High Oil Temps - Vernatherm question - opinions, please!

I'm still trying to get my oil temps a bit lower, and so I took the advice of another builder and checked out my oil-temp sender then my Vernatherm. The oil temp sender (reading from my MGL EFIS) was within 1 degree of my digital meat thermometer, so I'm good to go with that.

The Vernatherm is a different story, though. When I took it out, I looked inside the oil filter adapter and noted that the gasket seems to be interfering with the Vernatherm seating in the oil hole. See the first picture below. In the first 2 pictures, you can see the edge of the gasket is actually "dimpled" around the edges from where the Vernatherm contacted it. I'm guessing that the upper 1/3rd of the hole didn't seal, and this could be my problem.

The 2nd picture is what I did to try and correct this with the new gasket, and the 3rd picture is with everything put back together. Note that there is a lot more clearance around the hole in the last picture.

I have 3 questions from this whole experience, and I would greatly appreciate any help.
1 - Is it OK to trim the gasket like I did? Has anyone ever seen the oil adapter gasket block the hole like that?
2 - I couldn't find in my engine manual a torque value for the Vernatherm. Does anyone know what it is?
3 - My Vernatherm had a flat aluminum (?) washer under the head. No copper gasket. Is that OK? Is it OK to reuse it?

Thanks in advance!

300 inch pounds

According to my Superior manual.

The right-angle oil filter adapters are bad designs, and this points out well why that's the case. On a normal oil filter housing there is a chamfer that the vernatherm face seals against. In the case of the right-angle filters, it uses the hole the oil comes in thru on the accessory case and as you can see it can never seal well against a sharp edge, let alone one that has a piece of gasket covering it. Yes you should cut away the gasket but I would expect even with it cut away the seal is marginal at best.

I know you must already know this, but the Vernatherm must seat tightly for the oil to flow through the oil cooler. Also, take a look at the Vern. itself and make sure that the camfer is smooth and also check the seat for same. You can also check the Vernatherm by heating it in oil to 185 deg. and verifying that it extends fully, which is .160 inch minimum. As Bob said, the right angle adapter is a poor design. I would cut the gasket so as not to let it interfere with the vernatherm extending into it's seat.

Thanks guys. By the look of the Vernatherm's contact point, it looked like it had wear marks all the way around. I believe the hole that it fits in did have a slight beveled edge. I was just really surprised that the gasket was blocking the Vernatherm from making a full seat.

As noted, the bottom picture is with the gasket trimmed back to allow the Vernatherm to fully seat. I hope this works in bringing my temps down.

I'm wondering if the other guys with ECI kit engines have the same problem. It certainly looks to be a design issue, and I read about a lot of ECI's having high oil temps. I actually bought 2 louvers to put on the bottom of my cowl, but I'd really prefer not to cut holes in it if I didn't have to!

rocketbob said:

The right-angle oil filter adapters are bad designs, and this points out well why that's the case. On a normal oil filter housing there is a chamfer that the vernatherm face seals against. In the case of the right-angle filters, it uses the hole the oil comes in thru on the accessory case and as you can see it can never seal well against a sharp edge, let alone one that has a piece of gasket covering it. Yes you should cut away the gasket but I would expect even with it cut away the seal is marginal at best.

Click to expand...

But isn't the hole in the accessory case the same one that is used for those Lycomings that came with an oil screen rather than an oil filter?

The hole should be suitable for a vernatherm according to Lycoming.

1 - Is it OK to trim the gasket like I did? Has anyone ever seen the oil adapter gasket block the hole like that? Yes absolutely, Yes all the time if the gasket is used without trimming.
2 - I couldn't find in my engine manual a torque value for the Vernatherm. Does anyone know what it is? 300 inch pounds
3 - My Vernatherm had a flat aluminum (?) washer under the head. No copper gasket. Is that OK? Is it OK to reuse it?
Only use the aluminum and I think you will be OK with a reuse one time.

I doubt if trimming the gasket will make much difference with the oil temp....

Good Luck,
Mahlon
"The opinions and information provided in this and all of my posts are hopefully helpful to you. Please use the information provided responsibly and at your own risk."

RE: Different Path

Hi Sonny

In my thread with a similar problem I left you hanging.

http://www.vansairforce.com/community/showthread.php?t=73780&highlight=low+oil+pressure

Like you I have been dealing with the high oil temp but also marginally low
(55 in cruise) oil pressure. Mahlon has given great advice, ECi folks have chimined in, America's Engine ... who built my enigine .... have also given advice, and finally the local A&P has been a help.

The advice has been all over the map. Vernatherm, oil pressure regulator, blocked oil cooler, bad baffling (I have a Robbie Attaway style lid not rubber againts the cowl for my air recovery), and so it goes.

Unlike you I started with the oil pressure regulator. Installed a new heavier spring and guessed at the proper screw setting. No joy on my last flight. Higher oil temps, and as Mahlon suggested very high oil pressure on take off. But the oil pressure in cruise was higher in the mid 60's. But......

On close inspection of the engine compartment during the oil change, oil pressure regulator spring change I noted a line of oil streams heading up the back of the fire wall from the bottom flange. They went up about 3 inches.....sorry know pictures I just cleaned it off with out making the connection that oil dropletts should be going down not up. So maybe my Vetterman four pipe exhaust is restricting air flow thus causing a high pressure area thus ......you get the idea.

So I will be doing some surgery on my cowl to increase the area of the outlet. I am going to calculate the area differential between the inlet and outlet. (I guess it is supossed to be 1 to 1.75)

I also plan on doing the vernatherm check as you are doing to prove / disprove it's function. I read in a Lycoming circular that an easy check is to get the engine above 180 and check the oil cooler lines to see if they are as hot as the oil sump and to also check the oil cooler to see if it it also hot or has cool spot ( indication of air blockage in the cooler).

My plan is to unscrew the pressure regulator screw at least three turns. Go fly and check results. But, if Mahlon is correct temps will probably remain high with the pressure going down down down..... On the other hand maybe ECi and America's Engine folks will be right and I will hit the sweet spot for oil pressure regulation and oil Temp.

Then I will do surgery on the cowl if necessary.

Then the vernatherm...................So I will follow your thread closely to see how your plan works out and to see if you can overcome what some say is the bad design in the oil filter adapter. I have the same setup so maybe that is why I choose the easy route of the oil pressure regulator and hope that it is the culprit.

At the end of the line one of us is going to have joy when we solve this situation.

I have really enjoy all the threads on this issue and especially engine gurus like Mahlon who are willing in give we mere mortals free advice.

PS:Mahlon ....when do you sleep ...... 4:47 AM is pretty early to respond but thanks a bunch or your help!!!!!!!

Frank @ 1L8 ... Fly and Tracken with MT_RTG

az_gila said:

But isn't the hole in the accessory case the same one that is used for those Lycomings that came with an oil screen rather than an oil filter?

The hole should be suitable for a vernatherm according to Lycoming.

Click to expand...

True, and that makes two poor designs...

On my rocket I have removed the expensive vernatherm and put the oil cooler bypass plunger and spring, and will control the oil temps manually with a ball valve.

fstringham7a said:

...
Unlike you I started with the oil pressure regulator. Installed a new heavier spring and guessed at the proper screw setting. No joy on my last flight. Higher oil temps, and as Mahlon suggested very high oil pressure on take off. But the oil pressure in cruise was higher in the mid 60's. But......
...
My plan is to unscrew the pressure regulator screw at least three turns. Go fly and check results. But, if Mahlon is correct temps will probably remain high with the pressure going down down down..... On the other hand maybe ECi and America's Engine folks will be right and I will hit the sweet spot for oil pressure regulation and oil Temp.

Click to expand...

Hey Frank, quick question...I meant to ask this before, but if the minimum oil pressure (by the book) is 25 psi, why are you worried about it "only" being 50 psi in flight? I'd start worrying if it were closer to 25 in cruise, but 50 sounds good to me. What am I missing?

RE: Not Sure

Don't know the answer to that other than I have heard (old age setting in) and can't remember the guru that said it the overall long life of the engine is enhanced by staying above 60 and below 90 in cruise????? I do know ECi put 60 as a minimum cruise pressure.

Maybe Mahlon or one of the other gurus can give the answer

Frank @ 1L8 ... Flying ...

RE: PIX

rocketbob said:

True, and that makes two poor designs...

On my rocket I have removed the expensive vernatherm and put the oil cooler bypass plunger and spring, and will control the oil temps manually with a ball valve.

Click to expand...

Hi Bob

Do you have pictures and diagrams and parts list for this option. And have you flown your rocket ....

Frank @ 1L8 ... RV7A... Flying

Frank, What is your oil pressure at idle hot? Do you have the vacuum pump housing on your engine? Don

fstringham7a said:

Hi Bob

Do you have pictures and diagrams and parts list for this option. And have you flown your rocket ....

Frank @ 1L8 ... RV7A... Flying

Click to expand...

No pics of the valve yet since I don't have it hooked up and haven't flown but got the idea from Larry Vetterman. I do have the bypass plunger installed. The ball valve goes on the oil cooler line and is controlled from the cockpit.

fstringham7a said:

Don't know the answer to that other than I have heard (old age setting in) and can't remember the guru that said it the overall long life of the engine is enhanced by staying above 60 and below 90 in cruise????? I do know ECi put 60 as a minimum cruise pressure.

Maybe Mahlon or one of the other gurus can give the answer

Frank @ 1L8 ... Flying ...

Click to expand...

Where did you read that? I can't find any operating instruction documents from ECI at all. I was told to use the Lycoming materials since they should be the same.

25 psi is min idle oil pressure or bottom red line
55-95 is cruise oil pressure or green arch ( used to be 60-90 but Lycoming changed it a few years back)
115 is max cold oil pressure or top red line.
I would be fixing it, if it had less then 60psi for oil pressure, in cruise, if it were mine.
Good Luck,
Mahlon ?The opinions and information provided in this and all of my posts are hopefully helpful to you. Please use the information provided responsibly and at your own risk."

RE:Vac Area

yakdriver said:

Frank, What is your oil pressure at idle hot? Do you have the vacuum pump housing on your engine? Don

Click to expand...

Hi Don

If I am reading your question correctly I have the SD-8 aux alternator on the Vac pad....

Oil pressure at start up (old spring) was 81 and would be at or about 75 to 80 at t/o. New Spring it was 89 at start up and can't remember the run up temp or pressure and at t/o hit 108

Frank

RE: Info

lostpilot28 said:

Where did you read that? I can't find any operating instruction documents from ECI at all. I was told to use the Lycoming materials since they should be the same.

Click to expand...

It took me a while but I finally found the info on the ECi web site. On the ECi Home page there is a square info position on the left side that says Titan EXP....... http://www.eci.aero/ ...... which takes you to http://www.eci.aero/exp/index_exp.aspx ...... then on the left is a box EXP KIT Egines and hit either Over view Brochure or Engine Comparison Chart.

http://www.eci.aero/exp/eng_comparisons_chart.pdf
http://www.eci.aero/exp/eng_comparisons_brochure.pdf

As far as operating instructions Robbie Attaway, local RV drivers, and info from VAF is what schooled me!!!!!!!!!! Plus this info from ECi

http://www.eci.aero/pages/tech.aspx#breakin

Sonny, I hope this helps. So now the race is on who will get their plane dialed in first. I personally hope it is you so I can learn from you.


Frank @ 1L8 ...RV7A... Flying kinda!!!!!!!!!!!!!!!!!!!!!!

fstringham7a said:

Hi Don

If I am reading your question correctly I have the SD-8 aux alternator on the Vac pad....

Oil pressure at start up (old spring) was 81 and would be at or about 75 to 80 at t/o. New Spring it was 89 at start up and can't remember the run up temp or pressure and at t/o hit 108

Frank

Click to expand...

Reason I asked is that I had oil pressure problems with my engine. My pressure would start out 95psi at 100 degrees oil temp, 85psi at 180 and would fall to 50psi at 230. Idle pressure was 15psi hot. Caused a spun rod bearing. The vacuum housing was on the case but without a gear in it letting the oil bypass. Now start up and take off 85psi, lowest it gets in cruise is 78psi at 220 temp. Idle 40-50psi. Sounds like you might have a missing oil galley plug. Don

fstringham7a said:

It took me a while but I finally found the info on the ECi web site. On the ECi Home page there is a square info position on the left side that says Titan EXP....... http://www.eci.aero/ ...... which takes you to http://www.eci.aero/exp/index_exp.aspx ...... then on the left is a box EXP KIT Egines and hit either Over view Brochure or Engine Comparison Chart.

Click to expand...

Thanks, Frank. I don't know why ECI doesn't make their own manuals...would make sense, no?

As for a solution, I hope this does make a difference...I'm running out of ideas on what to do next. I really don't want to cut holes for those louvers!

RE: I will cut

Hi Sonny

Along with an adjustment to the oil pressure regulator adjustment screw (I need an appropriate name for this). I am going to make a forward cut on the lower cowl exitt tunnel and lower it a couple of inchs. Hopefully this will increase the airflow and thus lower the oil temps.

The only down side it get out the paint gun!!!!!!!!!!!!!!!

Frank @ 1L8 ...RV7A... Flying Kinda

oil temp sender

I had oil temp issues. Ultimately in my case, it required replacing the vernatherm and switching to a new 2-wire oil temp probe, which is less sensitive to electrical interference in the system. The vernatherm was marred and probably sticking a bit. As for the probe, I learned about the 2-wire probe because others have had similar issues with the 1-wire. (I found no grounding issues in an exhaustive search, nor did I have any other probes acting up.)

I have AFS-EMS, and they support a couple different 2-wire probes, and they supplied special calibration instructions to use them. Since replacing the vernatherm and switching to the 2-wire probe, my oil temps are rock solid +-187F.

Good luck.

Update

OK, still trying to pin down the high oil temp issues. The OAT today was about 5 degrees warmer than the last time I flew, and apparently I got my oil temps down a couple degrees. Not great, but at least going in the right direction. I actually peaked at 218 degrees (F), but I was running the engine a little harder and it was a little warmer outside, so I thought I may have made things "better" by trimming the gasket which was blocking my Vernatherm from fully seating.

So, I'm still looking for alternatives because I don't want to cut holes in my cowl for the louvers. My hangar neighbor had an oil filter cooler that he's going to let me borrow to see if that helps. Has anyone used one of these, and do they work? He also mentioned putting a blast tube on the filter. What do you all think?

Last idea for the day...ECI recommends Phillips 20/50 X/C pretty much year 'round. Would going with 100W help oil temps?

Just as an idea of how I was flying today, here's a picture of my EFIS with all of the flight parameters.

OAT 83 degrees and 197 oil temp. Not all that bad. I'd love mine to run that cool. Cyl head temps are a little high, might look at that. When I run lean of peak my CHTs come down 40 degrees and oil temp 10-15 degrees. Your oil pressure is a touch low 75 would be better. Don

How many hours on your engine since new cylinders? New cylinders will run hot for the first 10-20 hours.

To make sure your oil cooler is actually working, I would plug up the inlet air and see what it does to your oil temps.

Do you have a return ground from the engine to the airframe?

Have you calibrated your probe in boiling water?

Just some thoughts....

Your CHTs look a little high, but would be normal for a break in period.....

yakdriver said:

OAT 83 degrees and 197 oil temp. Not all that bad. I'd love mine to run that cool. Cyl head temps are a little high, might look at that. When I run lean of peak my CHTs come down 40 degrees and oil temp 10-15 degrees. Your oil pressure is a touch low 75 would be better. Don

Click to expand...

Hey Don, the oil temps are 216 (F). The 197 is the heading!

Trust me, if they were 197, I wouldn't be complaining! Heck, if I could drop them 10 more degrees, I'd be satisfied.

Bill.Peyton said:

How many hours on your engine since new cylinders? New cylinders will run hot for the first 10-20 hours.

To make sure your oil cooler is actually working, I would plug up the inlet air and see what it does to your oil temps.

Do you have a return ground from the engine to the airframe?

Have you calibrated your probe in boiling water?

Just some thoughts....

Your CHTs look a little high, but would be normal for a break in period.....

Click to expand...

Hi Bill,
The engine has 114 hours. I'm pretty sure the oil cooler is working, but I'm not sure how to prove that without breaking something. Blocking the airflow would put my temps higher than they already are, and I'd rather not go there. The temp sensor isn't an issue...as mentioned in the first post, I tested it last weekend and it's spot on.

lostpilot28 said:

Hey Don, the oil temps are 216 (F). The 197 is the heading!

Trust me, if they were 197, I wouldn't be complaining! Heck, if I could drop them 10 more degrees, I'd be satisfied.

Click to expand...

Sonny,
I am running an ECi IO-360 and had some cooling issues BUT. If I had
216 a year ago I would have been Sh***N in high cotton.

I have stabalized mine from 235-240 to 185. Don't worry about the louvers
but look at the exit air. Gave mine 2.5 inches and saw that drop.
James cowl and plenum and now see
295 CHT
1250 EGT
200 OT
all at cruise 8k and then oil drops to 175-185.
Engine has 125 hours on it.
I think your Verni is working, fixing the gasket helped.

I would fly the DOG out of it at 216*

Bruce said:

Sonny,
I am running an ECi IO-360 and had some cooling issues BUT. If I had
216 a year ago I would have been Sh***N in high cotton.

I have stabalized mine from 235-240 to 185. Don't worry about the louvers
but look at the exit air. Gave mine 2.5 inches and saw that drop.
James cowl and plenum and now see
295 CHT
1250 EGT
200 OT
all at cruise 8k and then oil drops to 175-185.
Engine has 125 hours on it.
I think your Verni is working, fixing the gasket helped.

I would fly the DOG out of it at 216*

Click to expand...

Thanks, Bruce...I know that 216 - 220 isn't horrible, but I really want to get it closer to 200 for longevity of the engine. I think you're probably right with the exit air, so I'm probably going to look into trimming that back this weekend. I can't imagine cutting it forward an inch is going to give me that much more exit area (I'm not going to do the math on that!), but I'll take anything at this point.

lostpilot28 said:

Thanks, Bruce...I know that 216 - 220 isn't horrible, but I really want to get it closer to 200 for longevity of the engine. I think you're probably right with the exit air, so I'm probably going to look into trimming that back this weekend. I can't imagine cutting it forward an inch is going to give me that much more exit area (I'm not going to do the math on that!), but I'll take anything at this point.

Click to expand...

If you interested in engine longevity, you must get those CHT's down. The average shown in the imagine posted is over 400F. That alone will cause high oil temperature. According to engine guru, Mike Busch, 400F should be the red line, not 450. He strongly recommends running at 360 or less for max engine life. At 400F, the cylinders are at 50% strength, according to him.

If you want to get the those temps down, you've got to increase air flow through the engine. There are some who will disagree with that premise but I can state categorically, more air flow improves cooling. This is not rocket science with these simple air cooled engines.

Returning from OSH last Thursday at 8,500' (DA over 11,000) CHT's were 337, 336, 339, 355 respectively. Oil temp was 166 at 75 psi. Engine was LOP about 40F. How come such cool numbers? I have copious amounts of air flowing through the engine. The exit area is about twice the inlet with an enlarged exhaust area and Bonanza styled side vents, and the oil cooler is remote mounted ala RV-10 with a 4" duct feeding air to it.

The image of instruments of your flight at 5,500' reveals that EGT's are running very cool while CHT's are abnormally high - you do have a problem. A rich fuel flow at that altitude should have cooled the cylinders dramatically. Have you tried aggressively leaning the engine? The CHT's will come down running LOP and so will the oil temp.

I would focus on getting more air across the engine. You could have baffle leaks and if that doesn't work, exit area must be increased. Your engine will have a shorter than normal life span running that hot.

Update - and a question

OK, I flew again today...tried to match the flight parameters from last week after I made a couple minor changes.
- I found 4 small gaps around the front plenum area (and a small gap along where the oil cooler meets the aluminum)that needed RTV, but if all of them were even one square inch I'd be surprised.

- I blocked off the heater scat tube port on the right side of the aft baffling. I think that's a 2 inch hole, so probably 3 square inches (pi x radius²).

- Lastly, I wrapped the oil filter in the aluminum finned heat sink that my hangar neighbor let me borrow.

The OAT was 3 or 4 degrees (F) cooler...my OAT guage kept bouncing between 79 and 81 (last time it was 83)...not sure why it's not changing in 1-degree increments. Anyway, other than that, I did the same flight and my oil temps dropped to 209 (F).

My question is how much does OAT affect oil cooling. In the cold months when I fly, I struggle to get my oil temps up to 180 F. Does anyone have a formula for this? I'd like to think that my 9 degrees lower temp was "mostly" from better airflow through the cooler.

And a picture for good measure:

Have you calibrated your probes? I would get a good calibrated thermometer, or use boiling water to calibrate one, then check the oil temp probe in hot oil, making sure that you ground the outside of the probe to the engine, not the airframe. Also make sure that you calibrate it when the voltage is at 13.7 volts, so you will have to hook up a charger or power supply to increase the batt voltage with the engine not running. One other thing you might try is to turn off the alternator in flight and notice when the voltage stabilizes at 12.5 or so and then note what the temp gauge is reading. Most all temp probes are affected by the supply voltage. I would do the same with one of t your cht probes.
One thing to note, your CHTs came down considerably with the mods you made.
To answer your original question, I do not see much of a variation in oil temp between 75-85 degrees, so I can't imagine a couple of degrees would make a significant change.
Tim Olson has a post on how he reduced his cht's by trimming the from of the baffling.

Update

OK, it's been a long time, but I wanted to provide an update to my oil cooling issue. I'll post this in the other thread about measuring cowl pressure, too.

I flew last night because it was pretty hot here, and I wanted to try and match the conditions of the images I've posted on my EFIS in post #23 of this thread. Interestingly enough, I managed to fly with an OAT of 83 degrees which is the same as my flight a year ago with Oil Temps of 218 (216 in the picture). I also tried to match the Manifold Pressure, density altitude, and RPMs...all nearly identical.

There were a few things that were different between the first picture and this one - the heater scat tube hole is blocked, I closed up a few more small holes in the plenum with RTV, and I added the exit ramp (curve, whatever).

The results are that compared to nearly identical conditions a year ago, my temps are down 7 degrees (this picture doesn't show that I actually peaked briefly at 211). I do think that blocking the heater scat tube is responsible for about half of that. If you look at post #31 above (the only difference being the scat tube blocked off) the oil temp is 209...BUT, outside air temp was cooler by 4 degrees (F).

I was hoping for a few more degrees from the exit ramp, but since I was only on the high side of normal anyway, 7 degrees lower puts my margin at a very comfortable level for me. I think I'm done chasing solutions now!

My advice for anyone looking for a way to lower the oil temp is to build the ramp...it surely can't hurt, and even if your gain is small, it's still a gain!

Frank, if you're reading this, I hope you try it and post your results.



Just for easier reference, here's the picture from 1 year ago:

Sonny,
Thanks for the update. Glad to see that you have been able to make some measurable progress. I also noted that your CHTs dropped ~20 degrees with the improved cooling flow.

As a data point, can you share your oil consumption?

Tks,

Mike

Sonny, any speed change with the small exit fairing?

Looks like TAS was 177 (no fuel flow indicated) last year, it shows 189 (fuel flow 14.5) this year.

Hey Mike, good observation. I didn't look at that because CHT's weren't a major concern...but I'm glad to see they're lower, as well.
edit: forgot to reply to your oil consumption question. My engine uses less than 1 quart every 25 hours...probably closer to 1 quart every 35 to 40 hours.

Dan, I didn't do a top speed run...yet. But I will...very curious to see if this all made it faster or not.

RErogress N74Bz

It looks like your making progress on the Oil Temp Problem. Like you I have been working on this problem in BUZZ for the past year plus. House remodel for the wife has slowed me up some what. I am not prepared to give a detailed report on my progress but will say that I cut the exit air ramp and lowered it by 2 1/8 inches. This helped but not fixed the oil temps to my satisfaction. But both the cooling of the oil and also the CHT's were helped. This was the last in the list of things I have done. The only problem with this I now have to pull out the paint gun ........The only other thing left to do and I probably will not do this is to eliminate the oil squirters.

This next month I will have the time to give a more detailed report that may help other and will probably cause me to want to put on the old flame suit

lostpilot28 said:

- I blocked off the heater scat tube port on the right side of the aft baffling. I think that's a 2 inch hole, so probably 3 square inches (pi x radius?).

My question is how much does OAT affect oil cooling. In the cold months when I fly, I struggle to get my oil temps up to 180 F. Does anyone have a formula for this? I'd like to think that my 9 degrees lower temp was "mostly" from better airflow through the cooler.

Click to expand...

How exactly did you block the hole? That sounds like a good summer option, and probably pretty easy to install and remove as needed.

I can't put a formula to OAT versus cooling, but I'd say OAT affects my oil temps a lot. I was flying back to Colorado from the Midwest yesterday, and over western NE the OAT got up to 101 degrees even though I was at around 2000 AGL. About that time my oil temps started climbing towards 220. I made the decision to find cooler air and step climbed until it was about 88 degrees at about 5000 AGL. At the top of the climb oil temps hit 225 for a minute or two before dropping back down to 213. I was considering which airport (and 105 degree surface temps) to go to if I couldn't stabilize the temp. During my flight out last Thurs., when it was cooler, my oil temps in cruise were more like 170-190. My guess is that the 13 degree OAT change dropped the oil temp 5 or 6 degrees.

Mile High Relic said:

How exactly did you block the hole? That sounds like a good summer option, and probably pretty easy to install and remove as needed.

I can't put a formula to OAT versus cooling, but I'd say OAT affects my oil temps a lot. I was flying back to Colorado from the Midwest yesterday, and over western NE the OAT got up to 101 degrees even though I was at around 2000 AGL. About that time my oil temps started climbing towards 220. I made the decision to find cooler air and step climbed until it was about 88 degrees at about 5000 AGL. At the top of the climb oil temps hit 225 for a minute or two before dropping back down to 213. I was considering which airport (and 105 degree surface temps) to go to if I couldn't stabilize the temp. During my flight out last Thurs., when it was cooler, my oil temps in cruise were more like 170-190. My guess is that the 13 degree OAT change dropped the oil temp 5 or 6 degrees.

Click to expand...

Duct tape! It's probably not a great solution, but it seems to work pretty well. At 101 degrees (F) I don't think I'd expect oil temps under 200. You still have a 25 degree margin at 220 before redline...but I'll admit that it makes me really nervous when mine got that high.

Sonny,

replying to your question on how outside temps affect the oil temperature- a lot! On my ECi, I have the same issue with high temps. On a flight last week of 300 mile each way, the trip out had clouds which kept me low with hot outside temps (2500'). OAT was 85-88F. Oil temperature after stabilizing about 30 min into the flight was just over 220F at 2400 RPM on a fixed pitch prop. Did not make me comfortable. On the return trip at 5500', OAT of 62F, oil stabilized at 201F, much better. Like you, in the winter I can't get oil temps above 180 on even a mild day, but once the summer weather hits I struggle. CHT's on the hot day were about 380F.

I just ordered a replacement for the Niagra cooler from Pacific Cooler. Wayne tells me it's much more efficient due to the increased cooling fin surface area (about 50% more). Part # 8001602, $484. This is a direct replacement as far as fit. I'll report back with data from the results once I install. I'm hoping this won't have me sweating high oil temps on my first Oshkosh trip next month!