OS BEARINGS

[Bob Pastorello]

Actually, the groove we did in the small bearing OS 61's was in the upper right 'corner' of the crankshaft area in the crankcase, about 1:30 -2:00 o'clock position, and straight back to the bearing face.  A small hole was drilled at an angle from the area where the bearing race was located into the groove.
    Tricky to describe.  Maybe someone can do a better description.  We actually made ours with the sharp edge of a triangle file...the groove was probably 1/32" or so...maybe a little larger.

Bob Pastorello, Oklahoma
NSRCA 199, AMA 46373
rcaerobob at cox.net
www.rcaerobats.net


  ----- Original Message ----- 
  From: Wayne Galligan 
  To: discussion at nsrca.org 
  Sent: Tuesday, August 05, 2003 8:48 AM
  Subject: Re: OS BEARINGS


  Then a grove machined in the bottom of the crankcase up to the opening of the crank inlet would be the place to make this groove...right?   How could one do this with standard shop tools and not ruin his engine?

  Wayne
    ----- Original Message ----- 
    From: Karl G. Mueller 
    To: discussion at nsrca.org 
    Sent: Tuesday, August 05, 2003 8:52 AM
    Subject: Re: OS BEARINGS


    Wayne,

    On the compression stroke the passage in the crank
    for the carb would be opposite to the carb opening and 
    therefore closed.

    Karl.
      ----- Original Message ----- 
      From: Wayne Galligan 
      To: discussion at nsrca.org 
      Sent: Tuesday, August 05, 2003 9:22 AM
      Subject: OS BEARINGS


      If you machined a groove towards the rear bearing you would lose crank pressure or get blow back to the carb opening from the crankcase pressure wouldn't you?

      WG
        ----- Original Message ----- 
        From: Verne Koester 
        To: discussion at nsrca.org 
        Sent: Monday, August 04, 2003 10:39 PM
        Subject: Re: Mintor 140 Bearings


        Bob,
        Interestingly enough, my RX has the groove you describe going forward toward
        the front bearing (which is shielded anyway) but nothing rearward. I
        considered that as a last option if nothing else worked, but haven't needed
        to as yet.

        Since they already have a shielded bearing in the front, I have to assume
        that groove is there to lube the crank journal in the case between the carb
        opening and the front bearing. If that's the case, then why no groove to
        lube the journal between the carb opening and the rear bearing? Friction
        equals heat, right? Maybe they're relying on the heated aluminum case
        expanding enough to allow oil in there but then there'd be no reason for the
        forward groove.

        Verne
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