Mailing List flyrotary@lancaironline.net Message #11253
From: Russell Duffy <13brv3@bellsouth.net>
Subject: oil viscosity?
Date: Wed, 8 Sep 2004 10:29:25 -0500
To: 'Rotary motors in aircraft' <flyrotary@lancaironline.net>
Message
Greetings again,
 
For my next question, what weight of oil are you using?  I'm using Mobil 1 SuperSyn, and have only used 15W-50 so far.  I don't know about the RX-8, but I know that almost every vehicle on the planet uses 5W-30 now.   I bought some 5W-30 the other day, but still haven't decided if I'll use it, or swap it for one of the other weights. 
 
 
My thinking when picking up the 5W-30 was to limit the resistance through the cooler, and filter.  I also understand that lower viscosity oil will probably provide better cooling, due to higher flow, and perhaps better heat transfer.  It would also limit the initial pressures that will be seen on a cold startup.  Bruce did mention that he thinks Tracy prefers the higher weight oils for the benefit of the redrive, since it's using engine oil, rather than the proper gear lube.  Of course, these are auto transmission gears, which don't use heavy lube anyway.   
 
SuperSyn comes in 5W-30, 10W-30, and 15W-50, so which would be best?
 
Thanks,
Rusty (drinking low viscosity coffee)
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