Hi guys. First off, I have searched, and appreciate all of the information. I've come to the conclusion that I want to do my own rebuild, and with a high output kit. I just have a quick question- based on the below picture, can you tell me which alternator I have? I'm on alternatorparts.com and just simply don't know which one it is. I looked all over the case, but its pretty filthy, and the only marking I see says Delco.

 

if you get a parts # you can get the amperage, or you can go to the dealership and give them your VIN and they can tell you what it came w/ stock, it might be a good idea to get a 105amp alternator if your updating your engine and electrical system. most V8's came with the 105amp alternator.

 

Well, I bought an alternator and apparently it is the wrong one. Its way too small. I still can't find any markings on my alternator other than the manufacturer. But, based on the comparison, can anybody give me a clue as to which alternator I have?

The clean alternator is the one I bought today- it is made for a 1988 350 motor. The dirty alternator is mine, and its much bigger than the new one.

 

I'm debating on whether I should just buy the brackets for the smaller alternator and use them. I probably won't ever put huge audio in here, and 105 amps will probably suffice. The smaller alternator currently fits my brackets, but needs to be moved so far out that the belt can't reach it. So, I either need new brackets or a longer belt.

The smaller alternator has a 6 rib belt, though, and my crank only uses 5. Does this matter? Or will the belt just "ignore" the empty valley?

 

Your old alternator is a run of the mill 12si.

 

Thanks so much! Now, one more question- which year/engine combination did it come on? My car is an 88 with a 350, but that combination brings up the smaller alternator that I bought incorrectly.

I just want to know what to tell the autozone guy so that he can give me the right one.

Once again, thank you so much for the input.

 

Your newer one I think is a CS130. My 84 used the 12SI, but my 88 has the CS130. I'm not surewhat year it started to be used, I'd have to look it up. If I had to guess, it would probably be around 86 or 87 or so, whenever the belt arrangement changed.

Your engine has been swapped, so I wouldn't necessarily expect that the accessory arrangement would be the same as it would in a factory thirdgen.

 

Thanks very much for your assistance. I'll just get the autozone guy to grab a couple alternators from the shelf using the year ranges you specified. I really, really appreciate your help- I was starting to feel lost with all the different case types!

Update: You were right- it was off of an 86. Actually saved me 15 bucks too. Only $72 at autozone with the lifetime replacement warranty. Thanks man, I'm back on the road.

 

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The problem with old alternators is, the part # is stamped on THE CASE, which has ABSOLUTELY NOTHING WHATSOEVER to do with its relative output capacity compared to others of the same model.

The things that DO determine capacity are INSIDE the alt, and DON'T have a part # stamped on them. Those are, the stator winding, the rotor, and the regulator circuitry.

For the stator, you want one with good core steel (no idea how you can tell that, but they're NOT all the same), heavy-gauge wire in the windings, and good thick terminals on the ends. For the stator, you want one with, again, good core, and a large number of turns of relatively large wire. The regulator is impossible to tell much about from the outside. The car itself can help; the exciter wire should be connected to the alt through a relatively small value of resistor, but not so small that it's possible for the alt to supply enough power through it to keep the car running when you turn off the ignition, and the sense wire should be connected somewhere well downstream of the batt, at the central power distribution point if there is one.

The number stamped on the case is WORTHLESS. Rather like looking at the block stamping on a rebuilt motor and thinking that's going to tell ANYTHING about the motor's properties.

That Mechman looks alot like the truck KG3 alt for mid-2000s trucks with electric fan and all that kind of goodies.

 

The link I posted above handles the mechanical and electrical installation

 

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