Randy,

 

Oh, I forgot.  I also replaced the Vernatherm, but I don't remember technical details of the testing (a long story involving a flash fire - best told in a bar).  I believe the chamber that the Vernatherm operates in is such that, when cold, allows oil to bypass being sent to the cooler.  When hot, the extension of the device shuts the bypass opening.  Thus, if the Vernatherm does not fully extend when hot, the bypass is not sealed and uncooled oil would be returned to the system.

 

Here is one example of test results:  http://www.vansairforce.com/community/showthread.php?t=32763

 

Here is some interesting info, click on tech data: http://www.rostravernatherm.com/oil-valves.htm

 

Here is a more interesting read: http://www.sacskyranch.com/eng18.htm

 

Scott.

 

Scott, I was thinking the same thing and am making plans to "redo" my oil cooler to cowl connection and make it nice and smooth. That will happen after I verify the vernatherm is doing what is supposed to... I pulled out the vernatherm the other day and put it in boiling water to see what it would do. I admit I really do not understand how it works but the spring loaded end got about 1/8" longer when going from room temp to 212 F. Does that mean it is working? If anyone knows if this is good or bad, please pipe in... Thanks for the feedback! Randy Snarr --- On Tue, 3/10/09, Sky2high@aol.com <Sky2high@aol.com> wrote: From: Sky2high@aol.com <Sky2high@aol.com> Subject: [LML] Re: oil cooling To: lml@lancaironline.net Date: Tuesday, March 10, 2009, 8:36 PM Randy,   My large sharp edged NACA duct is poorly placed on the left rearward side of cowling.  It enters a short flexible 3" smooth rubber sleeve (plumber's sleeve) and then to a plenum above the small SW oil cooler mounted to the fire wall.  The bottom is open to the lower cowl.  I climb at about 135 KIAS and see cylinders occasional reach 400 degrees on a hot day while the oil stays at 180.  In cruise in 30-40F temps, I must at least partially close the door between the NACA and the cooler.  Recently, in 10C temps, I had to completely close the door to keep the oil temps about 180. In the pattern at 100 KIAS I will see the oil go 190F or even 200F on hot days because of lack of air thru the cooler.    It wasn't always that way.   When I had high oil temps, I tried a special cooler air exit to assist, no help.. Another was to try exiting thru shark gills on the side of the cowl, no help. I temporarily attached a scoop to force more air in the duct, no help.   I finally discovered that the air was backed up in the NACA duct plenum (or chamber), thus cutting off air flow.  I used Micro to smoothly shape the chamber, thus directing the air into its 3" outlet (no more dead corners) with the results detailed above.   Good Luck,   Scott Krueger AKA Grayhawk Lancair N92EX IO320 SB 89/96 Aurora, IL (KARR) In a message dated 3/9/2009 12:41:32 P.M. Central Daylight Time, marv@lancair.net writes: Posted for randy snarr <randylsnarr@yahoo.com>:  All,  Thanks for the good suggestions on the oil cooler.  I flew again today and my oil temps are at 208 F flying in 35 f air.  They will be 215 or 220 this summer.  I will try a few solutions that do not need to cut the cowl. I will most likely make a duct to carry the exhaust air from the oil cooler down to the lower aft part of the cowl. I have also heard that the aft vertical edge of the naca opening should be shaped like an air foil. Mine is flat and fairly sharp. The easiest way to test will to be construct a piece to give it a little airfoil made from balsa or foam taped in place and flight tested. If that does not work, I will make a duct from the cooler to the low pressure area on the bottom of the cowl and lastly would be a small lip on the bottom of the cowl aft.  every producton airplane I have seen with an opening on the bottom of the cowl has 45 deg lip to create a low pressure area. I should have done that before I painted....      I will post my findings when I get them.    Randy Snarr  N694RS   -- SFor archives and unsub http://mail.lancaironline.net:81/lists/lml/List.html   A Good Credit Score is 700 or Above. See yours in just 2 easy steps!