Thowing belt at high RPM

Discussion in 'Troubleshooting & Diagnosis' started by weasel78, Jun 21, 2008.

  1. 71RS/SS396

    71RS/SS396 Veteran Member

    Aug 26, 2008
    Wake Forest NC
    I'll about bet that is your problem. Find an oem alt bracket, the aftermarket chrome junk never fits or lines up correctly.
  2. FlaJunkie

    FlaJunkie Veteran Member Lifetime Gold Member

    Mar 24, 2001
    Rockledge, Florida
    <SIGH> This brings back old, bad memories...

    I had this problem in the first few years of owning my 70 Z28. But I didn't throw a belt; I broke the water pump bearing. Probably 4 or five times. And no, it wasn't too tight, in fact the deflection was perfect. The last time it failed, it took out the stock radiator.

    No one suggested pulley misalignment to me; I thought a rubber fan belt could take a lot of distortion. One parts store suggested a notched V-belt like the ones they use on a Corvair. I tried it and never had another problem with the belt, the water pump, etc.

    <SIGH> :whine:
  3. camaro79Z28

    camaro79Z28 Veteran Member

    Mar 17, 2010
    valley city ohio
    my experierce being and old fart it is useally the alternator is out of alignment, the bottom bolt (pivot bolt) which is threaded into the head and there is a nut that goes on it, lossen up the nut and see if you can get a thin wrench on the welded on nut next to the head this nut keeps it from going to far into the head and back it out a couple of times and see if that works, if not try backing out another few turns, when all is said and done and the belt stops coming off take an eye measurement and pull your alt off and put a flat washer the thickness you need on the back side of the pivot bolt, did this with all my big block chevelles and it works
  4. greencamaro1981

    greencamaro1981 Veteran Member

    Jun 2, 2010
    i had the same problem my car was throwing the belt every shift first i found that the new belt was to wide so i went to an ag bely like a lawn mower belt most parts stores have em and bout same cost but they are narrower than auto belts. next i over tightened the piss out of em fixed it. now im in the process of putting a serp kit from a 90's truck in it to solve the hard to turn ps at idle issue with the saginaw pumps well good luck
  5. msb80sc

    msb80sc Veteran Member Lifetime Gold Member

    Feb 24, 2002
    Saluda, Virginia
    Was reading this thread and the reference to Alan Grove. Been putting off getting some of his brackets, so I went shopping online. I found had a 10% off sell on Alan Grove and 25% off shipping. Mid mount alt and p/s brackets were $108 with shipping.
  6. kawboy

    kawboy Veteran Member

    Apr 2, 2010
    I also had the same issue on a 406 SB. Switched to the March underdrive serpentine kit and never had another problem. Plus it also looked good.
  7. Camaro11

    Camaro11 Veteran Member

    Jul 10, 2003
    Atlanta, GA, USA
    I put on a Top Cog belt and was told by a mechanic that it was unsafe because
    the belt was 'losing pieces'. Needless to say, I never went back to that shop.

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