Weird noise when I rev my 425 high, help!

Discussion in ''Da Nailhead' started by BlackRiv, Jun 3, 2005.

  1. BlackRiv

    BlackRiv The Black Stallion

    Ok so here is the deal when I rev the engine pretty high sometimes I hear this noise where it almost counds like brush is getting ran over by the car ( a binch or ting noises) kid of, but there is no somke and it runs fine and everything I just doint know what the heck the noise is, is it bad

    thanks, DJ
     
  2. DugsSin

    DugsSin Well-Known Member

    Reving a Nailhead without any load is a HUGE NO NO :rant: :af:

    This is about the only thing that will pull the bottom end apart.
     
  3. nailheadina67

    nailheadina67 Official Nailheader

    :puzzled: I think he meant while driving it.........maybe a belt is slipping? Could you be more specific in your description?
     
  4. tmcclu

    tmcclu Well-Known Member

    Could the noise be pinging? Tim :Do No:
     
  5. BlackRiv

    BlackRiv The Black Stallion

    ok well it does it when I am sitting still, in gear, or in nutral while moving, I doubt it is a ping noise. It is a hard sound to describe it sounds almost like somthing is shredding, like a cable or somthing like that. Like I said it is simialr to the sound if you ran over a bunch of brush
     
  6. r0ckstarr

    r0ckstarr Well-Known Member

    Anything in the way of your fan blade? Fan shroud to close? Those high rpm's may be causing the fan blade to pull the shroud closer if it is loose? Stock fan blade or a flex fan?
     
  7. BlackRiv

    BlackRiv The Black Stallion

    that could be it, it is the stock fan blades, waht should I fix?
     
  8. Smartin

    Smartin antiqueautomotiveservice.com Staff Member

    Check motor mounts!
     
  9. Dale

    Dale Sweepspear

    Rattles and sounds irritate me, we must figure this out...

    [​IMG]

    A loose fan, or shot fan clutch?

    What about a loose, shaking pulley or harmonic balancer?

    An alternator or water pump bearing sensitive to high rpm?

    The torque converter? :confused:
     
  10. nailheadina67

    nailheadina67 Official Nailheader

    If you have a/c it may be the pulley bearing on the compressor. Mine made wierd noises before it siezed up one day........it took about 20 miles after it started. Thank God I wasn't on the interstate or someplace where I couldn't shut the motor off immediately. The smoke from frying belts poured out instantly from under the hood.......the bearing got so hot it welded itself together and was sizzling when I opened the hood! Talk about an awful noise :shock:

    Try running it with the belts off and see if the noise is gone.....just don't drive any distance that way or you'll overheat it fast. :bglasses:
     
  11. Babeola

    Babeola Well-Known Member

    I agree with Joe on the belts. A loose alternator belt or alternator on the way out will squeal like crazy at higher rpms.
     
  12. i agree with smartin
    nailheads like to twist on the mounts and then everything sounds like its coming apart
    also check the flywheel cover and the bolts that hold the flywheel to the tourqe converter
    that folws through the car and is hard to pin point as well
    Greg
     
  13. bob k. mando

    bob k. mando Guest

    if your fan blade is getting into the shroud any cursory examination of the shroud will show it.

    rule it out, one way or the other.
     
  14. BlackRiv

    BlackRiv The Black Stallion

    its not a squeel tho I described it earilier, it is like a shreeding noise and it is not constant when it happens (sounds are randomly placed) and the sound stayes there a while after it is reving down.
     
  15. r0ckstarr

    r0ckstarr Well-Known Member

    Do you see any marks on the inside of the fan shroud that looks like the blade was hitting it, or rubbing against it?
     
  16. scirocco

    scirocco Member

    As a new Nailhead owner ('63 225... 401/425), can someone explain *why* revving a nailhead no-load will frag the bottom end?

    I'm generally very conservative rpm-wise anyhow, below 4000 is my personal rule..

    The implication was that it's bulletproof under load (nitrous load? forced induction?), but will come apart if revved...
     
  17. BlackRiv

    BlackRiv The Black Stallion

    so they are fine under a load at high RPMs?
     
  18. nailheadina67

    nailheadina67 Official Nailheader

    Before I rebuilt my new motor about 5 years ago, I revved my old one up to 6,500 in first gear for about a minute......I didn't care if it spun a bearing, but nothing happened. It just smoked like hell b/c it had 3 broken rings. :3gears:

    It's not good to rev ANY motor up too high without a load on it. I don't think the Nailhead is any more or less likely to explode than something else, but if I had to speculate I'd say it's less likely. I've heard stories of thrown rods, spun bearings, burned pistons, but I've never personally had that problem with mine in the last 29 years I've owned one. I try to keep it below 5,500 although it will rev higher with the stiffer valve springs I have. No point in going that high....there's no power up there.

    If you want to hear a story, before my dad gave me his '66 Riv, he used work until late at night with my uncle. Sometimes they would work for 2 days straight until the job was done. Anyhow, one time 30 years ago before 24 hour mini marts were even thought of, he was about 50 miles from home and ran out of oil pressure. (dad was not one for oil changes) Anyhow, he made the drive home at 4 AM with no oil showing on the stick and the oil pressure guage wasn't even moving. The next day the engine took 4 qts. of oil.........assuming the filter holds just under a quart, what was left is all the lubrication that 425 had. Well, it wiped the cam out and the lifters were really rapping after that happened........the noise never went away after that. Before he gave that car to me, we drove it like that for over a year and although it sounded horrible, it ran great. No spun bearings or thrown rods. I even creamed a camaro on the way to school one morning with it like that! :Brow: When I finally was able to talk him into letting me rebuild it, I was really surprised at the condition of the crank. The bearings were wiped out, but nothing was scored. The rocker arms, camshaft and lifters however were totally wasted but I think that was due more to sludged up oil passages than lack of oil. The motor only had 66,000 miles on it but I wonder how a different motor would have fared under those conditions being driven 50 miles without oil pressure?

    Nailheads are definitely tough as nails, but revving any motor in neutral is only asking for trouble. :TU:
     
  19. BlackRiv

    BlackRiv The Black Stallion

    well thanks for the story! that might help alot because I do have a hydrallic lifter that is making a clicking noise when I first start the motor somtimes ( I think it isn't filling with oil) so that could be it but I am going to replace them When I put my Portand polished heads on it! and anyone know waht the advantages of the bronze sleeved rocker arms are?
     
  20. nailheadina67

    nailheadina67 Official Nailheader

    That's something Nailheads just do normally.......both mine did that. I found that keeping the oil level full and using lighter oil the problem is less severe. Also, oil filters that have a good anti-drainback valve will help too. As for rocker arms with bronze bushings, they are a very good investment. :bglasses:
     

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