GM alternators

[Crosley.In.AZ]

Internal regulated alts..... big case....... little case.

Is it the large case with 6 vent holes on the back side?

S series?

[1FATGMC]

Internal regulated alts..... big case....... little case.

Is it the large case with 6 vent holes on the back side?

S series?

I guess I'm too dense to figure out the question for sure.  I do know you can change the 3-wire ones to 1-wire internal by just swaping some internal parts.

I have that information ( HERE  ).

I now carry those parts with me as when my one-wire went south once on a trip I found out the parts houses don't carry one-wires in stock.  So with a couple parts you can buy a new 3-wire and convert it to a 1-wire very easily.

This probably didn't answer the question you were asking, but it gives me a chance to say I like your new ride.

c ya, Sum

[Crosley.In.AZ]

I found out that the unit I have is a 12si.  same mounts as a 10si, larger case, suposed to be more durable, better low RPM voltage.

i found a one wire 12si unit on the net for 120 bux , rated at 105 amps.

I am not sure if the same parts on Sum's site will bolt into the case to provide a 1 wire operation.  


Seems like you can jump a wire from the batt terminal to 1 of the pair of connectors.  then run a wire from a charge  indicator light to the other terminal?

[Dave]

I found out that the unit I have is a 12si.  same mounts as a 10si, larger case, suposed to be more durable, better low RPM voltage.

i found a one wire 12si unit on the net for 120 bux , rated at 105 amps.

I am not sure if the same parts on Sum's site will bolt into the case to provide a 1 wire operation.  


Seems like you can jump a wire from the batt terminal to 1 of the pair of connectors.  then run a wire from a charge  indicator light to the other terminal?

Ive got a one wire that says it can also be wired up as the 3 wire configuration. Im gonna try it and heres the reason why. Starting cold is fine goes on high idle from the choke and the alt charges real good. Hot engine it sucks. Start it and unless you remember to rev the engine fairly high it doesnt charge at and idle. I forgot to rev er up a few times and was cruzin at low speed and the radio started acting funky and stuff cause i had less that 12 volts at the battery... Im still not sold on the one wire configuration. Do it right and you only need one other small wire to energize  the field of the alt so it charges. I already got one wire going to the starter battery terminal and an electric choke wire and a temp sender wire so what the heck whats one more wire..
Dave

[enjenjo]

Seems like you can jump a wire from the batt terminal to 1 of the pair of connectors. then run a wire from a charge indicator light to the other terminal?

Yes that will work tony. the two wire on the small terminals are typically, brown and red. Red goes to the big terminal, and brown goes to the charge light, then the accessory side of the ignition.

[Crosley.In.AZ]

Seems like you can jump a wire from the batt terminal to 1 of the pair of connectors. then run a wire from a charge indicator light to the other terminal?

Yes that will work tony. the two wire on the small terminals are typically, brown and red. Red goes to the big terminal, and brown goes to the charge light, then the accessory side of the ignition.

problem is I do not have a connector for the alt  to guide me

[tomslik]

#2 and the post can be jumped.
#1 needs a powered idiot light ran to it.

1+2 should be marked on the case

[Ed ke6bnl]

#2 and the post can be jumped.
#1 needs a powered idiot light ran to it.

1+2 should be marked on the case

I have herd people run a resister accross the bulb, so if the bulb fails the alt will still charge. I had a bulb fail and no charging occurs. Ed ke6bnl

[Dave]

Seems like you can jump a wire from the batt terminal to 1 of the pair of connectors. then run a wire from a charge indicator light to the other terminal?

Yes that will work tony. the two wire on the small terminals are typically, brown and red. Red goes to the big terminal, and brown goes to the charge light, then the accessory side of the ignition.

problem is I do not have a connector for the alt  to guide me

Tony the parts stores sell the plug for the alt. Get one dont just put spade connectors on it and wire it up. I had the connectors break of a 100 amp alt and I need a new one fast so i bought a 60 amp and use the 100 for a core :cry:  The plug gives the wires needed support.
Dave

[Crosley.In.AZ]

I solved the problem, ordered a 1 wire alt from summit.


thanks

[PeterR]

I have herd people run a resister accross the bulb, so if the bulb fails the alt will still charge. I had a bulb fail and no charging occurs.

I always did that on marine motors.  Having the electric supply of a boat relying totally upon a indicator bulb just does not seem a good idea to me.

By soldering the resistor into the circuit you also eliminate potential problems caused by corrosion of the bulb contacts.

[model a vette]

The 12si was GM's first attempt at a high amp alt. It came on some high end Pontiacs and Buicks, I think with the first "heated" back glass. They were about 100 amps. They were fairly rare and the core charge was excessive when they were new (late 70's).