<VV> Corvair Crankshafts

[Smitty Smith]

    Smitty,
        The little knobs on the ends of the crankpins are in fact Counter-weights. They are there for 3 reasons. First: they are there to act as a counter-weight for the opposing cylinder. Second: They help re-focus the vibrations caused by the cylinder firing. Third: to aid in the crankshafts rotation. 
      The Continental Aircraft engine has NO webbing at all on the throws between the crankpins. That is why it vibrates like a washing machine. It does not have the RPM range of the Corvair engine. The Continental Red-lines at 4250 rpms and that is it. I have had Corvair engines turning better than 7,000 rpms all day long with NO affects. The only reason they do no come apart is those little bumps of metal on the ends of the crankpins. 
     If you were to draw a line from the top of the bump to the top of the opposite bump in an X pattern, where the 2 lines intersected would be the direct CENTER of mass of the crank. That is why you see Drilled holes near or on those little bumps. They took metal out to help balance the crank. I have taken metal off and welded metal back in to help balance crankshafts. 
      I have had cranks that I have had to take off as much as 2 lbs of metal to get them to balance out right. All of it off those little bumps on the crank throws between the crank pins. 
      YES the Corvair engine does have counter-weights, they just do not look like a conventional V or other in-line cranks. I could go into all kinds of Physics about as to why the Corvair crank looks and acts the way it does, but would it really matter? It WORKS and is one of the best engines to ever come out of Detroit. 
  Dennis S.   
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  Smitty Says:  unless we can get Dr Benzinger to join in on this conversation we are going to disagree.  Those knobs as you call them are on there strictly to provide a place to remove material for the purpose of balancing the crank.  Counter weights are added to cranks to counter a known weight on the oposite side. 
  I say this knowing I am being "word" picky.  Re: your comment on the "knobs being there to counterweight the oposing cylinder.  There are none around the #3 and # 4 crank throws.  Finally I want you to know you are one smart cookie.  You recognize the engine as being one of the best ever built.                    Smitty