollhole]

Same thing as the 12s, if you are going to spend the money for that, might as well get the higher amp cs-144. Whatever you choose you still need to do the same work.

Not the same thing. Not if you want to do a whole lot of fabbing to your Alt bracket or add a ton of washers.

Just look what this guy did. What a hack job.

This is a CS-130. Any Alternator shop can build you one in any amp configuration and they can also make it one wire hookup.

It's for a 92 Eagle Premier or Dodge Monaco. I believe you could find one from 90-92 in these vehicles.

All you have to do to install it is grind a little off the top of the alt bracket.

 

[toyotaboy92]

Thanks Trollhole. looks like the cs130 is the way I want to go. I ended up picking up a 12s to see how it would fit and looks like it fits perfect between the bracket but the pully is too far back to be inline. Also the moron gave me the 74amp one instead of the 94. I am taking it back and going to have him get me one like yours. I don't feel like ordering special brackets and tons of washers. Did you run a diode inline from the key on yours?

Thanks for all the help everyone!

 

[Trollhole]

No diode that I know of. Just follow Cruiserbretts writeup in the tech links above on hooking it up. http://www.ih8mud.com/tech/cs130.php

 

[1978freebornred]

what would happen if the stock ammeter was used a fire?