Crankshaft balancing.... again

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  • Pisobiker
    S2Forum Extremist
    • Jul 2003
    • 1175
    • Country: Finland

    #1

    Crankshaft balancing.... again

    Hi all,
    I've actually finished building my own equipment for crankshaft balancing but now another problem arose.
    I was thinking to balance the whole crankshaft+flywheel+beltpulley assembly and while inspecting the pulley (harmonic balancer) on a lathe I noticed it actually wasn't turning perfectly centered. I then disassembled it and verifyed belts shell turns quite straight, while the balancer has a small "out of axis" rotation.
    Now the problem is (apart form the cost of buying a new one) somebody told me they probably come this way form the factory so I might order a new part while getting exactly the same I already have.
    Anybody any experience with this?

    Thanks

    Marco
  • SteveH
    Super Moderator
    • Jul 2003
    • 4460
    • Country: United Kingdom

    #2
    Marco,

    I had something similar when the balancing company attempted to balance my crank. In my case, it was a problem caused when the harmonic pulley had become loose over time. Due to the pulley being heavier on one side, it had hammered the nose of the crank and damaged both the crank pulley and the crank end. Both were machined and they were able to continue with the balancing. This is a fairly common problem with the 5cyl
    Your problem could be due to the rubber in the harmonic balancer having become damaged over time. I'd guess a new pulley would cure it.
    91 Modded 3B
    14 A6 Avant Black Edition

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    • Doug_RS2
      S2Forum Possessed
      • Jul 2003
      • 3847
      • Home: Scotland Current: England

      #3
      I think mine has a wobble as well - what exactly did they machine to get it balanced properly Steve?
      S2,RS2,S4 WB,RS4,S4 B8,RS6 C5,RS6 C6,R8

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      • Pisobiker
        S2Forum Extremist
        • Jul 2003
        • 1175
        • Country: Finland

        #4
        Thanks Steve for the answer.
        Unfortunatly the pulley isn't exactly a cheap replacement and my concern was about getting a new pulley that is nothing better then the one I already have spare.....

        I will try to see the balancing of all the conponents trying to figure out why the single parts cannot be balanced by themselves (i mean crank+bobweights, flywheel and pulley).


        Marco

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        • SteveH
          Super Moderator
          • Jul 2003
          • 4460
          • Country: United Kingdom

          #5
          Originally posted by Doug_RS2
          I think mine has a wobble as well - what exactly did they machine to get it balanced properly Steve?
          Doug,

          I had the end of the crank and the harmonic balance pulley machined to get them back to 90 degrees. The crank isn't the easiest item to machine though, due to it's shape and size. It all runs true since it was done. I've been really happy with the work that was done.
          91 Modded 3B
          14 A6 Avant Black Edition

          Comment

          • Pisobiker
            S2Forum Extremist
            • Jul 2003
            • 1175
            • Country: Finland

            #6
            Steve, how much did the balancing work cost?

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