Geico266

Geico266

Well Known Member
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.
 
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.
 
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?
 
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Mel said:
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.
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If the thermostat works properly why would we need to block the oil cooler? :confused:

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.
 
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Geico266 said:
If the thermostat works properly why would we need to block the oil cooler? :confused:

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.
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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.
 
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David-aviator said:
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.
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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
 
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.
 
regulating oil temps

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
 
Geico266 said:
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
Click to expand...

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.
 
Geico266 said:
.....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.......Any help would be appreciated....
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Initially, I had to experiment a bit and installed a sort of standoff plate behind my baffle mounted oil cooler to help raise the temp past the 170 degrees my new Lycoming engine ran even through the hottest of summer weather. It worked and raised the temp up to the 185 degree range give or take. Later on, I stumbled upon an interesting thing. A locally based 1974 Piper Warrior (certificated) has virtually the exact same set-up fitted to its baffle mounted oil cooler. Both it and another friend's Cherokee have a winterization plate that is bolted to the front of the oil cooler for use in cold temperatures.

There is an alternative. You may want to review this thread.

http://www.vansairforce.com/community/showthread.php?t=4289

Scroll down a bit to review photographs and more information about Van's oil cooler shutter that helps solve a common and vexing problem. The shutter is a simple, lightweight and fascinating piece of clever engineering.
 
I was at a fly B-fast in today in York, NE (KJYR) (The 1st Sat of every month, great made-to-order breakfast meals!) and a couple of guys recommended the Van's baffel too. I just ordered it and I'm gonna install it during the next annual.

Thanks guys & gals. I appreciate the help & support.

Happy & Safe Flying.
 
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Mel said:
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.
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I calibrated the oil temp guage and it is good to within 10 degrees or so at 200F. Close enough for government work. I installed a Vans oil cooler shutter with in cabin adusting cable, and will be going for a test flight today.

Does anyone else have moisture on their dipstick? I'm hoping running the oil temps closer to 200 will get rid of the moisture. Any thoughts?
 
Well, I'm back at the oil thermostat project again. I bought a Rans S-12XL with a Rotax 912S and it has an oil thermostat installed and it works great! I'm thinking seriously of installing one on my 9A.

http://www.perma-cool.com/Catalog/Cat_page14.html

Here is a link to the Perma-Cool website. It fails open, so shutting off oil flow to the cooler is (in theory) not a problem.
 
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Vernatherm not like a auto thermostat...

I must have missed this thread the first time around. The reason that Lycoming's system runs oil through the cooler in parallel with the internal pathway (inside the engine) when the oil is cold, and then only (or mostly) through the cooler when it is hot is the following. If no oil was flowing through the cooler, the oil will gel and get too thick to flow at all in cold weather. The auto cooling system analogy would be if the OAT was below the antifreeze rating - one would want to always have the thermostat open somewhat to keep the coolant moving through the radiator.

Someone posted earlier that temps of 150F for oil were unusually low. In fact, it is quite typical of flying with OAT's in the teens. The only good solution is to put some sort of damper in the airflow to the cooler. You do not want to stop or regulate oil flow through the cooler. To be convinced, put a quart of aviation oil in the freezer overnight and then try to pour it.

When I return from a winter flight, or short summer flight, I always loosen the oil dipstick and prop it up an inch over the filler tube. It is unbelievable how much steam will come up out of the engine during the first ten or twenty minutes. All this steam would instead condense inside the engine.
 
I am confused

If you have a vernatherm which works and the Vans adjustable oil cooler airflow system, are you still having high/low oil temperature problems?
 
Geico266 said:
Well, I'm back at the oil thermostat project again. I bought a Rans S-12XL with a Rotax 912S and it has an oil thermostat installed and it works great! I'm thinking seriously of installing one on my 9A.

http://www.perma-cool.com/Catalog/Cat_page14.html

Here is a link to the Perma-Cool website. It fails open, so shutting off oil flow to the cooler is (in theory) not a problem.
Click to expand...



I have a kitfox with a 912ul 80, I installed one of these two years ago. Before I did this I was blocking off the oil cooler, what a peta, never could get it right, now I just start and go, doesn't matter the temps outside, I maintain 180 plus on temps for the oil. Warms up are much faster as well. I really want to put this on my lyc when the times comes.
 
Perma-cool item

This sounds exactly like what a vernatherm accomplishes. If so why not just use a vernatherm and avoid the extra plumbing lines.

In cool temps, use an engine pre-heater. I use a sump heater by Reiff but there may be other options.
 
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Ron Lee said:
This sounds excacly like what a vernatherm accomplishes. If so why not just use a vernatherm and avoid the extra plumbing lines.

In cool temps, use an engine pre-heater. I use a sump heater by Reiff but there may be other options.
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I have a vernatherm installed in my 0-360. It simply does not work like this thermostat. This would eliminate the need for putting duct tape over the oil cooler, or installing an oil cooler shutter that blocks 50% of the airflow. Having oil temps only reach 140F in the winter is not a good thing for any engine.
 
I plan on an oil sump pre heater as well. This thermo is absolutely amazing. I don't have to do anything, just go fly. This tinkering thing in the cockpit is out, I want to put my attentions on more important things. Like flying.
 
allbee said:
I plan on an oil sump pre heater as well. This thermo is absolutely amazing. I don't have to do anything, just go fly. This tinkering thing in the cockpit is out, I want to put my attentions on more important things. Like flying.
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Steve, what oil do you use in the Kitfox with the oil thermostat?

There is a very good reason that the vernatherms are set up the way they are in the engines which use aviation (read: thick when cold) oil. If you use a thermostat, and there are periods of no flow through the oil cooler, you might run into problems in really cold (winter, north, high altitude) flight with oil overheating.
 
yes the kitfox, rotax, does use oil that may be thinner. I use 10w40 year round and have been using Amzoil motorcylcle oil. Before that I used Honda motorcycle oil that was 50/50 synthetic. Now if that which you state is a problem, I suppose a person could rig a heat system, like a heat strip along the bottom of the cooler to keep the oil from gelling. Somehow I don't think it will be a problem. But then again...
 
AlexPeterson said:
If you use a thermostat, and there are periods of no flow through the oil cooler, you might run into problems in really cold (winter, north, high altitude) flight with oil overheating.
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That is not accurate. The oil thermostat I am referring to always curculates 10% of the oil through the oil cooler to keep it warm and avoid what you are talking about. It never shuts off oil flow through the oil cooler, only regulates it at 180F.

http://www.perma-cool.com/Catalog/Cat_page14.html

I totally agree with Steve, the oil thermostat is a great devise. It seems it has been overlooked by RV builders. Using a thermostat built for oil coolers seems like a no brainer. Take a good hard look at it and let me know the down fall side, I can't see any.

The upside? No more duct tape on the oil cooler! No more worrying about was it enough tape? Not enough tape? Going cross country do I need to stop and take some off when the oil gets hot?

The shutters block 50% of the air flow though the cooler.

Anyway, enough said. Take a look at it and see what you guys think.
 
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I like duct tape as much as any guy

But using it to control oil temps is probably not the best idea.

Did you install and use the Vans oil cooler shutter system? If so, did it work?

Many people here use a simple flat piece if metal that covers the back of the oil cooler and opens/closes using a simple knob in the cockpit.

If you decide to try the thermostat discussed, consider posting an oil flow diagram so people can advise on any possible problems.
 
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Geico266 said:
That is not accurate. The oil thermostat I am referring to always curculates 10% of the oil through the oil cooler to keep it warm and avoid what you are talking about. It never shuts off oil flow through the oil cooler, only regulates it at 180F.

http://www.perma-cool.com/Catalog/Cat_page14.html

I totally agree with Steve, the oil thermostat is a great devise. It seems it has been overlooked by RV builders. Using a thermostat built for oil coolers seems like a no brainer. Take a good hard look at it and let me know the down fall side, I can't see any.

The upside? No more duct tape on the oil cooler! No more worrying about was it enough tape? Not enough tape? Going cross country do I need to stop and take some off when the oil gets hot?

The shutters block 50% of the air flow though the cooler.

Anyway, enough said. Take a look at it and see what you guys think.
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Greetings,

It would be interesting to know how the valve can decide that 10% goes through the oil cooler without knowing what the resistance in the oil cooler and associated lines is compared to the other pathway (engine). The valve will probably proportion 10% if the fluid resistance in both pathways is equal. However, that will likely not be true if -10F air is blowing unhindered through the oil cooler. Then, the positive feedback loop begins - the oil gets thicker, causing even less oil to go through it, which in turn cools the oil in the cooler even more, and so on and so forth. The valve being discussed is not a positive displacement pump, which automatically puts 10% through. It can only be fluid resistance based.

I would proceed with extreme caution with this setup using aviation oil.

A very simple solution is to use 3 or 4" scat to a firewall mounted cooler, and install a cockpit controllable throttle in the plenum above the cooler. When the OAT is below about 20F, I close this throttle completely. Even at -18F (the coldest I've flown my plane so far), the oil temps were around 160F.
 
Alex, that is a good question / comment, one that I had not thought of, but after reading the web site ...

Copied from the web site....

When oil temperature exceeds 180?F the thermostatic valve closes, allowing 95% flow through the oil cooler. At temperatures below 180?F the valve is open, with 90% of the oil bypassing the cooler. The remaining 10% of the oil flows through the cooler, maintaining constant system pressure, preventing air pockets and eliminating cold oil shock. Flows up to 20 gallons per minute (GPM). Rated to 200 p.s.i. Thermostat mounting kits containing four brass fittings, four stainless steel hose clamps and two nylon tie mounts are sold separately.

I'm not here to argue pros & cons. All I know is I have an aircraft (just bought it) with one installed and it works flawlessly to maintain the oil temp at a constant 180F in any ambient air temp, under any load condition. I think it is worth investigating for the RV series aircraft engine installations.
 
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Geico266 said:
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.
Click to expand...

Does the oil temp really need to get to around 200 degrees (at the temp probe) to get rid of water from the oil?? My 0-320 Lycoming manual lists a desired oil temp of 160 and a max oil temp of 210, below 10 degrees OAT. Even if the oil does not get to 200 degrees at the temp probe it will certainly get to hotter temps as it is sprayed on the cylinder walls and as it passes through the cylinder head area. :confused:
Fin 9A
 
As long as you've got cool spots in the crankcase, you've got condensation continuing to occur. If it's hot in one location and boils off the water there, the water vapor is still in the case and will recondense in a cooler spot. Keep everything hot and the water will stay in the vapor phase and eventually be purged from the case.
 
Finley Atherton said:
Does the oil temp really need to get to around 200 degrees (at the temp probe) to get rid of water from the oil?? My 0-320 Lycoming manual lists a desired oil temp of 160 and a max oil temp of 210, below 10 degrees OAT. Even if the oil does not get to 200 degrees at the temp probe it will certainly get to hotter temps as it is sprayed on the cylinder walls and as it passes through the cylinder head area. :confused:
Fin 9A
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According to Rotax, yes, the temps need to reach 215 every flight.
 
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