Thowing belt at high RPM

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

  1. weasel78

    weasel78 Member

    71
    0
    Jun 2, 2008
    Flint, MI
    I think I got it taken care of, but no proof yet. The day I got the new belt on is the day my transmission decided to not go into any gear.....so my trans is now out. I did however wrap run it up to 6000+ rpms in park and it didn't toss the new belt, so I'm hopefull that the spacer did the trick.

    More to come after the trans goes in.
     
  2. 73Z28LT

    73Z28LT Veteran Member

    its usually one of three things:

    Alignment
    Pulley not deep enough
    Belt too wide

    Just my .02
     
  3. weasel78

    weasel78 Member

    71
    0
    Jun 2, 2008
    Flint, MI
    Update:
    The spacer and new belt failed me. Got the newly rebuilt trans in and took her out and spun her up to 6500 RPM in first gear and she tossed it again. :mad: :mad: :mad:

    I'm really starting to hate this belt issue. If I hadn't just dropped a crap load of cash on the trans and new Coan converter, I'd be ordering up a new serpentine setup!!!
     
  4. vegas1974z28

    vegas1974z28 Moderator Staff Member Lifetime Gold Member

    4,563
    73
    Jan 10, 2002
    Las Vegas,NV
    this fixxed my problem. Under 1100 rpms doesn't charge well after that just fine.

    [​IMG]
     
  5. DAWG

    DAWG Veteran Member

    182
    0
    Mar 30, 2008
    Colebrook, Connecticut
    get a long straight edge and run the edge across the crank pulley to the other pulleys.
    then youll find the problem.
    either you got a alignment issue or one of your brackets is bent or your crank pulley is going south.
    [​IMG]
     
  6. smallblk77

    smallblk77 Veteran Member

    203
    0
    Jul 9, 2008
    Middleburg, Fl
    I had this problem with my 75 Camaro a while back. I switched to the pully and belt set up off a 86 Z28 and had no more problems. The setup even worked great on a BBC that was installed in the 86 later on. Used all pullys off the 86 (Alt, Waterpump, Crank and P/S). Allot cheaper than a March system and can be found at any salvage yard.
     
  7. TheFly

    TheFly Guest

    YOu musy have a warped or lose pulley somewhere, if you can see it or not.
    Start swaping parts, even if you just swap on used parts but from a engine not known to throw belts.
     
  8. weasel78

    weasel78 Member

    71
    0
    Jun 2, 2008
    Flint, MI
    So I still haven't solved this problem, I bought a summit alt pulley in hopes this would fix it, but then my master cylinder went and its been sitting since....I'll update once I get the brakes fixed and I get to drive it again. If this doesn't work, I'm thinking its new alternator bracket time, and after that.....March Serpentine setup.
     
  9. 71RS/SS396

    71RS/SS396 Veteran Member

    2,557
    16
    Aug 26, 2008
    Wake Forest NC
    Do you have any pics of the front of the engine and your alt. bracket? If you're using an electric water pump I'm assuming you aren't using the stock alt. bracket
     
  10. weasel78

    weasel78 Member

    71
    0
    Jun 2, 2008
    Flint, MI
    The more I think about it the more I think the alt bracket is flexing. It is stock pulleys through and through. The alt bracket has been modified though, the tab that bolts to the intake has been cut off, so it only mounts to the water pump and alt. I'm almost sure this is the issue and that an new bracket will fix it. But I have to get my brakes fixed before I can prove it.
     

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