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.

 

[AuroraGirl]

^^^ 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.

i dont advise it
but as it stands CS130 have a heat problem that kills them
Rebuilds just using cheap parts dont make that better
There is a modified CS130 case by a company online which makes them cool better, youd need to spedn a lot for their custom alternator
One could rebuild it going forward and enjoy the benefits for a long time, but its not something id buy another every time (who knows how long its on the market, etc)



id persoinally go shopping in a yard if they have one near you for old alternators from trucks with the 12 and 6 oclock ears and get one. the pulley swaps directly over since you need a v belt (from your 12si)

The CS130 was replaced wit hthe CS130D which was better, but still dies eearly because of heat. The AD230 is best, but i think it may require a special case to get the same spacing with the ears and in the same plane as they are on the cs130

The reason I advise it over the other is the wiring is much better setup, the charging is more intelligent, it uses more optimized use of the case because of the way the stator is wound (delta)The thing has more features. such as no belt loading until staeted, vs a 12si will begin loading the belt the moment you crank the key. when you turn on big eleectrical loads it smoothly ramps up output to meet it rather than plunge the alternator under load , better on old v belts.

THey also in 1087 had a cool v belt

You must be registered for see images attach

You must be registered for see images attach

Poly-V belt or multi-v
They are still v belts but wider
Serpentine belts look similar but require tensioners and are much more complex in their construction, and can drive pullies on the smooth side

 

[Ricko1966]

i dont advise it
but as it stands CS130 have a heat problem that kills them
Rebuilds just using cheap parts dont make that better
There is a modified CS130 case by a company online which makes them cool better, youd need to spedn a lot for their custom alternator
One could rebuild it going forward and enjoy the benefits for a long time, but its not something id buy another every time (who knows how long its on the market, etc)



id persoinally go shopping in a yard if they have one near you for old alternators from trucks with the 12 and 6 oclock ears and get one. the pulley swaps directly over since you need a v belt (from your 12si)

The CS130 was replaced wit hthe CS130D which was better, but still dies eearly because of heat. The AD230 is best, but i think it may require a special case to get the same spacing with the ears and in the same plane as they are on the cs130

The reason I advise it over the other is the wiring is much better setup, the charging is more intelligent, it uses more optimized use of the case because of the way the stator is wound (delta)The thing has more features. such as no belt loading until staeted, vs a 12si will begin loading the belt the moment you crank the key. when you turn on big eleectrical loads it smoothly ramps up output to meet it rather than plunge the alternator under load , better on old v belts.

THey also in 1087 had a cool v belt

You must be registered for see images attach

You must be registered for see images attach

Poly-V belt or multi-v
They are still v belts but wider
Serpentine belts look similar but require tensioners and are much more complex in their construction, and can drive pullies on the smooth side

The 84 Camaro alternator I guided him to is a 94 amp 12si with belt drive. It is a drop in replacement for his 10si.

 

[AuroraGirl]

The 84 Camaro alternator I guided him to is a 94 amp 12si with belt drive. It is a drop in replacement for his 10si.

yes, i thought he had a 12si already
The 12 si is just a stronger 12si

There is , however, a delta wound alternator that is the same as these, thats called the 27 or 15si , i think the CUCV came with it. more charging potential with the same size.

The electronics are the same and the wiring too


I am saying the cs130 produces more power at idle (105amp overall) and they are feature-rirch

Also be careful geting used Cs130, a cs121 is not more amps than either the 12si or cs130 and is quite poor at its job

 

[Ricko1966]

Just went and read a bunch of this,it's not his choice of 10si,12si,cs130 etc that is causing his problem. These trucks new with 10si didn't drop down to 8 volts idling. He is not wired correctly,or has some bad wires. Even then something weird is going on because even if the alternator is putting out absolutely nothing at idle,the battery should still be able to maintain over 10 volts. Especially no more loaded than that is. I use 10 volts as failure when load testing a battery. Will the battery hold a charge for a week?

 

[75gmck25]

Good point - the current 10si (or its wiring) is bad, and the simplest fix might be just to use a direct replacement.

Alternator testers at the parts store seem to be unreliable. I think they just check for continuity and maybe some resistance values to see if they are within spec. They don't appear to actually load the alternator and see that the voltage regulator kicks in properly and maintains the output.