Engine or Alternator Sound NAFF

Discussion in 'Mech Tech' started by AndyBcountry, Jul 2, 2020.



  1. Rebuilt the Weber ICT34 - new fuel pump. I haven't tuned yet just got it running and it doesn't sound right - any knowledgable ears recognise a problem? Checked carb bolts, fuel bolts all seem ok.

    Thanks
     
  2. davidoft

    davidoft Sponsor

    Take the alternator belt of and run it, sounds like the fan hitting the tin
     
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  3. OK - will do thanks davidoft
     
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  4. Before you take the belt off, check the “breast tin” - the small piece of tinware on the engine that sits behind the crank pulley. These are easy to bend, and can make a real racket if they’re touching the back of the pulley. Try pushing it in with your thumbs while the engine’s running.
     
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  5. Just checked all clear. Any chance the alternator is knackered - not sure how worn bearings sound?

    Cheers
     
  6. Next step as above - take the fan belt off. That'll determine whether it's the fan or alt.

    The front alt bearings can wear, due to the load of the fan belt.
     
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  7. Makes sense ok thanks will do
     
  8. Did you look into the rear of the pulley, there are two flaps on the fin that extend into there. It sounds scratchy tin to me.
     
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  9. It sounds like its in time with the engine turning so its more likely to be the tinware. Or a bolt lying under the pulley..

    If it was the fan it would be faster and would beat with the engine noises because it is spun faster.
     
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  10. GARRICK CLARK

    GARRICK CLARK Sponsor

    Take fan belt off and see if noise is still there when you run it
    It also doesn't sound like its idling on 4 cylinders
     
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  11. Yes, I can't see anything obvious and I had a good look.
     
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  12. .... funnily enough..... the HT was connected to cylinder 3..... Someone must have put it there when I wasn't looking....
     
  13. Any tips to remove the nut securing the fan belt. Managed to lock off pulley but it is not shifting at all.....
     
  14. Have a listen around the carb with a hosepipe to your ear, after all, it's the carb you've changed. So the odds have it, that it's new addition to the mix causing your problem. Listen out around the spindle, in particular.

    I have a whistling Weber on the Bug, well it's more of a chuffing noise timed to the cam.
     
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  15. Impact wrench, if you've got one?
     
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  16. Or as you don't have 3 hands, forget the one jamming it and use a ring spanner and hammer to shock it round. Works and the jamming thing is more for tightening.
     
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  17. GARRICK CLARK

    GARRICK CLARK Sponsor

    Did you fit the washers to the manifold so not to loose them .... then fit the manifolds back on the heads with the washers still there
     
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  18. While squeezing the belt together...
     
  19. With your third hand.
     
  20. You haven’t got one?
     

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