[SPAM] OS 1.40 header

[Lance Van Nostrand]

I've had some success with the O-ring setup.  I had one plane with fixed header and the other with O-ring and started with a bad attitude about the O-rings.  I have since switched both to Oring setups.  Once I figured out the secret to getting long life from the O-rings I find the vibration reduction, stress reduction, weight reduction all positives.  I wrote a KF article on this that will probably show up in the next issue but basically you don't want to remove the header from the O-rings until replacement time.  Remove the adapter from the engine just like a fixed header.  Also, stabilize the coupler firmly.  My mintor has had the same O-rings in it since May or June with no leakage.
--Lance

  ----- Original Message ----- 
  From: AtwoodDon at aol.com 
  To: ed_alt at hotmail.com ; discussion at nsrca.org 
  Sent: Saturday, October 08, 2005 8:34 AM
  Subject: Re: [SPAM] OS 1.40 header


  Ed, I observed the same thing about the OS header flange not matching the exhaust port so I ground it out to match the engine but did not observe any improvement in performance.  I have switched to the Macs header because of the O-ring wear issue.  I did like the isolation of the engine from the header by allowing it to pivot on the rings but you always know it is time to change the o-rings when you start getting some blow by.  

  There was some short comment about a better way to support the OS type header and increase the o-ring life (I think it was here on the discussion group) some time back but I can't remember who it was.

  Don

  Don AtwoodIn a message dated 10/7/2005 7:17:39 P.M. Pacific Daylight Time, ed_alt at hotmail.com writes:
    Just wondering what the opinions are re. the best header for the OS 1.40.  I've got the OS version and it's a bit of a nuisance to deal with the O-ring going bad. Also, it really looks like it would result in improved gas flow (more power) if the inlet for the "matched" header was the same size and shape as the exhaust port.  I'm tempted to grind it down to get that match right.  Has anyone done this and does it help?
    Thanks

    Ed 
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