I Keep Smoking My Alternator Belts... Why?

[bucket]

Ever since I swapped the 454 into my '84, I can't keep from smoking the alternator belt. I've replaced it a few times now. Doesn't matter how tight i set it, eventually it slips and smokes itself on a cold start and then it's all downhill from there.

It's the same alt and pulley I ran on the old 305, never had any trouble then. Belt alignment is spot-on. I think the only thing different is the 454's crank pulley is larger, causing the alt to spin faster. But the alt pulley is about the same size as any other big block truck, so what gives?

My only other thought is that the battery discharges more on startup, causing the alt to work harder, in turn causing belt slippage. Will a higher amp alt not load the belt as much because it wouldn't have to work as hard? I think it's a 65 or 70 amp unit on there now.

 

[PrairieDrifter]

Do the big block alternators have more output?

 

[firebane]

I think it is time to check your crank to alternator ratio and see where you are.

https://alternatorparts.com/alternator-pulley-size.html

 

[bucket]

Do the big block alternators have more output?

Not generally, just depends on year and options.

I think it is time to check your crank to alternator ratio and see where you are.

https://alternatorparts.com/alternator-pulley-size.html

Hmm, maybe the pulley is glazed. I'll figure out the ratio, but I think I can get away with a larger pulley. Even with the lights and fans on, it charges great as long as the belts not slipping.

 

[RetroC10Sport]

Tell your truck smoking is bad.

My Fiero would smoke alternator belts at random times. I found a Delco belt in the junkyard and that one lasted until I parked the car.

 

[bucket]

Tell your truck smoking is bad.

Hey, I'll take a smoking alternator belt over the old smoking 305 any day!

 

[Don5]

Hey, I'll take a smoking alternator belt over the old smoking 305 any day!

That was a good one Andy...

 

[bucket]

That was a good one Andy...

But tire smoke is even better!

 

[smoothandlow84]

Bad bearing in the alternator?

 

[bucket]

It is quiet and turns free.

I think my battery might just be taking a dump, I can't put the timing where I want it because the battery doesn't have the balls to turn the motor over on a warm start. It's still under warranty too. Maybe a new battery (yet again) and a good belt will take care of it.

 

[Georgeb]

It is quiet and turns free.

I think my battery might just be taking a dump, I can't put the timing where I want it because the battery doesn't have the balls to turn the motor over on a warm start. It's still under warranty too. Maybe a new battery (yet again) and a good belt will take care of it.

Perhaps tour starter is taking a crap if it lacks power on a warm start.
Did you check the pully ratio numbers that were posted? Now about pully wear? Does your belt pull down into any of them too far.

 

[bucket]

Perhaps tour starter is taking a crap if it lacks power on a warm start.
Did you check the pully ratio numbers that were posted? Now about pully wear? Does your belt pull down into any of them too far.

I've noticed a cold start has also been gradually getting weaker since purchasing the battery too.

I haven't checked the ratio yet. Haven't messed with it until today, it started without smoking the belt, so I screwed with other things instead, lol. The belt is deep into the pulley now, but it has been smoked a couple times and has shrunk in size. From what I remember, a new belt fits the pulley correctly.

 

[bucket]

Also, the battery will randomly lose it's charge now. Other than the factory clock and the CD player memory, there is no drain on it.

 

[kdo58]

i was using belts from oriellys, and could never keep my belt tight, change it one from nappa, it was way wider and thicker belt and solved my problem.

 

[bucket]

Looks like I'm spinning the alt too fast, getting roughly a 4.1 to 1 ratio. So at 4500 engine rpm, the alt is spinning around 3K too fast for it's own good.

So I guess a pulley swap is in order. It's also a stamped pulley.