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View Full Version : Alternater belt problems......HELP



Hustler
05-13-2002, 07:37 AM
When I pulled my motor this year I had noticed that my crank pully was starting to crack around the bolt holes so I bought another one and I changed the alternater bracket which gives it more support than I have ever had, the pulleys are lined up better than they have ever been but yet I cant seem to keep a belt, it continues to spit the belt off, any have some insight on this? Thanks
Hustler

froggystyle
05-13-2002, 07:53 AM
You could be overtightening it now that you have the support and leverage. I believe that at full tightness you should have a 1" deflection at the middle of the span.

Hustler
05-13-2002, 08:09 AM
Thanks froggy, I never really thought of that.
Hustler

Blown509Liberator
05-13-2002, 09:40 AM
Also if the belt is two wide it till toss it.

cncer691
05-13-2002, 12:20 PM
Too Tight, huh? I need to try that, because I lose my alternator belt every time I go out. And I never notice until I gewt back to shore.

Boater Bill
05-13-2002, 12:37 PM
Hustler, I know you have done some work on your motor since last year, are you now making lots more power? I had the same problem with throwing belts when I stepped up in power. Couple of suggestions. 1" deflection is too much in my book, .5" is more like it. Blown509 is right, check how the belt rides in the pulley. Too deep and you eat up the belt, too shallow and off she comes on the first throttle whack. The belt should be just a couple of RPH's up outta the groove. If your pulleys are really lined up (check real good) and the pulleys are straight(no runout)
you can slow the belt down by changing the crank pulley, alt pulley, or both. I'm running Moroso pulleys on both and they cured my problem, haven't tossed a belt since I installed them. Good Luck!

wideopen545
05-13-2002, 06:05 PM
use a underdrive pulley in other word slow it down had the same problem went with the moroso pulley worked very well good luck tim

wsm9808
05-13-2002, 06:38 PM
I was having trouble tossing the belt on my Camaro. Had the pullys perfecty in line and even changed to all deep groove undriven pulleys before I found the problem. It never dawned on me that the QUality of the belt mattered. I had just gone down to auto Zone and bought "a belt", and it cost about 4 bucks. we got to talking about it on the Camaro board and several others had been through the same deal and recomended getting a Dayco top cog belt. I put one on and it has yet to sling off, even with the stock pullys back on and turning 7000 rpm. Belt cost around 17.00.

bajaruner
05-13-2002, 10:22 PM
Hustler,
I have yet to see a alternator belt come off if you do the following. Run a quality belt, I recommend Gates, not the stuff you get at cheap brand X parts stores. Make sure that the belt sits into the pulley groves, not flush, above, or too deep, the last thing you want to do is pinch the belt. Make sure you have both straight and consistent alignment, In otherwords check that there's not to much endplay in both the alternator, and the crank<~~(longshot I know but I've seen crazier things), and that the alternator is not mounted crooked with a slight twist, the belt has to enter the pulleys straight, and no viberating at hi-rpm. Make sure the pulleys don't have any run out (up and down movment). And last run about 7/16" to 1/2"max of belt deflection. I don't feel a underdrive pulley in your case is a cure, just a bandaid.
Hope this helps.

froggystyle
05-14-2002, 08:03 AM
Now I feel a need to justify the 1"!
I meant 1/2" up, and 1/2" down, for a total of 1" deflection. It is not very much at all if you look at it that way.
Good advice on belt selection guys. One thing to consider with an underdrive pulley is that you will not be making as much juice with your alternator. For most, this works great, but I need all the charging at idle I can stand, and I understand that you are considering adding a stereo system as well.
You are bright, I bet by now you have the dilemma solved.

Hustler
05-14-2002, 08:46 AM
Thanks for all the input guys I will try and get it fixed next week, I think finding the right belt is going to do the trick it's just finding that right belt that could be fun.
Hustler