Now that the weather is hot I'm seeing my oil temps creep over 200 again in cruise. My 8A was born and raised in Minnesota and I only had to deal with oil temps over 200 a couple of days per year. I'm in North Carolina now and would like to see a few degrees cooler stabilized oil temps.
I'm due an oil change and wondering if anybody has seen any temperature drop from changing to a semi-synthetic like Exxon Elite. I'm using Phillips 20w50 now.
Thanks
Paul Danclovic
Jamestown NC
RV-8A N181SB
What are your actual temps and what is the OAT at the surface when you see those temps?
I chased oil temperatures for about the first year I flew my RV-6. I made numerous minor modifications until I found one that worked (bigger baffle opening for air into the cooler), and talked to a bunch of experts - Lycoming, Van's, Pacific Oil Coolers, Skyranch Engineering, Don George, etc. Based on data from those sources, the ideal oil temperature is ~190 +/- 10F. But you're likely to have a hard time maintaining that on a 90 or 100F day.
My experience was that switching to a semi-synthetic didn't move my oil temperatures enough to notice. In theory, there should be slightly less friction when running the semi-synthetics, but friction is a very small component of the heat generated by a Lycoming.
My $0.02 worth is that if you're seeing temperatures of slightly greater than 200F on >85F days, no immediate action is needed. If you see temps >215 during cruise, you're getting to a point where it is probably time to try and bring the temps down.
A couple of suggestions would be cylinder blockers to reduce the cooling air consumed if cylinders on #1 or #2 are cooler than #3 and #4. Also, if your cooler is baffle mounted, a slight increase in the size of the baffle opening might be beneficial. It was for me.