Mailing List flyrotary@lancaironline.net Message #13037
From: Russell Duffy <13brv3@bellsouth.net>
Subject: RE: [FlyRotary] MMO vs 2-cycle (was Re: how do you carry, and measure oil?)
Date: Sun, 21 Nov 2004 08:39:27 -0600
To: 'Rotary motors in aircraft' <flyrotary@lancaironline.net>
Message
    I have used the MMO/2 cycle mix in the past but for the last 100 hours I have been using the Wal-Mart Marine 2 cycle oil.  After reading up on the different classifications of 2 cycle oil (most brands are all in one now) and looking at the temperature profiles for the apex seals I concluded that almost anything would do a better job than crankcase oil of lubricating the seals.  And 2 cycle certainly leaves less residue than crankcase oil. 
 
Mornin' Ed,
 
Is MMO and 2-cycle oil close to the same thing?  When I try to rationalize using one over the other, I come up with one other issue.  Our pre-mix oil does get scavenged into the crankcase to some extent.  MMO is made to be used in fuel, and oil, so that's not a problem.  I can't say that I've ever heard anyone comment on the effect that 2-cycle oil has in our crankcase.  I've wondered if this alone is a reason to prefer MMO over 2-cycle oil. 
 
Another question just came to me.  Does oil injection cause oil to be scavenged into the crankcase?  I'm assuming it would be less than what we get with pre-mix, though some must make the trek.  I wonder if Mazda considered that when deciding to use crankcase oil for the apex seals?  Of course originally, they weren't using the dripper injectors, but rather injecting the oil into the fuel/air stream at the carb. 
 
Cheers,
Rusty
  
 
 
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