OS Piston Pin

[Verne Koester]

Eric,
Not at all like a lecture. Last night about 10:00, I would've paid good money for it so I could fly today. Between the various responses, I was able to realize what you just explained and got it off. Next comes the rear bearing itself which is locked solidly onto the crank. Came out of the case okay with a little help from my heat gun, but coming off the crank will be another matter. I've been flying YS for so long now that I've forgotten how to get through these little chores.

Thanks,
Verne
  ----- Original Message ----- 
  From: Henderson,Eric 
  To: discussion at nsrca.org 
  Sent: Wednesday, July 02, 2003 9:32 AM
  Subject: RE: OS Piston Pin


  Verne,
            The OS 1.40 requires you to slide the conrod on the wrist-pin. There is enough travel to then allow you to remove the big-end from the main crank pin.

  The problem is that the wrist-pin gets dirty either side of the conrod. This prevents the conrod moving easily. I have had to reach in there with a scraper before now. Most times a strip of cloth with Mineral Spirits can be treaded around the wrist pin and then pulled back and forth to polish the wrist pin in situ. Sometimes I have had to use Acetone as well.

  To remove the rod I hook my pinky around the rod and pull it towards the rear of the engine. It should move about 3/16".  It will then come off with the crank near TDC. With the piston assembly removed I always polish the writ pin for the next time. 

  If you disassemble the piston assembly make sure you orient the rod the same way that it came off. There is a chamfer at the front of the phosphor bronze bearing.

  (Hope this did not sound too much like a lecture?)

  Regards,

  Eric.

    
  -----Original Message-----
  From: discussion-request at nsrca.org [mailto:discussion-request at nsrca.org]On Behalf Of Verne Koester
  Sent: Tuesday, July 01, 2003 11:29 PM
  To: discussion at nsrca.org
  Subject: Re: OS Piston Pin


  Troy,
  Thanks, I'll try it. Never thought it would work after seeing the groove machined into the crankcase for connecting rod clearance.

  Verne
    ----- Original Message ----- 
    From: Troy Newman 
    To: discussion at nsrca.org 
    Sent: Tuesday, July 01, 2003 11:07 PM
    Subject: Re: OS Piston Pin


    Don't have to remove the piston from the wrist pin to get the piston, and con rod out for removal of the crank....Just takes a little patience....Its not like a YS.....it will come apart....Try going to bottom dead center and just slide the con rod back and off the crank pin....Viola its off....Goes back together the same way. Its a little tough but things are sized to allow for the removal of the piston and conrod as a unit. Just like a .46 or the .61's

    Its cake after the first time.

    I doubt you will ever get the wrist pin out of the motor via the exhaust port....But then again other guys have seemed to do some pretty weird stuff with motors....


      ----- Original Message ----- 
      From: Verne Koester 
      To: NSRCA 
      Sent: Tuesday, July 01, 2003 10:56 PM
      Subject: OS Piston Pin


      Anyone know how to get the piston pin out of an OS 1.4RX? Working through the exhaust port, I got the circlip out but the pin seems to be stuck pretty good. I thought I read where the id of the pin was threaded but it doesn't SEEM like it is. Can't see in there real well but the id feels pretty smooth. I want to replace the rear bearing before the Nats to avoid any possible problems.

      Thanks,
      Verne
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