My alternator keeps chewing belts..Please Help!!

Hey Guys,

I am still de-bugging out the new 235 in my 50 Chev, and while little things have come up and been addressed, I cannot for love or money get the alternator to line up correctly and stop eating the belt!!! I have tried to shim it with washers, adjust per measuring tape, eyeballing...I have even gone as far as to loosen all the mounting hardware and starting the motor, figuring that maybe it might track itself. But it keeps eating the belts!!! The motor is a pressure 235 with an aftermarket alt bracket, the bottom looks kinda like the letter f on its side mouting to the block and the top looks to be the stocker from the generator. I looked on ebay for new brackets, figuring that maybe somebody re-invented the wheel and made something better, and maybe they have but I am on a tight budget and 100 bucks + shipping for a car thats going into Winter storage in a couple of weeks seems a little off. So i am looking for a little free advice on a fool proof way to get this thing right so I am not changing belts every 30 to 50 miles on the way to the Hunnert, which is about 150 miles from the house!! Somebody told me to try a cheapo laser pointer to see what is lining up with what, but I havent tried it yet, and no I am not over tightening the belt, actually it lasts longer if I leave it almost scarry loose!!! So some great advice would help me a ton!!! Thanks!!!!

 

If the brackets are real long, it may be twisting. I'm not much help, that is just my guess...

 

Is the harmonic balancer in good condition and lined up where it should be? Do you have the correct alternator bracket - the 53-54 is different than the 55-62.

 

I had this issue once..
in my instance it was rust pits down in the groove of the pulleys..

look for pits.. which can act like sandpaper to the belt..

 

It's hard for me to imagine the belt getting chewed this quick when you have to be (by your description) at least close.

I have a home built bracket and it's not exact. Yeah, I need to fix it but it's been off center for years and it's still running the same belt (I have another in the trunk).

Not tight enough? Slipping belts will go IMO faster than one just slightly off.

 

Use different lengths of straight edges going from the face of the crank pulley to the faces of the other pulleys. Cheap wooden yard sticks or paint stir sticks on their edge works well for this.
Make sure the "v" and bottom of each pulley is very clean.

Make sure you have the correct width of belt for your pulleys. If you don't know how to measure contact a good NAPA counter man to help.

Standing out of line of the fan, gently race the engine and check for alternator flex in the brackets

Finally, do not over tighten the belt!!


Good luck.

 

Post a side view and a top view picture of the whole magilla for us.

 

I have had this happen to me. In my case it was a pulley that had become loose, and made the center hole a little off. It would eat a belt in 10 miles, and I couldnt see it being off with the car running or shut off. So..... look at your pulleys real close, one might be barely loose or not quite center.

 

Post some pictures of your setup.

 

the pulleys are clean, I sanded and painted everything as i re-***embled the motor, and actually I am not sure if it's the correct bracket...it is the same one from the old 216 that worked with that block. As far as the harmonic balancer goes it was installed on the black and looks to be ok, it is not wobbling all over the place. Here are the pics you guys are asking for!!! Sorry but kinda hard to see unless I were to take everything apart, but here ya go & thanks!!!

 

Ok the black **** that you can see is burned rubber from old belts and I have tried to use smaller and wider width belts, too small and they are gone in moments, so the wider belts hold on longer. I can even provide the part number for the belt from Pep-Boys as I always have 2 on hand!!

 

It may be the angle or my crossed eyes but it looks like it is crooked. You've measured out the right distance but it isn't straight.

 

Your alternator is crooked and that is what's doing your damage. You can clearly see at least from what you posted that it's about 5 degrees tilted inward. I imagine that pulley is chewing thru the belt. Get the alternator parallel with the crankshaft.

 

Make sure its not over tight. You should be able to wiggle the belt fairly easily with two fingers. Look at the groove on your pulley if its a high shine almost like a polished finish than your belt may be to tight.

edit** after checking the pics i agree, your alternator doesnt appear to be lined up straight, it looks to be tilted inward, Im sure that could be a part of your problem.

 

I have been looking at that thing now for a couple of weeks, and until I saw the pics I never saw it, but to me it looks crooked as hell from the pics. I need to go and recheck and do some shimming to get that thing straight!!

 

I'm not sure, but it looks like the pulley on the alternator is intended to be used with a wider belt. The bend radius of the belt around the alternator pulley appears to be pretty small, which will also make the belt wear faster. A larger radius also means you don't have to have the belt quite as tight either.Does the lower alternator bracket have a through bolt with mounting points on both sides of the alternator, or just on the front? If just on the front, overtightning will definitely tend to pull the alternator out of alignment. Basically it "pivots" on the two front attachment points, with nothing to keep it from twisting when you tighten the belt. Also, the water pump pulley (or at least the hub) looks like it might actually have some rust pits in it that have been painted over, which makes me think that the pulley might have some as well. I know you said it doesn't, but I'd look a little closer. And of course, there is the misalignment issue as well........

 

I chased this problem on a sbc. Changed all pulleys, brackets and belts several times. The problem was as bad ground to the ch***is. Check all conections and the problem should be resolved.

 

I see 2 potential problems or at least things to check.

1. your bracket appears to be from the 55-62 and will work, but needs to be shimmed and the holes oblonged - that usually creates a "crooked" alternator. Might want to change brackets or shim this one
2. the alternator pulley is not from a 3/8" belt like your water pump and balancer are. Looks to be from a 5/8" application. I would change that and see if it works and if not, do something with the brackets

 

Doubtful. I'll entertain any explanation as to how a bad ground could cause this.

 

I wanna see photos of the failed belt. It's may be possible to diagnose the reason for failure by determining the failure mode.

Bob

 

Well, the belts are being ground up, so maybe ---, nahh.

Bob

 

The alternator is trying to overcome the resistance. A delco alternator will actually stall the pulley I have seen the belt stretch and rise over the pulley. The clue to me was that the bely lasted longer when you left it looser. Your fresh engine has new paint, hence a poor ground. It seems counter intuitive but check it out.

 

I think its a combo of wrong pulley sizes. The belt you have on it now rides high on the fan, and low on the alt. and I bet it rides somewhere inbetween on the crank. There is no constant place for the belt to ride, so its going to eat itself.

 

I have to agree with wrong width pulley on the alt.
Change it and see what happens.
Things do look a little out of alignment but not enough to give you such short belt life.

 

I'm with Ebbsspeed on the width of the belt and the notch in the pulley. Is the belt cross section appropriate for that groove? Photos can be deceiving but the alternator sure looks skewed.

 

hate to sound like a yes man but it does look like your alt is turned inwards and needs to be pulled out. the front/back alignment looks good though.

also, im not saying you are over tightening but i did that as i had to make my own generator bracket when i put a 4bbl on my '55. ive always used a bar to get my belt tight on every car so i did the same thing. damn belt would go 1-5 mins and flip over then eat itself alive. pissed me the hell off till i went with a slightly bigger belt and just used my hands to pull the generator tight and cinch it. hasnt had a problem since

 

had the same issue with a ford inliner...mine wasnt ****ed as much as yours is and was chewing a belt a week....ended up going the junkyard and getting the the correct brackets and pulleys to fix the problem.......dave

 

Alt. is crooked and you need to change the alt pulley to match the waterpump pulley and it looks like the belt is sinking to far in both pulleys.

 

Run a temporary ground wire from the alternator directly to the battery ground. If that solves the problem, clean a path from the battery from the battery to the alternator. Paint is a ground killer.

 

If the ground is bad, the alternator cannot charge at full capacity, if at all. Hence the effort to turn the alternator is less. No different than if you were to disconnect the charge lead. I still disagree. You had another issue.

Regarding this thread, it's quite obvious to even the most casual observer that the belt-chewing issue is a combination of belt/pulley width mismatch, and pulley misalignment.