Mailing List flyrotary@lancaironline.net Message #14251
From: Tracy Crook <lors01@msn.com>
Subject: Re: [FlyRotary] Re: Oil cooler mount updated pictures
Date: Tue, 21 Dec 2004 11:59:28 -0500
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Message
I'll go with Rusty's take on this one.  First off, there IS a pressure bypass in the system (the oil pressure regulator).  I see almost no difference in cold oil pressure than I do with hot oil when the engine is turning fast enough to be "in regulation".  The only difference is that the regulation point rpm is lower with cold oil. 
 
The thermostat does not isolate pressure from the oil cooler anyway since it is not an oil tight system.
 
Tracy
Sing that song to your last cooler again, maybe it will believe. Maybe not. (I know, tackie sa comment, I apologize.) Too a certain extent, you are or should be absolutely correct, 5w-30 should be no thicker cold than 5 and no thinner hot than 30, but, why chance it ? It also shouldn't have any more pressure, period, than bypass allows but something obviously causes oil to act differently than water, with coolers anyway; and, while hydraulic pressure is hydraulic pressure, fluid density, compressibility difference, whatever, seems to be a good a guess as any; and, one perhaps easily avoided by thermostatically controlled relief valve.  Why beat the poor little sucker to death waiting for oil to reach 140, if it does have any effect ? 
jofarr
----- Original Message ----- From: Russell Duffy
 
I disagree.  I'm using 5W-30, so when it's cold, cold, cold, the oil still isn't thick, thick, thick :-)  Also, airplane guys are kind to their engines.  We crank them, and allow them to gently warm up before running them hard.  This is very different from how it would be used in the car, which I suspect is why Mazda included the oil thermostat.  The only hassle is waiting for it to get 140 degrees before takeoff.  I see the thermostat as being nice, but not necessary.
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