Webra TruTurn Adapter Bushing Problem (the saga continues)

[Keith Black]

MessageWell, I took my Webra and bushing by Gray "I'll make it fit" Fowler's house this evening and he changed his mind about trying to grind the bushing to make it fit. He has a Bully that has an unusually wide crank shaft and my bushing still fit easily over his crank shaft. It seems that I'm the lucky "one in a hundred" Webra owners that has an unusually large crank shaft. 

Honestly at this point I'm not sure if it is wider, out of round, the threads are sifted to the side, or what. 

One thing that I did notice was the hole in the end of the crank shaft is slightly off center, but I'm not sure if this has anything to do with the bushing not fitting. See attached link for picture: http://www.fototime.com/69B94D3126C46B6/standard.jpg

Thanks to everyone for you help, especially to James Woodward for offering to test and break-in my engine this season ;-)

Keith
  ----- Original Message ----- 
  From: David Flynt 
  To: discussion at nsrca.org 
  Sent: Wednesday, January 08, 2003 8:15 PM
  Subject: RE: Webra TruTurn Adapter Bushing Problem (more info)


  I just looked at my new 1.45 red head and new TT adapter (TT-0825-A).  The bushing slides down without any resistence. The non-threaded area of the shaft on the Webra is 0.311-0.312 inches in diameter; the ID of the bushing is 0.315 inches.

  David Flynt
    -----Original Message-----
    From: discussion-request at nsrca.org [mailto:discussion-request at nsrca.org]On Behalf Of Keith Black
    Sent: Wednesday, January 08, 2003 1:31 PM
    To: discussion at nsrca.org
    Subject: Re: Webra TruTurn Adapter Bushing Problem (more info)


    I have some more info on the bushing problem. 

    I also have a Bully 1.45 that I bought new at the same time as the Webra. It is on another plane but I've never mounted at TruTurn spinner on it. I just tried the bushing on it and it fits fine, in fact it slides on very easily.

    Looks like the crank on this particular Webra is just a tinny bit larger.

    Lee, I'm sure your suggestion of heating the bushing would work, but Alan brings up a good point about the front bearings. It may be a real chore to get the existing bearings off, though the oven would probably do the trick with those too. 

    I wonder if this will effect the way the engine runs given that the fit on the front bearings may be tighter?

    Keith

      ----- Original Message ----- 
      From: Alan Simmonds 
      To: discussion at nsrca.org 
      Sent: Wednesday, January 08, 2003 2:50 PM
      Subject: RE: Webra TruTurn Adapter Bushing Problem


      Just a thought... if the crank was oversize it would not fit the front bearing.

      Alan Simmonds

       -----Original Message-----
      From: discussion-request at nsrca.org [mailto:discussion-request at nsrca.org] On Behalf Of Lee Davis
      Sent: 08 January 2003 19:10
      To: discussion at nsrca.org
      Subject: Re: Webra TruTurn Adapter Bushing Problem


        This is a new one I haven't heard of before.  If you don't have any luck you can always return the engine to us and we'll check it out.  Look hard at the bushings, though.  It's difficult to imagine that out of all the Webra engines there's one that's oversized at the crank end.  Anything's possible though.

        One likely solution just occured to me.  Try heating the bushing in the oven or with a small torch.  The aluminum will expand quite a bit and I'll bet it will then slip over the crank.  It's probably not off more than a couple of thousandths.

        Lee Davis
        Piedmont Models
        http://www.piedmontmodels.com/
          ----- Original Message ----- 
          From: Keith Black 
          To: discussion at nsrca.org 
          Sent: Wednesday, January 08, 2003 12:56 AM
          Subject: Help: Webra TruTurn Adapter Bushing Problem


          I have a new Webra 1.45 Aero X and I'm trying to mount a 3 1/4" TruTurn FAI spinner on it. The adapter kit that is listed for this engine on both TruTurn's and Piedmont's web page is TT-0825-A which contains an 8mm bushing. 

          The bushing fits over the threaded part of the crankshaft, but will not fit over the unthreaded base of the crankshaft. 

          I tried another 8mm bushing that I have to make sure that the bushing with the adapter kit wasn't incorrect and neither bushing will fit. 

          Using a caliper the base of the crankshaft measures about 8.1 to 8.2 mm.

          Has anyone else had this problem? Any suggested solutions?

          Thanks,
          Keith Black



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