Alternator amps

[DFlynn]

So, after checking a bunch of connections and testing the battery and alternator which both tested good. still had problem. I really felt it was an intermittent problem with alternator and it just wasn't happening when they tested it. Luckily, I convinced the staff at O'reilly's and they warrantied it and gave me a new one. Problem solved. Thanks to all for replies.

So, after checking a bunch of connections and testing the battery and alternator which both tested good. still had problem. I really felt it was an intermittent problem with alternator and it just wasn't happening when they tested it. Luckily, I convinced the staff at O'reilly's and they warrantied it and gave me a new one. Problem solved. Thanks to all for replies.

Could you tell the part# of alternator you got from Oriely's?

 

[devildogcummins]

bump, have the same alternator and cant find one local

 

[edgephoto]

My '87 GMC has the same alternator. The model is a 12Si. They came in a few amp ratings but all were physically the same size. So go with a 94amp unit. I recommend Bosch AL559N. It is new and carries a lifetime warranty. You will have to swap the pulley.

CS130 alternators are great but they are not a bolt in replacement. You would need to modify your brackets. Personally I don't think it is worth it.

Lastly, if your truck has a smaller capacity alternator you will need to replace the wire going to the stud on the back of the alternator to handle the extra current.

 

[Ricko1966]

^^^ if shopping your local auto parts store. Make model etc. 1984 camaro,z28 ,airconditioned ,94 amps. It is the simplest swap ever. Using these application criteria,you shouldn't even need to swap pulleys.

 

[edgephoto]

As Rick says if you know the right combo you can get what you want. The issue with parts stores now-a-days is they rely solely on the computer. So when you come at them with something not stock their heads explode. If you have an old school store around they typically can deal with requests like "I need an alternator, 12Si with 6 rib serpentine belt pulley". Otherwise you need to come prepared.

I like Bosch for starters and alternators. They are new, not repainted, have lifetime warranty. When I had my shop we tried various brands until we settled on Bosch. Other brands might be a bit cheaper but if a customer broke down due to a failed alternator or starter the warranty was the least of the issue. The tow and labor to replace were not covered and the damage to your reputation is not worth the chance to make an extra few bucks.

Before we started buying rebuilds we used to use a rebuilder up the street from our shop. They did awesome work, price was good and they were fast. I had a Jaguar with a Lucas alternator and had them rebuild it. It failed twice inside of 6 months. The last time the owner said "I am getting out and will only be selling rebuilt and new units. I can't get decent parts anymore. The Chinese stuff is killing my reputation." He gave me my money back. That was a Lucas alternator. I bought a GM 12si alternator to put in its place. I got the best price from Auto Zone. That unit failed twice in a year. I am a cheap skate so I tried to save money. Got sick of replacing alternators. The original lasted 25 years. Put a Bosch in and it was there 5 or 6 years later after I sold the car.

 

[75gmck25]

The CS130 and equivalent are excellent, but are a slightly different form-factor and wiring than the old 10si. Not a big job to adapt, but some folks don’t want to modify anything electric.

My choice - The 94 Amp 12si is a drop-in replacement for the old 10si, and the 12si is sold with either a serpentine belt pulley or a V-belt pulley. I have a v-belt 12si on my ‘75 350 and I could take a look again at the Lester number to verify the model. You apparently need the same clocking, but with a serpentine pulley.

I also recommend you upsize the charge wire from the alternator BAT to the starter lug if it’s still the stock 10 gauge wire. I pulled the charge wire off a newer 90’s truck in the junkyard, so I got the larger wiring and it already has the fusible link. I also ran it directly over to the battery positive, so it’s easier to ensure it’s always tight. Easier than crawling under the truck to check that the power connections are tight.

FYI - Alternators use the Lester number for cross-reference to determine the clocking (where the power terminals are relative to the mounting bolts) and the pulley type. However, you can usually disassemble it and reclock to a different orientation if you need to. If you want a full tutorial on alternators, go to the madelectical.com web site

 

[Ricko1966]

As Rick says if you know the right combo you can get what you want. The issue with parts stores now-a-days is they rely solely on the computer. So when you come at them with something not stock their heads explode. If you have an old school store around they typically can deal with requests like "I need an alternator, 12Si with 6 rib serpentine belt pulley". Otherwise you need to come prepared.

I like Bosch for starters and alternators. They are new, not repainted, have lifetime warranty. When I had my shop we tried various brands until we settled on Bosch. Other brands might be a bit cheaper but if a customer broke down due to a failed alternator or starter the warranty was the least of the issue. The tow and labor to replace were not covered and the damage to your reputation is not worth the chance to make an extra few bucks.

Before we started buying rebuilds we used to use a rebuilder up the street from our shop. They did awesome work, price was good and they were fast. I had a Jaguar with a Lucas alternator and had them rebuild it. It failed twice inside of 6 months. The last time the owner said "I am getting out and will only be selling rebuilt and new units. I can't get decent parts anymore. The Chinese stuff is killing my reputation." He gave me my money back. That was a Lucas alternator. I bought a GM 12si alternator to put in its place. I got the best price from Auto Zone. That unit failed twice in a year. I am a cheap skate so I tried to save money. Got sick of replacing alternators. The original lasted 25 years. Put a Bosch in and it was there 5 or 6 years later after I sold the car.

Almost Identical we settled on Bosch do to low incidence of comebacks,and our local rebuider,our expierience was same as yours,high failure rates,short life expectancy.