[SPAM] Re: [SPAM] Re: A Bearing Tip - Boca Bearing Newsletter

[David Lockhart]

Keith,

Yup - you got it.  Many compromises with engine tuning.  All other things equal, reducing the compression will require a hotter plug.

Dave
  ----- Original Message ----- 
  From: Keith Black 
  To: discussion at nsrca.org 
  Sent: Sunday, May 22, 2005 1:19 PM
  Subject: Re: [SPAM] Re: [SPAM] Re: A Bearing Tip - Boca Bearing Newsletter


  Dave, I'm not exactly clear on your last message. Are you saying that *with* the head shim plugs go out more easily? This doesn't seem like a good thing, which is why I'm not sure I understand you correctly.

  BTW, what did you use for a head shim? I have the 1.45 and it does not have a head shim.

  Thanks,
  Keith
    ----- Original Message ----- 
    From: DaveL322 at comcast.net 
    To: discussion at nsrca.org 
    Sent: Friday, May 20, 2005 8:55 AM
    Subject: [SPAM] Re: [SPAM] Re: A Bearing Tip - Boca Bearing Newsletter


    Yes.

    Headshims to reduce compression.  Obviously, this reduces the power.  Not as obviously it tends to reduce the amount of unload and it made the engine more sensitive to having a fresh hot plug (engine ran cooler and the plug would go out more easily if set too rich).

    Dave

      -------------- Original message -------------- 

      Dave, did you do something to reduce the compression/timing such as adding a shim to the Webra 160?
        ----- Original Message ----- 
        From: David Lockhart 
        To: discussion at nsrca.org 
        Sent: Thursday, May 19, 2005 11:04 PM
        Subject: Re: [SPAM] Re: A Bearing Tip - Boca Bearing Newsletter


        With specific reference to the OS140, I gotta agree - use the sealed SS BB with both seals.  I've seen 500+ flights.

        I'm also concluding that much of the damage to rear bearings is from running the engines overcompressed resulting in pre-ignition (detonation, pinging, etc).  I just changed the stock bearing in a Webra160 after about 400 flights - all with the compression substantially reduced.  Several years ago, a Bully (Webra) 145 I ran needed new bearings every 100-150 flights, and was relatively much more compressed.

        Dave

          ----- Original Message ----- 
          From: Verne Koester 
          To: discussion at nsrca.org 
          Sent: Thursday, May 19, 2005 11:18 PM
          Subject: Re: [SPAM] Re: A Bearing Tip - Boca Bearing Newsletter


          Rodney, 
          If you're putting it in an O.S. 1.4, definitely leave the seals in. You'll get 300-500 flights with the seals in. With them out, you'll be lucky to put 5 gallons  through the engine before they're shot!

          Verne Koester
            ----- Original Message ----- 
            From: Rodney Tanner 
            To: discussion at nsrca.org 
            Sent: Thursday, May 19, 2005 10:33 PM
            Subject: [SPAM] Re: A Bearing Tip - Boca Bearing Newsletter


            Bob, So using an OS 140 EFI bearing, is it advisable to remove the seals?
            Rodney

            Bob Pastorello <rcaerobob at cox.net> wrote:
              Since I use theirs, I get this e-newsletter.  This month's tip;
              <<If your Front engine bearing has two rubber seals you should not remove them. These bearings have their own grease and can help stop oil leaks. If your bearing has two shields, we recommend you remove one of them. For instructions on removing your shields take a look at this Help Section.

              Your Rear engine bearing should be open on both sides to allow as much fuel as possible to pass through and act as a lubricant. You may however want leave one shield on in the rear which would help to protect the rest of the engine from any foreign matter getting through. This should not be done with one seal. If you find your engine is stingy in getting fuel to the rear, you should definitely leave the bearing open.
              In our next issue of the Boca Bearings Tips & Advice Newsletter we will show you how to remove your bearing shields. >>

              Note - if you open your crankcase, using sealed bearings, and the crankshaft counterweight it dry-looking, or the lower part of the bearing isn't pooling oil, you may think about removing the seals.  I do, for this reason.


              Bob Pastorello
              www.rcaerobats.net
              rcaerobob at cox.net
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