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Technical Why do these fans click and snap?

Discussion in 'The Hokey Ass Message Board' started by oldrelics, Oct 13, 2018 at 9:26 PM.

  1. oldrelics
    Joined: Apr 7, 2008
    Posts: 1,728

    oldrelics
    Member
    from Calgary

    7ECD3A62-9719-4EFB-8E8C-9536CD42B637.jpeg CA65CBB2-DD1F-409C-A8D6-CD8DF4DDF51D.jpeg I love this fan, its large and does a great job of cooling my sbc, but at low idle it clicks and snaps, which is super annoying.
    I tried another that is a 5 blade and same style, but it does the same thing!
     
  2. BamaMav
    Joined: Jun 19, 2011
    Posts: 2,218

    BamaMav
    Member
    from Berry, AL

    Sounds to me like it might have a loose blade. I had that exact same fan on my 350 and it never made any strange noises. You might want to look at it closely before it loses a blade.
     
    seb fontana likes this.
  3. Mr48chev
    Joined: Dec 28, 2007
    Posts: 23,351

    Mr48chev
    ALLIANCE MEMBER

    Check real close for cracks too. I've had a couple crack on me. They do pull air though. Had on on my 71 GMC that would just about pull you though the radiator.
     
    tractorguy likes this.
  4. BJR
    Joined: Mar 11, 2005
    Posts: 4,532

    BJR
    Member
    from Minnesota

    Loose rivet?
     
    ClayMart likes this.
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  5. 4wd1936
    Joined: Mar 16, 2009
    Posts: 600

    4wd1936
    Member
    from NY

    If you are sure it is the fan making the noise please remove it and chop it up so no one else can use it. A very good friend was killed a few years ago by one of those when it came apart.
     
    49ratfink and tractorguy like this.
  6. Deuces
    Joined: Nov 3, 2009
    Posts: 15,040

    Deuces
    Member
    from Michigan

    I'd buy a clutch fan....
     
  7. rockable
    Joined: Dec 21, 2009
    Posts: 2,143

    rockable
    Member

    Do you have AC? Those fans are flexible. The AC compressor on my SBC caused the idle speed to "lope". As it did, it sort of whipped the fan and made it hit something that was in the near vicinity on my old 54.
     
  8. Work In Progress
    Joined: Dec 14, 2010
    Posts: 113

    Work In Progress
    Member

    [​IMG]

    I was lucky, came out the bottom with no damage or death. Check your fans carefully.
     
    dana barlow and tractorguy like this.
  9. belair
    Joined: Jul 10, 2006
    Posts: 7,497

    belair
    Member
    1. H.A.M.B. Chapel

  10. Expansion and contraction within the laminated stiffener to blade/blades.
     
    bobss396 likes this.
  11. I suppose you could try re-staking the rivets, but some of them are going to be hard to get at to support them properly. How long of a fan spacer are you using? Check that for cracks as well. Maybe the fan itself could be magnafluxed.

    Maybe try running another fan blade just to make sure it's not the pulley or water pump making the noise.
     
    olscrounger likes this.
  12. I always prefer to run a steel blade fan and this 17" fan from summit is what I have on the Deuce sedan & on the Ranch Wagon, no problems and they move a lot of air. HRP

    [​IMG]
     
    olscrounger likes this.
  13. finn
    Joined: Jan 25, 2006
    Posts: 505

    finn
    Member

    I remember Ford having a recall on fans like that, probably thirty years ago. The blades let go and killed a few mechanics reving the engine with the hood open.
     
  14. oldrelics
    Joined: Apr 7, 2008
    Posts: 1,728

    oldrelics
    Member
    from Calgary

    Why would that fan come apart there? There isnt even a joint there?



     
    scrap metal 48 likes this.
  15. Ebbsspeed
    Joined: Nov 11, 2005
    Posts: 4,276

    Ebbsspeed
    ALLIANCE MEMBER

    It probably had some slight damage at one point, or was maybe just plain defective from the factory. Maybe a tiny crack in the stiffening rib, and the cyclical flexing of the blade due to changes in RPM caused it to expand that crack until centrifugal force overcame the integrity of the uncracked portion. Id like to see a close-up side view of that break immediately after the blade separated. It would likely tell the story. But the photo is six and a half years old so that forensic evidence is probably no longer visible.
     
  16. 302GMC
    Joined: Dec 15, 2005
    Posts: 5,083

    302GMC
    Member
    from Idaho

    ^^^^^^^
    Vibration cracked ...
     
  17. Gman0046
    Joined: Jul 24, 2005
    Posts: 5,047

    Gman0046
    Member

    I'd replace it ASAP before it causes some real damage.
     
  18. oldrelics
    Joined: Apr 7, 2008
    Posts: 1,728

    oldrelics
    Member
    from Calgary

    I just changed it to a 19” like the broken one pictured above.
    I didnt find anything visually wrong with the other two.
    They came off of 80’s chevy trucks, ive never heard others having problems with them.
     
  19. Work In Progress
    Joined: Dec 14, 2010
    Posts: 113

    Work In Progress
    Member

    After closer inspection it clearly started at one of the rivets, there was a small amount of rust in a section of the crack near the suspect rivet. None of them were loose though.

    Adam


    Sent from my iPhone using H.A.M.B.
     
  20. Work In Progress
    Joined: Dec 14, 2010
    Posts: 113

    Work In Progress
    Member

    Here you go. This thing let go at about 4000 rpm getting on the freeway. It made such a noise and of course vibration I thought my little flathead let go. I went back to get the piece and that’s all I have now.
    [​IMG][​IMG][​IMG][​IMG]


    Sent from my iPhone using H.A.M.B.
     
  21. Jack E/NJ
    Joined: Mar 5, 2011
    Posts: 468

    Jack E/NJ
    Member
    from NJ

    Looks pretty jagged and would hurt if it hit you. Think I'll use non-trad plastic electrics afterall or a heavy steel shroud. Jack E/NJ
     
  22. Work In Progress
    Joined: Dec 14, 2010
    Posts: 113

    Work In Progress
    Member

    I agree ^^^^^^^^
    Either a new mechanical fan or electric, no more old fans. I had just finished a tune up and was test driving it when it let go. 10 minutes prior I was right next to it with a timing light.

    Adam


    Sent from my iPhone using H.A.M.B.
     
  23. 49ratfink
    Joined: Feb 8, 2004
    Posts: 16,737

    49ratfink
    Member
    from California

    I never stand in line with anything that spins like that... fans, cut off wheels, bench grinders etc. had a grinding wheel on my bench grinder explode on startup. put a nice dent in the wood paneling I had in the garage at the time.. could just as easily have been my face.
     
    trollst likes this.
  24. 49ratfink
    Joined: Feb 8, 2004
    Posts: 16,737

    49ratfink
    Member
    from California

    ""I tried another that is a 5 blade and same style, but it does the same thing!""

    if two fans make the same noise there is a good possibility it is not the fan at all.
     
  25. Ebbsspeed
    Joined: Nov 11, 2005
    Posts: 4,276

    Ebbsspeed
    ALLIANCE MEMBER

    Were these pictures taken recently, or right after the fan broke? Parts of the break show rust on the crack, and other parts look shiny. It looks like the crack may have started right at a rivet hole.
     
  26. Deuces
    Joined: Nov 3, 2009
    Posts: 15,040

    Deuces
    Member
    from Michigan

    Did I mention to buy a clutch fan????......
     
    egads likes this.
  27. Work In Progress
    Joined: Dec 14, 2010
    Posts: 113

    Work In Progress
    Member

    About an hour ago, 6 years after the break. Yes, it appeared to start at a rivet hole.


    Sent from my iPhone using H.A.M.B.
     
  28. oldrelics
    Joined: Apr 7, 2008
    Posts: 1,728

    oldrelics
    Member
    from Calgary

    no room
     
  29. oldrelics
    Joined: Apr 7, 2008
    Posts: 1,728

    oldrelics
    Member
    from Calgary

    the third non-flex is fine, no noise
     
  30. HemiTCoupe
    Joined: Apr 4, 2013
    Posts: 143

    HemiTCoupe
    Member
    from TN.

    I had the same fan as "work in progress" had on my '65 impala, back in '72 (stock car) I was getting on to a highway, and I heard a load noise, and then a vibration. My fan had thrown a blade, and it stuck into the lower tank. I wiggled it out. The tank never leaked either. So it doesn't need to be a old one. Mine broke the same way.

    Pat
     

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