• Hello Guest, welcome to the initial stages of our new platform!
    You can find some additional information about where we are in the process of migrating the board and setting up our new software here

    Thank you for being a part of our community!

GM Alternator Swap

shouldnt be a problem with a 240 install should it? I bought a reman 100 amp unit im tired of going through volvo units.

The voltage regulator on my old 100 amp volvo unit was toast, too late to fix it i already broke 3 blades trying to get the pulley off.

The Gm alt seems like a direct fit except for a few spots of grinding and a 4 prong terminal

The connections on the gm:

phase connection: this terminal is used to send a signal to a relay or frequency sensing tachometer. There may not be a wire leading to this terminal.

Indicator lamp: When used, this terminal is connected to the vehicles indicator lamp. A 300 to 500 ohm resistor is connected across the lamp to provide a "start charging" signal if the lamp burns out.

Ignition Terminal: When used, this terminal is connected to the vehicles ignition switch.

Sense battery voltage: When used, this terminal provides the alternator with a precise battery voltage reading.

what needs to be hooked up?

thanks
~Kyle
 
Last edited:
I've been having great success with the Ford 3G alternator, as found in the late '80s/early 90s 3.3 litre Sable/Taurus. 135 amps, internally regulated, 2 wire hookup, and there are plenty of v-belt pullies that work with it. Got one on my 244 and one on my 765, and we're putting one on Dale's 122.
 
Matt Dupuis said:
I've been having great success with the Ford 3G alternator, as found in the late '80s/early 90s 3.3 litre Sable/Taurus. 135 amps, internally regulated, 2 wire hookup, and there are plenty of v-belt pullies that work with it. Got one on my 244 and one on my 765, and we're putting one on Dale's 122.
Click to expand...

Got pics and notes on what needed to be done? I need more amps aswell.

Thanks
Renny
 
holtzboy said:
Renny, I am in the process of installing a 240 amp GM alternator i bought from a member on here awhile ago. Its different than the 3G one shown above but it might have some similar wiring to it. You can check my thread on it here:

http://forums.turbobricks.com/showthread.php?t=74477.

Also I asked about wiring on the 'other' Volvo forum and got some responses:

http://brickboard.com/RWD/index.htm?id=1079278

Hope this info helps some.
Click to expand...

Holy crap 240 amp, well you'll be ready for a monster stereo system. Lemme know how it goes.

I'd love to find a single wire high output alternator so that I can run highbeams, wipers, and stereo and still roll the windows up and down.

Thanks
Renny
 
I am confused: I have in my 94 Jetta a 90A Bosch Alternator. We tested it (good thing to be friends with the shop owner) with the engine running and we were getting 120A at 3500RPM. Food for thought.
 
if you ever buy an alternator new. it will come with a spec sheet on it. My 100 amp gm alt goes as high as 120 amp and as low as 95. average is 105amps

the amps increase as the rpms do,

on another note, the gm alternator wasn't too hard to install and it works great.
 
Alright now I guess I will need some assistance with the wiring as well. I thought I had it all figured out but I am getting crazy voltage dropping with my GM 240 amp alternator. The belt is nice and tight and I am not getting any squeeling. The alt is almost identical to the back of this one:

alt_diagram.jpg


This is how I wired it up, for the S Terminal, I just connected it to the alternator output stud, L terminal went to the small red wire for the dummy gauge light, and the IG Terminal went to the available pin 15 on my coil. With this setup the dash light comes on when the ignition is in the accessory position and when the car is started it turns off. Voltage starts out at 14.5v but then after 30 seconds or so it drops down to around 13.8 and hovers in the mid to high 13s. If I rev it up it will goto 14.5v again but then go right back down to the 13s. I still have the stock red power wire from the starter going to the alt + stud as well as a short 4 gauge wire going to the battery positive terminal. For the alternator ground wire, its a 4 gauge cable thats only 5" long and bolts to the fender where I sanded off the paint.

I have an 80 amp alternator in my 244DL with the same type of upgraded wiring and the voltage always stays at 14.4v and never drops below 14 unless I am blasting my stereo which even then will only go down to about 13.6v. So I am not sure if I screwed up the wiring to the three terminals on the back of the GM alternator or whats going on. I might throw the stock 55 amp on to see what kind of voltage readings it gets. Any hints or suggestions would be awesome! Thanks.

EDIT: Might make a big difference but the voltage regulator is internal right? If I am supposed to hook up an external one that'll help the voltage problems just a wee bit.
 
Last edited:
Have you tried turning things on to increase the load and see what the Alternator then does. The 120 amp in my suburban will sorta go into idle if the battery is full and their is no load on it. This may just be how the GM voltage regulator works.

I'm interested in doing this swap also just to get enough voltage to run everything and not have to worry.

Thanks
Renny
 
For what it's worth I've had my S80 fan in for a few days now with a stock 70 amp alt. At cold idle when the car gets up to ~160* and the fan turns on, there's only a slight stumble in the idle then it's fine. I can lower both power windows with the fan on, while driving, with the cd player going (basic unit, 2 speakers) with no ill effects. Although my problem is that my battery doesn't hold a base charge so when I shut the car off I usually have to jump it :rofl:. Probably not too good for the alt, but whatever.
 
It is kind of weird, on a cold startup of my car the voltage will stay at 14.5 volts until it gets warmed up then it will start to fluctuate. Without anything on the fluctuation will be from 14.0 - 14.5 and when I turn accessories on it will be from 13.7 +. This only happens at an idle and if I rev it up at all the voltage will goto 14.5 and stay there. I asked someone who did the swap and he said that he ran into the same problems so he got a smaller pulley for the alt so it would spin faster at idle and keep the voltage up. It is only a small annoyance because once I get going and am not idling it will be fine.
 
You must log in or register to reply here.
Back
Top