I just got in the mail the 55-amp Delco-Remy GM alternator I bought off ebay on Monday. The problem I'm having is that I'm PRETTY sure it ISN'T the kind with an internal voltage regulator, but I can't figure it out for certain, I've been websearching for the last hour and still haven't found anything conclusive. Some things lead me to believe it does have an internal voltage regulator, but I just don't know. And if it doesn't, I need to know what kind to get. I'd probably know for sure by now, but I can't read the stampings on the case at all, they're too rough (not stamped well enough). All I can make out is "12V NEG" and I already knew that. I THINK it's a 10D or 10DN type based on what I've read so far. So, I'm gonna describe it since I couldn't find any pics of the back of this type online. When it's held upright, meaning the words on the back are in the proper horizontal position, the two-pronged male connector (labelled on either side "R" and "F") is right at 12 o'clock. In the middle of the back there are two expansion plugs, one big in the exact middle and one smaller, whereas most of the pics I found online of Delco alternators just had one big expansion plug in the exact middle. While I'm asking questions, I've got another one. This is for a dual-voltage system I'm setting up in my car. Keeping the original 6 volt generator system and just using the 12 volt for starting and maybe some accessories later on. I need to convert the existing system from positive to negative ground. I think all I have to do is switch the battery cable clamps from one battery terminal to the other, and reverse the connections on the back of the ammeter. Is that correct? Hell, any extra info on this setup that can be provided would be welcome
Really can't tell without a pic, but it SOUNDS like you're describing an older, externally regulated Delco alternator. Internally regulated offerings have one stud on the back where the thick wire goes, and an opening on top for a two-slot plug. The plug will have a red wire for the exciter, which is run to a keyed 12v ignition source, and a white wire which goes to your "charge" or "alternator" light on the dash (optional). If you have "R" and "F" designations on your alternator, I seem to recall that those go to Regulator and Field, respectively...but I convert everything to internally regulated using stock GM parts, so I don't remember too much about the externally regulated jobs!
I always just bought a complete alternator...normally giving up any old externally regulated ones as a core! I don't know if you can convert them or not, but a rebuilt GM standard internally regulated alternator shouldn't cost ya more than $40 as an average...maybe less! (I take 'em off donor vehicles or cars that my buddy's are gonna junk...rarely HAVE to buy 'em!)
Machinos, yes you can buy the conversion over the counter. I know the AutoZone in my area carries them. Although, internally regulated alternators in my areas are NOT $40 more like $55-$60 The conversion is just a simple trick by removing the rear casing on the alteror. Couple of bucks and you are good. Just make sure your coil is matched to the alternator's internal resistor or you could have problems.
Ok, I'm sure now it's a 10DN, I found an old article on hotrod.com that shows it. Apparently they were used on GM vehicles from '64-'69, so I should be able to just yank a voltage regulator from one of those.
the plug for internally regulated looks like (--) the plug for externally regulated looks like (||) (looks like you already have that one figured out)
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