Alternator Dummy Here!

[ol Curt]

After asking a few questions on another post about what alternator to look for in a 3 wire system, I went out and looked at mine. Heck, it is a 3 wire! But....I think it is wired into the voltage regulator. Is it possible that mine has an internal regulator, but would run ok with it hooked to the external one? I haven't really driven the truck much, but did notice the generator light on last time I started and moved it.

What next?

[Corts60]

I've never heard of any alternator having an external regulator? I'm also not very versed with them though. Maybe just un-hook the external regulator and wire it up regularly and then see what kind of voltage you are getting at the battery....or maybe take the alternator down to the parts store and have them test the output?

[fixit-p]

I think what you want is to convert from an external regulated alt to an internal regulated alt both are 3 wire not counting the ground wire if intact. The Delco 12SI alternator (there are other choices) is perfect for this upgrade its bolt in with two jumpers at the regulator plug to bypass the old regulator and change the alt plug and your good to go. Here is some good reading on the 12SI and other auto elec. tech. http://www.madelectrical.com/electri...elcoremy.shtml

[markeb01]

It's most likely you have a stock 1966 externally regulated alternator. It would require some research to determine the changeover year, but I believe most or all GM alternators were externally regulated until around 1972. Once they developed the internally regulated models the old electro-mechanical external regulators became obsolete. I believe the internal regulator is solid state, while the external models had points that burned, wore out and required adjustment is something went wrong.

[stellar]

Pull the plug out of the alt. If the connections on the plug look like this ll it is an external reg type alt. If the plug looks like this _ _ it is an internal type alt.

[ol Curt]

Thanks, I'll take a look at that tomorrow. Would there be a great advantage of going from three wire external to internal other than not having to use the regulator on the front of the truck?

[Eagar1]

I believe the internal reg style pump more amps, are more reliable, and simplify the wiring. The old regulators are not as efficient, and can act sporadically depending on temperature, humidity, vibration, etc.

[stellar]

If you don't need extra amps there isn't much advantage. After all the truck has worked well for quite a few years like it is. However if you need to change both the alt and reg, the internal will cost less and be easier to find. The internal aslo puts out a little better at low RPM. You can also buy a stock alt internal in the same size case in amp ratings of 37 42 55 63 66 78 94.

[MacAttack]

Originally Posted by Eagar1

I believe the internal reg style pump more amps, are more reliable, and simplify the wiring. The old regulators are not as efficient, and can act sporadically depending on temperature, humidity, vibration, etc.

All true - went old school on my C10: Regretting it presently - won't do it again, way too complicated (at least for me) and just like fishing rigs - the more connections you have, the more things can fail.

Mac.