onesickpantera

iTrader: (1)

My alternator belt is slipping after a few hours. Then at WFO my voltage drops and I can smell it. Alignment is on and I run it tight.

I did a search and it looks like the belt should ride just under the top of the pulley. This belt rides just over. For some reason my steering and water pump belts ride just under and I have no problems with them. All three belts are the same width so that pulley must be narrower for some reason.

Should I try a narrower belt for the alternator? My main concern is it will ride too low in the crank pulley.

Thanks

Sledge Hammer

I don't think the narrower belt will be any problem. Not sure how a belt can slip if it is tight unless you got some fluid, like oil, getting on it.

FIXX

iTrader: (2)

If you can read the belt # if its a 15??? drop it down to a 13??? and it will ride deeped in the pully.. i like the good year gater back's they seem to run cooler..

Young Performance

I like to use the Top Cog belts. You should run the narrowest belt you can as long as it doesn't bottom out in the pulley. The belt is supposed to grab on the tapered sides and not touch the bottom of the groove. If it does touch the bottom, it will continiue to slip.

Also, check the alternator when it gets hot to be sure something isn't causing it to seize and become hard to turn. It could spin freely when it's cold, but become hard to turn when it heats up. Just a thought.
Eddie

ezstriper

try getting a deep groove performance pulley, with proper belt should cure the problem

onesickpantera

iTrader: (1)

Thanks guys. The belt I have now is 17/32(Dayco 17405) wide so I may try a 15/32 and see what happens.

No idea why my alternator pulley is narrower as they are a set of billet pulleys.

mike tkach

iTrader: (3)

i had the same problem,i went to the narrower belt,problem cured.

ezstriper

probably chinese junk....get it even when you but quality parts !!

onesickpantera

iTrader: (1)

Still chasing my tail on this. Pulled the alternator at the end of last year and had it checked. The guy loaded it down hard and said it was fine.

So, put a new belt on this year and right away the belt squeals past 3000 rpms and voltage drops. Once on plane if I gradually back off the throttle the belt will stop squealing and voltage will climb back up. Then if I SLOWLY give it throttle again the voltage will maintain. If I give it throttle quickly the voltage drops quickly to 12.

How can a belt slip that bad? Plus, there are no black marks in either pulley. I thought maybe the pulley was spinning on the alternator shaft but there is no evidence of that.

I'm stumped!

onesickpantera

iTrader: (1)

Thought I would do an update as I finally figured out the problem, just in case others have a similar issue.

My front belt goes around the crank, water pump and power steering. Middle belt goes around water pump and alternator only.

The front belt was actually the problem. At high rpm it was slipping in the water pump pulley making my water pump barely spin. In turn, since my alternator runs from the water pump the alternator was barely spinning.

I took the water pump pulley off and had a few thousands shaved off as it was grooved pretty good. Threw a new belt on and it's been good ever since. I can't believe I chased my tail for so long assuming it was the actual alternator belt! I can't count how many alternator belts I bought!

I am going to run a longer belt next year to go around the crank as well. Or, run a crossover(since the water pump seems to do very little) and run everything off the crank.