----- Original Message -----

From: Ken Welter

To: Rotary motors in aircraft

Sent: Thursday, October 28, 2004 7:07 PM

Subject: [FlyRotary] Re: Oil Thermostat??

   I tried plugging the bypass once and it dropped the oil pressure to about 30 lbs do to restriction, it seems that there is always some oil passing through the bypass.

  Ken

Ed,

I believe that the only purpose of the oil thermostat in the cooler is for emissions.

It allows the engine to heat up to operating temperature more quickly by by-passing the cooler. If you were to permanently plug the by-pass hole in the cooler the only difference would be the time it takes to get the engine up to running temp. Now if you had a cowl flap on the oil cooler then the thermostat would be redundant as you could control the oil temp with the cowl flap. Just a thought.

Jim

Ed Anderson <eanderson@carolina.rr.com> wrote:

When I drained my oil in preparation for the flight to the Rotary Flyin, I decided to do it a bit different.  My oil cooler is the lowest point in the system and I decided that since the oil thermostat housing was on the bottom of the cooler that draining it from there would be the smart thing to do.

 

So I proceeded to unscrew the plug - but, it wasn't until everything shot into the oil bucket that I realized that the innards had a strong spring incorporated.  So SPLASH! everything into the oil bucket - not problem I fish out the components and then realize that the thermostat pellet will fit either way.  Of course, I did not have my Mazda engine manual since it was only a simply oil change.

 

In my minds eye I recall seeing the spring hit the bottom of the bucket before I heard the heavy "Clunk" of the thermostat hit.  So I finally decided that the spring must have come out of the housing first(forgetting that light travels faster than sound).  After all I had a 50/50 chance of being correct. 

 

So I replaced the thermostat back in the housing and screwed the plug on.  Fired up the engine - and noticed that while oil pressure was fine - the oil temperature did not budge off the bottom of the gauge even after a couple of minutes of running but that the coolant was already up to 120F.  Hummmm.

 

Decided not to put the cowling back on until after going home and consulting a manual.  Sure enough I had installed it backwards.

 

So went back out to day reverse the thermostat and oil temps once more responding normally.

 

This got me to thinking that I fly without a coolant thermostat and wondering whether oil temps would lower if the thermostat was removed or wedge permanently closed.  I know you can not just remove it or the oil will by-pass the cooler.

 

 

My question to those (Lynn?) who have more experience is what effect would removing the oil thermostat on oil temperature??

 

 

Ed Anderson
Rv-6A N494BW Rotary Powered
Matthews, NC
eanderson@carolina.rr.com