nine8ss

iTrader: (5)

It is good to know that I am in the presence of the almighty himself.

01ssreda4

iTrader: (96)

Whats a stocker rated at maybe 90? Should be plenty. I wonder if they genuinely have a fault in the design of them.

pdxmotorhead

Most truck alternators are wound/designed slightly different to make them excite at a lower RPM.. It could be as simple as the truck alt is being overdriven by a few percent more than it would in a truck.. Also if everything else is the same ,, is the truck crank pulley bigger than the stock F-body?

01ssreda4

iTrader: (96)

So lets get this straight, the alternator can't keep up.....with the lights......at WOT?

It could be a faulty voltage regulator inside the alt, fine, but he doesnt need a fricken truck alternator!

00pooterSS

iTrader: (40)

All true. He'll understand once that OEM alternator fails and can't find any answers as to why every single replacement one he puts on it fails almost immediately. Everyone will end up in the same boat at some point. There's a reason my alternator thread is 50 pages long. His tune will change.

And no I didn't need the 145, the 90 would have sufficed, but after roughly 10 tries with replacement 90's I had to find a different approach. What led me to the 145 was the abundance of them for $40 (at the time) and I needed to try something different to see if it was for sure the alternator or something else. The used 145 was the last alternator to ever be on that car and the end of the alternator issues. The car was totaled some time later and about 30k miles later, still 0 issues from the alt. I'm sure an OEM 90 would have worked, but they were around $500 at the time and I couldn't chance burning one up and not being able to warranty it. So I needed a cheap way to try out an OEM unit, a used truck unit was the answer, used OEM truck units were/are everywhere. Good luck finding one from an f body compared to finding one off a truck.

G Atsma

It IS puzzling! I know squat about alternators, but ask this- Besides that which determines the amperage it puts out, is/are there components that are different that might be contributing to the longevity of the truck unit?

01ssreda4

iTrader: (96)

I have a 6.0 with the upgraded sized unit, I have an fbody with the stock unit. Theyve both been replaced once. Weird huh.

00pooterSS

iTrader: (40)

What brand is your replacement f body alternator and where did it come from? Normally the replacements fail quickly and continue to do so.

00pooterSS

iTrader: (40)

To add to my above post, my OEM 90 amp on my camaro lasted just fine, the only thing on the entire car that changed between no problems to problems was the alternator. Nothing was added on or changed. I only changed the alternator because the power steering leaked on it and I was concerned the alternator would go out, it actually never had an issue, I was just being proactive and swapped it thinking I would be avoiding being left stranded. And that's when the problems all started. And putting an OEM alt back on it cured all the problems. Again, nothing was changed but the alternator from good, to bad, and back to good.

I don't think that either alternator actually outlasts the other in their given OE habitat. The OEM f body alternator usually lasts almost forever and the truck ones do too. The difference comes into play when you introduce aftermarket/rebuilt/replacement alternators. The replacement f body alternator fails almost immediately for most, the replacement truck alternator typically lasts. I don't know if there are higher quality components in the truck alternator or if it's just the simple fact that you aren't using as much of the alternators capacity. For example: if you are using a f body alt and pulling 60 amps, you are at roughly 70% of the alternator capacity, with a truck 145 you are closer to about 35-40%, so the truck alternator is much happier at that load. For what it's worth, I regularly pull 150-200 amps on my junk yard alternator without failure (added on 07+ electric fans and a very large amplifier that pulls somewhere around 100 amps)

In the camaro I had a small amp and that was it. I never had a problem with the amp and the OE alt or the truck OEM alt. I disconnected the amp with the replacement alt's and they still failed.

01ssreda4

iTrader: (96)

orielly brand, specified a "new" one. It wasnt cheap either

G Atsma

Sounds like aftermarket componentry might be at fault. Blowing dollars while saving pennies.....

00pooterSS

iTrader: (40)

I specified new ones too and they all went to ****, then I tried rebuilds after several "new" ones. None lasted. The new didn't do any better than the rebuilds. If you look through my alternator thread you'll see a lot of people have problems with the replacement f body alternators, you apparently got lucky.

I tried them from a commercial supply house that we use at the shop, autozone, oreilly, napa. I got at least 2 alternators from each place. I tried each flavor they offered and none held up more than a couple weeks. Every time I tested wiring and amp draw etc and never found anything wrong with the car. Several people have done the same, and all have fixed it by just getting a quality alternator. Haven't yet heard of anyone finding anything wrong but the alternator itself (when it comes to repeat failures, seen other threads with different charging issues where other things were found).

G Atsma

Maybe there was a rebuilder supplying most parts houses in your 2 or 3 state area putting shitty parts in their alternators.

00pooterSS

iTrader: (40)

I imagine there was one main supplier for all the rebuilders and that explains the mass of people in the alternator thread that all experienced the same pattern failures with replacement alternators.