whats my alt again

[flexmerc]

What type of Alternator do I have?

 

[gnpenning]

From that angle hard to tell for sure. Looks like a Delco 10 si

 

[904Bronco]

Looks to me like a GM alt... As stated above^^^

 

[gnpenning]

Should have asked if you are having issues.

If so, they are the easiest alternator to test and rebuild.

 

[flexmerc]

Nonissues, I want to know how much amperage it can support for additional electrical items...winch, lights etc

 

[flexmerc]

Sometimes when I'm cruising at 2000 plus RPMs (60-70) my charging system is barely at 12.8-12.5; My gut says it shocks be higher.
But no issues, at this time.

 

[gnpenning]

The ear that the upper adjustment bolt goes through is stamped with the factory amp rating. I said it that way since many have been rebuilt with stator and rotor swaps that would change output.

If you had a carbon pile load tester you could check output or if a local parts house does, most check for free.

How are you testing voltage?

 

[flexmerc]

I was testing voltage with my multimeter and verify with my sniper handheld screen

 

[DirtDonk]

Sometimes when I'm cruising at 2000 plus RPMs (60-70) my charging system is barely at 12.8-12.5; My gut says it shocks be higher.
But no issues, at this time.

You are definitely having issues. It should almost never be below 13 1/2 V when running. Typically on our older non-computer control vehicles it’s closer to 14 1/2.
So your gut feeling is correct.
However, it may have nothing to do with the original amp rating of the alternator, as much as it might have to do with a failing alternator.
Or a loose or deteriorating wire or connection.

 

[gnpenning]

It should be a little higher. Do you have clean and tight connections at all points. Sorry I have to ask.

This is basically a single wire alternator and you need to rev it up a bit to get it charging.

I've never noticed them to put out the same voltage I see people here quote. Somewhere around 13v is what I commonly see. Others may have a different experience.

The white plug is connected to the voltage regulator. On the backside you should see the tips of 3 screws showing. These mount the regulator to the case. On the bottom close to the bearing there is a D shaped hole. If you put a Allen wrench, screwdriver, piece of wire etc in the whole and touch the side of the case. This will ground the voltage regulator and give full output. You are only going in about 3/8s of a inch. Measure this voltage and report back. You should hear the alternator kick in.

You can also put a piece of metal on the back of the alternator with the engine running just above idle and the magnetic field of a charging alternator will pull it in.

 

[flexmerc]

Roger that, will do

 

[flexmerc]

So update on this old post; alternator is bad and needs replacement.
I am completing my engine swap, and I finally pulled the Alternators, picture below. I identified it as a Delco Remy 12 Si.

I want to swap in a 3G, but I figure it would cost more than just replacing the Delco Remy, but what model is? there are not any identify model numbers.

 

[DirtDonk]

Can’t help yet, until I get over to one of my books.
But are you in an urban area that still has an alternator rebuilder locally? Or “auto electric“ shop as they are usually known?
They could probably rebuild it and convert it to any output that you desire, for maybe just a little more than a bulk china rebuilt type. But with a higher likelihood to have better results.
They could also tell you exactly what it was originally.

I know things have changed a lot, but we never had a bad result from a local rebuilder in the past.

 

[DirtDonk]

Funny thing, but I’d love to just say that they are all the same.
Get a 12SI from a 79 Camaro, and it’s probably exactly the same model as came out of an 89 pickup. Except for amp ratings of course.
But I don’t know that.
Potential clocking changes are always a possibility, but with only one connection total on the back (BAT stud for the output), they may not even have had to alter that for different vehicles.

Are you ordering online, or do you have a local store that you could go take it down with you to and compare to what they’ve got on the shelf?

 

[flexmerc]

I can and will compare it an auto parts store, thats a good idea.

I do like the alternator builder idea too, id definitely like to have a higher output because of my planned upgrades.

 

[DirtDonk]

Sounds good.
And just like Ford alternators, only even more so, the AC Delco alternators can be built to anywhere from 60A to probably 200A without going to a different case.
I tend to favor middle of the road stuff myself, in the 100 to 140 amp range.

Honestly, I still prefer the Ford alternator design because it is actually NOT a 1-wire alternator. Still has the battery sensing and switched exciter wire. This is to keep you from having to rev up the engine to start the charging.
It’s not a huge deal, and certainly not a dealbreaker. But it’s just one of those things I happen to prefer.

 

[ntsqd]

As I recall there were 10Si's, 12Si's, and 17Si's. The 10's and 12's are nearly the same size if not exactly the same size while the 17 is a LOT larger. There's less support for the 17's, but box-stock they had higher outputs than either the 10 or the 12.
Even with a legacy install I'm not sure that I'd use any of them as the design is now pretty old. Talk to your local alternator shop though, because they are who are likely going to support you going forward. Run with whatever they suggest. It is what I do. When I was considering an Si conversion they put me in a CS to use instead. Wiring is a little different, mounting wasn't (as far as I know).

 

[flexmerc]

As I recall there were 10Si's, 12Si's, and 17Si's. The 10's and 12's are nearly the same size if not exactly the same size while the 17 is a LOT larger. There's less support for the 17's, but box-stock they had higher outputs than either the 10 or the 12.
Even with a legacy install I'm not sure that I'd use any of them as the design is now pretty old. Talk to your local alternator shop though, because they are who are likely going to support you going forward. Run with whatever they suggest. It is what I do. When I was considering an Si conversion they put me in a CS to use instead. Wiring is a little different, mounting wasn't (as far as I know).

What's the support for SI? Would your guys recommendation be to go to 3G?

Some additional details:
302
P.O. Centech wiring harness, with SI alt so the amp meter still works
I am currently running holley sniper 1 w/duraspark dizzy, kincer fuel tank with in tank pump

 

[DirtDonk]

I wouldn’t do a 3G, or even an updated SI, for anyone retaining the original wiring harness and an ammeter.
But you did say Centech, so that means, that as long as it remains in top shape, you can use up to a 95 amp 3G, or an AC Delco up to 90-100amp. No more than that.
If you really want to go with a high-powered, modern alternator, you’d have to bypass the ammeter, use a larger gauge charge cable directly to the battery, and monitor the system with a voltmeter instead.

I would think support for the SI is fine. Aftermarket companies still make them brand new, unless that’s recently changed. I guess you can do the research on that.
I certainly haven’t kept up on such things. But since you can still buy replacement generators for 70 year-old vehicles, and replacement alternators for 60 year-old vehicles, I don’t see why you couldn’t buy parts, pieces and entire units for 50-year-old vehicles.

 

[DirtDonk]

Has the vehicle run well with the Sniper 1 up to this point?
When did the alternator stop working, under what conditions, and was anything damaged?