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Need to know Alternator Amperage rating!!!!

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Old 09-20-2000, 02:01 PM
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Need to know Alternator Amperage rating!!!!

Need to know... ASAP... its an 86, 2.8... I need to get a new alternator... dunno what amp I should get. I have AC.. if that matters...
Old 09-20-2000, 02:05 PM
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Usually cast into the alternator, somewhere. like "95A" for 95 amps... Whole bunch of other numbers, usually, too
Old 09-20-2000, 02:10 PM
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Car: 1986 Firebird
Engine: 2.8 V6
Transmission: 700R4
105 amp.. should be written on the case somewhere.

I have Pep Boys' lifetime warrantee replacement alternator. It cost me alot, but I've been able to bring it back 3 times within 6 years (bearings always overheat) and haven't had a problem with customer service.

-Tom P (Hot rodded 1986 Firebird 2.8l) from http://www.f-body.net/mailbag/3rd/3rd_mailbag.html message boards
Old 09-20-2000, 02:12 PM
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Tom... it says 97A on the case...is 97 Amps the right alternator?!?
Old 09-20-2000, 02:31 PM
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Car: 1986 Firebird
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Not sure dude, I coulda sworn mine was 105 amp. See what the parts store guy will give ya! Chances are if the outside looks the same then you've gotten the right one. There were some 67 amp alternators used, but they were much smaller in appearance.

-Tom P (Hot rodded 1986 Firebird 2.8l) from http://www.f-body.net/mailbag/3rd/3rd_mailbag.html message boards
Old 09-20-2000, 04:01 PM
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I've posted this several times, here goes again...

Go to a rebuilder before you plunk down any extra coins for a "high output" alternator, and watch the process they actually use to deliver their product.

They do not rebuild individual alternators. They get in cores by the pallet; they tear them all down, put the case fronts in one basket, the rears in another, the stators in another, the armatures in another, etc. They send each of the parts through its various cleanup and renewal stages. Then they reach into the barrel of fronts and pull one out, the barrel of rears, and pull one of those out; the same from the barrel of armatures; etc.

Now look at the alternator. The amp rating is stamped on the cse front. This part is an aluminum casting with no electrical function whatsoever. The parts that actually determine an alternator's maximum possible output, the armature and stator, were irrevocably separated from each other and from the case piece with the rating stamped on it at tear-down, and unless somebody specifically goes through the mass of parts and hand-selects them (builds one for himself or his friend not for going in a box), they are virtually certain never to be mated again.

Therefore, when you buy a rebuilt alternator, abot 99.999% of the time you're getting a totally random average selection of all the cores the rebuilder had on hand at the time.

So just go to the store and buy an alternator. If you don't like it, take it back. Keep doing it until you get one you like. Don't waste your money on the "rating" of a rebuilt alternator, it's completely meaningless.

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"So many Mustangs, so little time..."
Old 09-20-2000, 07:23 PM
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I used to work at an auto parts store, and what RB83L69 just told you is the absolute truth! That is why I always (or whenever possible) rebuild my own alt.s. Th rebuild kit usually cost $10.99 and it takes about 10 minutes (for me) to rebuild it. You can also scavange other alt's inerds (of similar design) to increase your alts output.

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George P. Lara
1994 Z28 LT1 T56
1984 Z28 High Output
Member: SCCA, SCFB, SC3GFB
Old 09-20-2000, 07:42 PM
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George,

Wow! Are you gettin' REAMED! The last repair kit I bought was only $9.95! (LOL). The last time I can recall having purchased a complete rebuilt alternator was when I needed a unit for a spare engine (no core). Other than that, I'm with you. Over 90% of the time the bearing noise can be repaired with a 6203ZZ bearing and over 90% of electrical failures can be repaired with a new set of brushes. I don't know if I've ever had a diode fail on one of my cars, and I had one regulator crap out about twenty years ago when the solid state regulators were still in their infancy. Beyond that, a thorough cleaning and a few buck worth of parts usually does the trick. And unless you live next to a parts store, it probably takes longer to fly for a replacement than to split and repair one of your own. Good call, George!

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Vader
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Old 09-21-2000, 07:23 AM
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Car: Transformed 86 Coupe
Engine: 400 sbc
Transmission: 700R4
As another option, take your alt to a local repair/rebuild shop. I may be lucky where I live, but there is a local shop that I can take alternators and starters to and they will completely rebuild them while you wait and watch! When they finish they load test the units and then hand it back to you! They add about $10 to the price of the kit and about $15 labor and you know you have a working unit that fits your vehicle when you leave.
I've watched them do a few and I will probably do my own next time based on the education I've received.
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