Oil Thermostat

[Geico266]

I have a question about engine oil temps and oil cooling in my RV9A. I might be over analyzing (more than likely the case) but with the wildly varying airtemps here this winter I'm having a heck of a time finding the right combination. I would like the oil temps to be 180F. When I block off the oil cooler I get temps up to 230F (not good) and when I don't I get temps 140F (with lots of condensation on the dip stick.) I then read about a VERNI-THERM VALVE that can be installed as an oil thermostat? I have an I0-360 with the oil filter coming out the back of the engine (no remote).

Does anyone have any experience with this oil thermostat? Can I install one? Do I need to add the remote oil filter set up? Are there any instructions / info?

Any help would be appreciated, I'm really new to Lycoming.

[Mel]

The Verna-therm should be standard on all engines with the Lycoming oil filter.
Look at the bottom side of the oil filter adapter and look for a large hex nut.
I've had luck by installing an oil cooler block-off plate, and drill holes, making them bigger untill I get the desired temps. I personally like to see oil temps around 200 degrees.

[Geico266]

Thanks Mel, I have been doing some more research and I see what you are talking about.

If the valve is installed and working properly why would my oil temps only be 140F? Maybe I wasn't in the air long enough?

[Geico266]

Originally Posted by Mel

I've had luck by installing an oil cooler block-off plate, and drill holes, making them bigger untill I get the desired temps. I personally like to see oil temps around 200 degrees.

If the thermostat works properly why would we need to block the oil cooler?

I agree with the temps around 200F to get rid of water condensing in the oil system. In my Rotax ultralight days I designed an inflight adjustable valve to allow oil to circulate through the cooler or not. Rotax recommends 215F once a day to get rid of water, then 180F for normal flights. My bypass valve worked great.

[David-aviator]

Originally Posted by Geico266

If the thermostat works properly why would we need to block the oil cooler?

I agree with the temps around 200F to get rid of water condensing in the oil system. In my Rotax ultralight days I designed an inflight adjustable valve to allow oil to circulate through the cooler or not. Rotax recommen ds 215F once a day to get rid of water, then 180F for normal flights. My bypass valve worked great.

The device is not a thermostat. It's only function is to force oil through a cooler when the oil is hot. In cold weather, oil flow is through the cooler or back into the engine, like a plumbing Y. Flow through the cooler is never blocked even if the device fails. When it closes, it closes the port to the engine (not the cooler) and oil must flow through the cooler.

Most certified aircraft with Lycoming engines have a winter cooler kit for this reason. Air flow across the cooler must be blocked to provide for adequate oil temperature.

When I flew with Lycoming, I blocked the cooler with a piece of aluminum with enough .5" holes to cause the oil temp to run at about 200 degress. It will vary with OAT.

[Geico266]

Originally Posted by David-aviator

When I flew with Lycoming, I blocked the cooler with a piece of aluminum with enough .5" holes to cause the oil temp to run at about 200 degress. It will vary with OAT.

That is the problem. OAT has been anywhere from 15 - 50F. Been a crazy winter with no end in sight. I have to pull the cowling everytime to get at the oil cooler. Just a PITA.

Would one of these work?
http://www.xse.com/leres/ss/images/mocal-ot2-sm.html

[Mel]

First thing I would do is check the calibration of your oil temp gauge. It's unusual for oil temps to run that cool in an RV. Usually oil cooler block-off plates are only required in cold OATs.

[Rick_Luck]

I've got an 0-320 in my RV-9A with a Positech 4211 oil cooler installed. From what I've experienced and read on this forum, that combination will give you cool oil temps, even in the summer. In the past, I blocked off my oil cooler. First by trying to block off the back side of it (that seemed easiest at the time) but had little efffect, then trying the front side (worked better but not completely cured) and finally, blocking both the front and back sides for the winter.

Last spring I drilled a few holes in the front block-off plate before a trip to Denver, when I thought I might experience some warm temps out there. That worked for that trip, but what I hope will be the best solution is the Van's adjustable shutter I just had installed when the annual was being done a few weeks ago. Now I can open and close the front block-off plate from inside the cockpit. Unfortunately, when the mechanic installed the front shutter, he removed the rear block-off plate so I'm back to an adjustable front plate only. On the first trial, I got oil temps around 170 F when the outside temps were about 35 - 40 F, which leads me to believe that I might have to re-install the rear block-off plate for the winter. I think even with the rear plate installed and the front shutter open, I could still travel anywhere in the southern tier of the US in January without the oil temps overheating. Instead of re-installing the rear oil cooler blank-off plate though, my mechanic wants me to try installing some cowl flap block off plates between the exhaust pipes to try to reduce the airflow through the cowling, and thus increase CHT's and oil temps and also be "ramp" removable or installable without the hassle of removing my cowling. Has anyone tried that approach?

Rick Luck
Duluth, MN
N109RV
RV9A

[David-aviator]

Originally Posted by Geico266

That is the problem. OAT has been anywhere from 15 - 50F. Been a crazy winter with no end in sight. I have to pull the cowling everytime to get at the oil cooler. Just a PITA.

Would one of these work?
http://www.xse.com/leres/ss/images/mocal-ot2-sm.html

Don't know if it work or not. The Lycoming design as is, is fail safe. If a true thermostat is used as with liquid cooling, a failure in the closed position will cause no oil cooling at all. That is a definite down side.

I have seen a slider device over the cooler. That would be a safer route to go. It would take a push-pull throttle type cable to regulate the air flow across the cooler.

It is PITA with the aft mounted cooler. It is not the end of the world if oil temp does not get up to 190 on every flight, but certainly we need to get it up now and then to cook out any moisture in the system.

The Subaru oil temp barely gets up to 160 this time of year, so we have the problem also. Fortunately, the cooler is up front and it is no big deal to block off part of the cooler with 500 mph tape.

[Jim Percy]

Might consider one of these:

http://www.vansaircraft.com/cgi-bin/...ct=oil_shutter

I don't have one or know anyone that does, but it seems like it might be just the thing for your issue.

Jim