REFLECTOR: oil temp problems solved

[Jack Sheehan]

Tom,
Just for info I developed a slight increase in oil temps after about 
600 hours of flying. I spent a lot of time looking at the problem oil 
changed, checked screen, new filter, oill sammple etc. Filally took 
the vernaterm out and checked it , cleaned it checked it for 
operaionn (expansion in hot oil) everything looked good. Flew it 
again still the oil temp was high ( 214 degrees) normal was always 
200. I replaced the vernatherm just because I was out of ideas. Still 
no change. I then removed the oil filter housing the vernatherm goes 
into and took it over to the engine shop and they had a tool they 
routinely use to dress up the seat the vernatherm seals against. 
There was no obvious defect the old vernatherm had a 360 degree ring 
around the valve indicating it was seating ( or had been). The result 
of the dressing of the seat fixed the problem and infact has the temp 
down to 198 as normal.
I do have a rear cooler which is a big help but my real use of the 
rear cooler is that I draw air thru a seperate scoop under the wing 
and have a 12 volt (marine) blower in line to force air through the 
cooler during ground operations. After landing where I have to taxi a 
long while (Oshkosh , Sunn-N-Fun etc) I can switch the blower on when 
the temps get high (over 220 ) and can watch the temps decrease 
immediately. I would not have thought the dressing up of the 
vernatherm seat could make that difference. Live and learn.

Jack

   At 09:34 AM 4/13/2007, you wrote:
>After several attempts at making the one oil cooler scenario work, I
>gave up and added a 2nd cooler-steady temps dropped from 240 to 195. I
>placed the 2nd cooler on the upper engine baffle (strongly braced). I
>made a 3" tee (45 degree) out of aluminum tubing and share the ram air
>for the induction with the duct for the new cooler. Flew plane this
>morning and the manifold pressure appears to be the same, guess the ram
>air was a bit of overkill in stock configuration. I do believe that the
>vernatherm is the main issue in causing higher temps. The extra plumbing
>intrinsic to the Velocity design increases oil pressure and at cruise
>speed keeps the vernatherm partially open. When you pull power and the
>pressure decreases you can see an immediate drop in temps. Although I
>did install a new vernatherm I've saved the old one to modify for
>testing. While I was at it, I sealed up the baffling and the CHTs
>dropped from 375 to 320. Life is good! Now I can start playing with the
>avionics (after Sun-N-Fun).
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