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Throwing your fanbelt at 9500 rpm? Free fix for tech week.

Discussion in 'The Hokey Ass Message Board' started by Bucksnort, Apr 13, 2010.

  1. Bucksnort
    Joined: Dec 24, 2007
    Posts: 3,302


    OK,not much tech here but it is basically free, simple and easy.Not only did this work on my 9500 rpm G/MP 287" but it works on just about any combo w/o serp belts.
    Got 4 pics.The 2 with the orange generator bracket is off the race car and bottom 2 are off my 454 1970 Chevelle.Constant problem in modified production was that you had to run street equipment including charging system.Generator in the case of my 57 chevy.After numerous belt tosses I drilled a hole in bracket just above where the fanbelt ran and bolted a stud/cutoff bolt,etc.Position just above the belt pretty much in the middle of the belts long run to the generator.Never lost another belt over many runs at 9000 plus.I will continue to use this when I get the 57 back nostalgia racing.
    Same with the Chevelle.6200 rpm motor.Flipped the belt a couple of times at the drags.Welded a stud to a plate and drilled hole in alternator bracket.By loosening bolt you can adjust spacing to the belt.I close it up to race and back off a bit on the street.
    Sometimes the belt gets a little shiny but never tore one up.And yes,I do spend effort to get things lined up.I did run deep pulleys on the 57 and have got to get a deep alt. one for the Chevelle but have not lost one since doing this.
    That's it,stupid easy and free.

  2. redlinetoys
    Joined: May 18, 2004
    Posts: 4,301

    from Midwest

    Interesting fix, but...

    ...worthless without a video of a 9500 rpm G/MP 287 making a pass with VOLUME!
  3. 4 pedals
    Joined: Oct 8, 2009
    Posts: 760

    4 pedals
    from Nor Cal

    I agree! I want to see that 9500 rpm pass!
  4. blt2go
    Joined: Oct 27, 2009
    Posts: 551


    i'm in, and make it loud.

  5. BlownMopar71
    Joined: Feb 24, 2010
    Posts: 16


    With or without the load bang at the end.
  6. Cool fix,,and simple and cheap as well.
    That is what engineering is all about!

    Joined: Aug 22, 2009
    Posts: 2,601


    Did ya try a better belt?
  8. cool, thanks.
  9. Wonder how much HP loss there is with a belt dragging across a bolt at 9500rpm.
  10. Bucksnort
    Joined: Dec 24, 2007
    Posts: 3,302


    Wish I had one of mine.It was the days of 8mm and super 8 movies.You tube has a bunch that gets me in the spirit.

    Ha Ha.Honestly never blew a motor.Broke a lot of valvetrain.

    A bazillion.Once they get tossed or flipped,they are junk.

  11. pauls fords
    Joined: Jul 7, 2009
    Posts: 183

    pauls fords

    The easier way to fix something like this is to use an OVERSIZE PULLEY on the alternator, The belt is going around it 2 to 3 times faster than the crank is turning, a belt can not make the curve that fast, Sense from an old drag racer......try it, the pulleys are avalible at Summit or Jegs
  12. Bucksnort
    Joined: Dec 24, 2007
    Posts: 3,302


    Ran the 57 before there were oversize pulleys in the 60's.Did use Stahl/Moroso pulleys in 70's.
    The Chevelle is bone stock,have a 375 alt pulley but have not put it on because this is so simple,different and it works.
    I also have been racing since the 60's.Don't want new stuff,want to do it the way I did back then.[​IMG]
    Joined: May 13, 2002
    Posts: 3,257


    the top pictures of the early bracket.brings back memories,that's what we did in high school.
    Hi winding 327 with a "30-30" cam,4:11 rear,4speed. 15x10 Cragars with N50x15's !!
  14. mrpowderkeg
    Joined: Mar 11, 2009
    Posts: 178


    I'm not trying to start a brand war, but I'll mention this to my gm buddies, it seems that throwing belts is common with what they have. I've never had a lick of problem with 302s, FEs or 460s, many were high rpm screamers, Do GM products run a longer than typical belt?
  15. Bucksnort
    Joined: Dec 24, 2007
    Posts: 3,302


    That's a good question.Don't know about length differences.I know that there is a lot of variables such as pulley alignment,different water pumps and pulleys and the angle of the mounting of the gen/alt.Sometimes gotta shim brackets to help align.
  16. Licensed to kill
    Joined: Oct 4, 2009
    Posts: 214

    Licensed to kill
    from Alberta

    Sounds like perhaps mopar guys are used to hearing "loud bangs" at the end of a run so they think all engines are like that:p:D. I had assumed that "BlownMopar71" refered to having a blower, apparently not:D
  17. Unless you are lucky enough to run a 426 Hemi, Mopars don't generally need to have the pee wound out of them to make power (maybe 273's), so the wee chevy's are kind of amusing.
  18. 56sedandelivery
    Joined: Nov 21, 2006
    Posts: 6,695


    Very common problem in the 60's-70's, especially with SBC's. And, a very common approach to dealing with it. The oversize pulleys on the generators were really intended to slow them down, so they would'nt throw solder, the deeper pulley grooves were secondary. If anyone remebers, the 283's (like Bucksnorts' bored out 283 to 287), had the rivited pulley on a hub. You could'nt really call them balancers or dampeners. Those pulleys were often bent, and prone to wobble from being beat on and pulled off the crank snout. I think that probably had a lot to do with tossing belts also. I used to have a 265 that would toss belts, and a simple bolt on the tension bracket did the trick; it used to really polish the bolt and wear into it. Butch/56sedandelivery.
  19. AJofHollywood
    Joined: Oct 3, 2008
    Posts: 640


    A SBC doing 9500 rpm? I see it loosing more then a 1/2" fan belt!

    Plus a couple of bolts welded to the frame isn't going to keep the belt from coming off. I'd think it would do more damage to the belt when they make contact. Rubber and friction don't mix.

    You should be installing a serpentine belt set-up. But that might cost more then $5...
  20. hotrod40coupe
    Joined: Apr 8, 2007
    Posts: 2,562


    Seems to me that a roller bearing mounted on the stud would eliminate a lot of the wear on the belt.
  21. It was not uncommon for a super stocker to turn 10 grand with a small block,,they used to literally scream before they popped the clutch.

  22. Look up Gene Scwhartz. 9500 plus sbc - he's the man - drives with roach stompin cowboy boots and wrings the hell out of his 5 speed
  23. gasserjohn
    Joined: Nov 9, 2008
    Posts: 1,219


    ''have been racing since the 60's''
    donot want new stuff ,he wants to do it the way he did backintheday
  24. Ford does generally mount the alternator much closer to the pulleys than the early GM stuff and aren't any where near as prone to throw belts.
    Joined: Aug 28, 2005
    Posts: 1,866


    Great tip. Thanks for sharing.
  26. Pete1
    Joined: Aug 23, 2004
    Posts: 1,952

    from Wa.

    Assuming you have good pulley alignment and can hold good tension, you might try
    link V belt...It does not flutter at high speed like a conventional V belt.
    A V belt track will grow or expand coming off of a pulley at high speed. When this happens,
    it will start fluttering or wobbling. This can be easily observed with a strobo-tach.
    Years ago I was modifying drill presses for high spindle speeds around 10K rpm for drilling
    .010 diameter holes in various aluminum alloys. I used link V belt because it did not cause vibration in the spindle at these speeds. It runs true on track.
    Attached are a couple pics of the belt setup driving the power steering pump on my roadster. I only turn 8K but have never had any belt problems.

    Attached Files:

  27. This is funny. I have seen this trick on half a dozen or more old race cars and several hot boats and always wondered what the extra stud or bolt was for or what had fell off. I think this is a trick that a lot of street racers did or at least shade tree racers. Thanx for the info, I like learning new things.

  28. Bucksnort
    Joined: Dec 24, 2007
    Posts: 3,302


    Give gasserjohn a cee-gar.
  29. claymore
    Joined: Feb 21, 2009
    Posts: 896


    Simple but effective cure for the chevy belt throwing problem. You new guys are forgetting that we didn't have billet, modern belts, and serpentine drive stuff back in the day. And remember the belt would only come into contact with the bolt for a few seconds at most if it was starting to come off it was not in contact at all at lower speeds and if the bolt stared to show signs of wear throw it away and put in another and go RACING.

    Good one from a Real racer.
  30. Bucksnort
    Joined: Dec 24, 2007
    Posts: 3,302


    Thank you,claymore.Right on target.

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