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GM alternator conversion


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21 replies to this topic

#1 subiemech85

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Posted 08 December 2003 - 12:11 AM

How do the wires connect to change subaru alt. wiring to GM alt. wiring wanting to run 100+ amp GM 82 Cadillac alt

#2 LostWater

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Posted 08 December 2003 - 09:02 AM

I have pictures and a write up of this conversion. My hatch is not running, so I haven't felt comfortable posting yet.

Here is what I found:

Take a look at the subie wiring connector. It looks like a "T", with one spade perpendicular to the other spade. The GM connector has a clicker on it. Lay them down side by side. The clicker on the GM connector should face up. The straight up and down spade from the subie connector is the same as the left side of the GM connector.

I just ran a jumper wire with male spade on one end and a female spade on the other to connect the subie connector to the GM alt. This way one doesn't have to cut the subie connector off.

Press me for pictures and I may send them.

BTW, I also ordered the conversion from JCTwitney and made mine 120 amp. I had ****vance test it when I was finished and it passed with flying colours.

Mark

#3 northguy

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Posted 08 December 2003 - 09:44 AM

WOW! Talk about the potential for toasting thewiring harness. One crossed wire and POOF. Good luck with that one. I guess I'm too timid to play with that one.

#4 carfreak85

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Posted 08 December 2003 - 12:40 PM

I wnt some pictures and a good write up here and in the USRM!!!

#5 Nomad

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Posted 08 December 2003 - 04:19 PM

Oh, OH, pick me! pick me! Over here! I know this one!!! <waving arm frantically...> :D

Okay, first off, I don't have pics. Second, I had access to a shop at the time: read, welder and a whole bunch of used alts lying around, for pulleys...

The alt is a CS model from an 86 fwd bonneville... It was serpentine, and I used a pulley from an old ford one...think it was from a rustang 2.3. Having figured out the wiring makes it easy to install the 140 amper I got from a Caddy... POWER!:headbang: :slobber:

Anyhow, I read a bunch of stuff on CS alts, and how its really easy to install them on just about anything, you just need the right bracket configuration. I fabbed my own.

as for the wiring, I made an adapter, so no cutting was done on the Sube's own harness.

Only two wires are actually necessary. One is the output, the other IIRC, is to supply the field voltage or something like that. In fact, the alt I used and the orig Sube alt worked the same way, just had difft connectors...

I'm gonna go refresh my memory and look under my hood...theres a link I have somewhere on GM alts that'll explain a bunch.

I figure once you understand how things work, you can make it work on anything... doesn't really matter who made it...

This mod is worth it!

Good luck

#6 archemitis

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Posted 08 December 2003 - 04:24 PM

i guess if your runing a giant stereo, or a welder, otherwise why?
an alternator that big must use about as much hp as an ac compressor.

#7 Rooinater

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Posted 08 December 2003 - 04:36 PM

i want to cause i'm going to be running a welder, winch, kc lights, dual battery's and a few other mods that use more amps.

#8 Nomad

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Posted 08 December 2003 - 04:53 PM

Originally posted by archemitis
i guess if your runing a giant stereo, or a welder, otherwise why?
an alternator that big must use about as much hp as an ac compressor.



Yes to all of the above!!:D :grin:

As for the hp use, i don't feel much difference... I suppose if I was dragging it, I MIGHT gain about 1/100 of a second off that awesome 18 second quarter mile time:lol:

And anyway, my a/c compressor is on duty now as an onboard air compressor, so I don't really use it that often. It kind of balances out...Besides, i need something to run those lights and charge the dual batteries...nevermind the winch i'll get soon.

For the Love of Subie!

#9 Rooinater

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Posted 08 December 2003 - 05:10 PM

need diagrams, cause i got to rewire the alt anyways. do to it's externally regulated and i want an internally regulated

#10 carfreak85

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Posted 09 December 2003 - 03:21 PM

need more! pics maybe?

#11 LostWater

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Posted 09 December 2003 - 03:24 PM

Hopefully I will get home early enough to take some pics.

I am slow sometimes, sorry. No excuses

#12 subiemech85

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Posted 09 December 2003 - 11:45 PM

need pics and write-up
bought correct plug for gm alt
will run 200 wats of accessory lights

#13 GeneralDisorder

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Posted 10 December 2003 - 06:25 PM

Totally - just a pic of the wiring and the mount would be good enough for me. I can replicate it if I have an idea on the wireing.

Doesn't seem that it would be too hard, as long as the alt is internally regulated like my 85 is.

GD

#14 LostWater

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Posted 11 December 2003 - 04:03 PM

First, the pics:

Posted Image

Posted Image

Posted Image

Posted Image

Here are a few details now:

Get two pieces of flat steel, say 4" long. Drill two holes in each at the EXACT same spot.

Get two pieces of 5/16 all thread, say 6" long

get eight nuts to fit said all thread (one to set each end, other used as a locker)

get a poopload of washers

get a belt that is 2.5 cm longer than original (ask me for part number later)

get some tube spacers for all thread of various lengths. Got mine from Slowes, can be had anywhere.

Take out old alt

take 1 piece of all thread and lock steel plate with one hole on each end after putting through orig. mountining hole for alt.

Take other all thread and push through ear of GM alt, shim with tube spacers and washers until right dimension and then put through the other hole on the steel plates that are already mounted.

Put belt over the pully and start wiggling to mount

Put fixing bolt in other end of GM alt and you tighten the crap out of it.

Take two pieces of wire 3" long each.

Crimp male spade on one end, crimp female spade on other.

I went to ****vance with both alts, compared plugs with their wiring colours, and this next graphic is what I came up with.

Posted Image
this is looking the back of the connector, just switch around if using just spades to alt. then a-b for each. (I will put just spades into the back of the alt)

Just hook the spade wires just built lining up A-A and B-B(or switched according to how you are wiring, see above). You probably as want the insulate the spades that go into the GM alt so they don't touch.

As always, your results may vary, and you are responsible for your own actions and verifying these details in your own application.

Does anyone want me to post pics and details of me rebuilding the GM alt with the JC Twintney 120 amp kit? (otherwise, this switch only gives you 10 more amps than stock).

MD

#15 Meeky Moose

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Posted 11 December 2003 - 04:08 PM

how much is a poopload?


just kidding.. very nice writeup... since it looks liek i'll be keeping the hatch, when the 2 stock alternators, and 2 xt6 alternators i have burnup, i'll have to do this conversion.. heh.. by then i should have some wicked lights on the top..

#16 Nomad

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Posted 11 December 2003 - 04:13 PM

Great job!

is that a 70-75 amper in there?

Your install looks a lot simpler than mine. I kept the A/C compressor, so I could use it for onboard air.

Wiring is almost exactly the same as mine... I kepth the alt end stock GM and found a Subaru connector to mate with the car harness. Joined 'em up and off I went. Coming up on 2 years, no probs at all.

Man, I REALLY need a digital cam...

Later

#17 Rooinater

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Posted 11 December 2003 - 04:20 PM

ok need to break it down really barney style. cause i under stand but a the same time don't have enpugh info. what's the size on the spacers" bolt's length. the 4inch steel plate is that full length used on the right side of the alt. (driver's right). a few other questions i'll have to ask to claify directions.

#18 LostWater

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Posted 11 December 2003 - 04:27 PM

And better details. I figured this could e an experiment for someone, but hey, I figured it out, I am sure it could save someone the hassle.

I believe the steel bar is 1" wide x 4" long. You will have to drill the holes to your specs.

There is a bar on each side of the mountings, with all thread connecting each, one thread through the mount on the engine, the other spaced out with tubes and washers in the ear of the alt until tight.

My compressor is still there, just not hooked up, I haven't decide wether I am going to fix the air, or turn it into an onboard air compressor.

That alt is a full 105 amps by the Jc Twitney rebuild kit. Twitney alt kit

MD

#19 Snowman

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Posted 04 February 2004 - 02:34 AM

What GM vehicle did you get the alt from? (Sorry if this was mentioned already, I couldn't find it.)

#20 subiemech85

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Posted 04 February 2004 - 10:40 AM

1971 - 1985 GMC (All Models) (exc. orginial 80- or 100-amp.) 105-amp Alternator Conversion Kit Kit 71ZX0646U $34.99

Delco alternators, used by GM and others, including massey Freguson, Allis, Deere, INT, start looking for what you want, basically all the same base unit

#21 Nug

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Posted 04 February 2004 - 11:14 AM

I think GM alts belong on everything, because they are so cheap, and they work pretty well, and they last a fairly long time. That, plus a lifetime warranty, and you'll never need to buy another.

I have one on my Jag in place of the smog pump. The Lucas is still on there, spinning, doing nothing, with the terminals burned off.

#22 Nug

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Posted 04 February 2004 - 11:25 AM

Posted Image

Just hook it up like this. Loop the one wire over to the B+ terminal, and the other goes to the light on the dash. Run a big (at least 10 gauge) diameter cable from the B+ terminal on the alt to the positive battery post, and you are done.

In this case, the purple wire goes to the battery, and the white one goes to the dash indicator. The red is the "tickler" wire, that needs to see what the battery voltage is in order to put out the correct voltage.




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