McFly

McFly

Well Known Member
With the warming temperatures, my oil temperature has skyrocketed. I am showing 210 degrees in cruise when it is only 80 degrees on the ground. I am wondering if it is a problem with the vernatherm since the my oil temp was 160 or so when the surface temperature was in the 50s. My CHTs have always been rock solid at 300-325. I do have a plenum with the cooler mounted behind #4. Ideas?

It may be time to buy a new oil cooler since it looks to have developed a leak (the jury is still out but it looks like it is coming from the cooler and not the fitting). I would like to replace it with a unit that cools better AND has the same footprint. Is there such an animal? Thanks for the help
 
I'm guessing that you used the crummy cooler that comes with Van's FWF kit. I went to a Stewart Warner 8406R and saw an immediate measurable drop in oil temp across the board. Call the guys at http://www.oilcoolers.com for more info. Spruce carries the 8406R as well.
 
temps & Vernatherm

I am no expert but I would have thought that perhaps you have another problem. If, and that is important, the differential was (160 -55) about 105 deg before it should now be in the order of 85 +105 = 190 now. Since you say it is 210 there is a significantly larger differential. A working vernatherm should improve the situation from there, since it should have opened and pushed oil into the cooler. Perhaps its blocked?

The vernatherm is easy to check if you remove it. It visibly extends when it hits I around boiling point. The exact number is engraved on it.

Good luck.
 
There is a lot of information that is required to assess high oil temperature. What engine is it? HP? Stock engine? What airframe? How is the cooler actually mounted? What is the condition of the baffle work? What gauge is being used to determine CHT? Has the gauge been calibrated? What power settting is being used in cruise?

You can be sure Van's Aircraft is running the coolers they sell and you can be sure they have no "agenda" for hiding their results.

It seems to me that instant responses like "....I'm guessing that you used the crummy cooler that comes with Van's FWF kit......" are of little value.
 
Chickenlips said:
It seems to me that instant responses like "....I'm guessing that you used the crummy cooler that comes with Van's FWF kit......" are of little value.
Click to expand...
I don't have enough fingers to count the folks I know personally who switched from the AeroClassic cooler Van's sold us all in our FWF kits to a Stewart Warner oil cooler. Everybody I know who did saw a marked improvement that resolved their issue. So you can say there's no value in that if you want, or we can just be honest about these things.
 
I'll tell ya what. I can be slightly more constructive than that: "With oil coolers, you definitely get what you pay for."

Hugh, it's most certainly worth checking your vernatherm to rule that out, but if that's not the issue, then the answer to your question of replacing your oil cooler with a better one with the same footprint...well, I believe I've provided that info. Somebody didn't appreciate it, but hopefully you might.
 
I contacted Aero Sport Power about my oil temps. On the way back from the paint shop about a 1.1 hour flight they were running in the 205 range at 75% power on a not very hot day. I can get them lower by running less power but I'm still in the 190's.

Anyway, Aero Sport said they can send me a new venatherm. I dont know if they adjust it so it opens/closes at different temps or if it will just be a replacement.

However I should probably just upgrade to the SW one like Dan suggests.
 
Not trying to rain on my parade Dan, but...

With my engine and setup the Vans (cheep) oil cooler has been working just fine. I only have an IO-320 in a RV9A, so probably am not making as much heat and only have 50 hour of time on my plane, so things may change.
My highest temp last summer were about 195 degrees. :cool:

Kent
 
Somebody didn't appreciate it, but hopefully you might.
Click to expand...

Dan, your advice is much appreciated!

The engine is a MattituckTMX 0-360 with 9.2 compression, 1 mag, 1 LS ignition. I am using a metal plemum with the cooler mounted on the baffel behind #4 on a RV-7. I am using Vans guages,the oil temp has not been calibrated but think it is in the ball park (in other words I think the temp is actually increasing and the movement on the guage is proprtional to the temp increase). Cruise RPM is 2200-2500 (it was running cooler during engine breakin when I was running a 2600).

I am suspecting the vernathem and will investigate this first. However; if my oil cooler is the source of the oil leak, I'll be in the market for a new one regardless of how the vernatherm checks out. Thanks Guys.
 
kentb said:
...I only have an IO-320 in a RV9A, so probably am not making as much heat...
Click to expand...
Exactly. In my case, I have an angle valve 200hp IO-360-A1B6. The angle valve engines shed considerably more heat into the oil than their parallel valve brethren, partly due to oil squirting on the piston skirt.

In my case what I didn't know hurt me. At least at the time when I bought my FWF kit, Van's sold the exact same oil cooler for the big heat-shedding 200hp angle valve as they did for the O-320! Little did I know. My fault for not doing the research up front and blindly just "taking what they gave me."

At this point my "agenda" is just to try to pass this 20:20 hindsight on.

If you have a bone stock O-360 or smaller, then the smaller AeroClassic oil cooler will likely do the job in all but the most extreme conditions. If you add heat generating attributes such as higher compression & EI (like Hugh mentioned), then you will likely want to look into a BETTER and possibly bigger oil cooler.

Just my 9 cents (passed 2 cents long ago). :rolleyes:
 
McFly said:
Dan, your advice is much appreciated!

The engine is a MattituckTMX 0-360 with 9.2 compression, 1 mag, 1 LS ignition. I am using a metal plemum with the cooler mounted on the baffel behind #4 on a RV-7. I am using Vans guages,the oil temp has not been calibrated but think it is in the ball park (in other words I think the temp is actually increasing and the movement on the guage is proprtional to the temp increase). Cruise RPM is 2200-2500 (it was running cooler during engine breakin when I was running a 2600).
Click to expand...
When I started flying my 6A 7 years ago I had high oil temps. I switched from the old style Positech cooler to the SW 8604 and my temps went down but would still run 200-210 in cruise depending on power settings. I had some engine problems 3 years ago that forced me to make a precautionary landing on a private grass strip east of Denver. While working on the solution I removed my metal plenum top and ditched it in favor of regular baffle seals. (Good move Gary) The drop in oil temps and CHT was amazing with the new setup. I now run 180F at cruise with an occasional 190 at high power settings and low altitude. It could be your plenum. What are your CHT running at. Normal on my 6A is 350-370F on a summer day and I'm hard pressed in the winter to get over 350.

If you replace the cooler don't overtighten the fittings. NTP fittings are tapered (you know that) and can crack the cooler if installed to tight.
 
What are your CHT running at.
Click to expand...

My CHT's in level flight, pretty much regardless of power settings, are 300, 325, 325, 325. This has been the case since the engine passed 5 hours. I think the plenum is doing its job.

Initially the oil temp was too low (150 if memory serves) but my first flights were during cold ambient temps (low 40s maybe high 30s). My oil temps have been increasing but way faster than the ambient temps. The more I think about it, the more I suspect the vernatherm is the culprit.
 
Hugh,
A bad vernatherm and inefficient oil cooler will show up the same operationally. In other words, if the oil is hotter then the cooler can shed that heat, the oil temp goes up. If it is hotter because the vernatherm isn't closing and sending the oil to the cooler, then it's the vernatherm?s fault but if the vernatherm closes and forces all the oil to a inefficient oil cooler that doesn't shed the heat, then it is the coolers fault or the airflow through the cooler's fault. From the pilot?s perspective, all three scenarios will look the same. As the cooler doesn't shed the heat, for what ever reason, the oil temp will rise. If you want, I can send you another vernatherm to try, or you can remove what you have and heat it up. It should be fully expanded by 180 degrees.
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."
 
Thanks Mahlon and thanks for the offer. I'll try heating mine up first. I'm curious to see how this all works.
 
Van's cheap cooler OK by me

I don't dispute that other oil coolers are better. I don't dispute that a vernatherm could be a problem. Ok, that said, I have the Superior IO-360 180 HP engine, FP prop. Absolutely the only time I ever had high oil temp was when I had blocked the exit air with a piece of metal on the back side of the oil cooler - for the winter - and we had a 70 degF day AND my wife said "how fast will it go?". No amount of summertime climbs even during break in ever made it hot. On a 20 degF day at under 75%, even with the blocked exit air, I can't get the oil past about 120-130 degF. I have the GRT EIS, so I'm confident my temps are accurate. They are correct before startup, too.

This does not demonstrate "better" oil cooling with the cheap unit, but I suspect it does demonstrate that the SJ cowl and plenum work very well. My cooler is mounted about where Van's said to mount it behind #4 except it had to be lowered for the plenum and cowl difference. So I'm suggesting that the overall subject of cooling should be looked at, not only one component.
 
Oil temps too low?

hevansrv7a said:
...I can't get the oil past about 120-130 degF...
Click to expand...

Unless I'm misunderstanding you, or Lycoming recommendations, you've got a problem.

As I understand it, your oil temps should at least get to 170 degF, otherwise you're not getting the moisture out of your oil.

I hope I've missed something here. What are your temps when the OAT is higher than 20 degF?

George
 
Last edited:
grjtucson said:
Unless I'm misunderstanding you, or Lycoming recommendations, you've got a problem.

As I understand it, your oil temps should at least get to 170 degF, otherwise you're not getting the moisture out of your oil.

I hope I've missed something here. What are your temps when the OAT is higher than 20 degF?

George
Click to expand...
No, you didn't misunderstand. I need to do more blocking to fly in winter. My oil temps in summer and fall were 180 degF, right where they should be. Thanks, though. My point was not that such low temps are good, only that with good overall cooling and airflow, the cheap oil cooler is OK.
 
Went out flying yesterday one of the hottest days I've taken my plane up. On 100 nm trip at 7500' with OATs on the ground of about 85F, I was getting oil temps around 220F! eeeks... not good. After about a 30 min shutdown at 2J3 (Pierre... didn't see you around!) flew to MLJ and then on back home. Temps still crept up there but after powering back a little I got the temps down to 213F.

What's this mean? I ordered a new Stewart Warner 8406R today. Will post my results as soon as I get it installed and flying. CHTs were all looking good with 400F max in the climb and 375 hottest cyl in cruise.
 
dan said:
I'll tell ya what. I can be slightly more constructive than that: "With oil coolers, you definitely get what you pay for."
Click to expand...

Right again Dan. And yet people prefer to believe they can buy the same quality at half the price.

There's absolutely no comparison in terms of quality between the Stewart Warner 8406R and the el cheapo Aero Classic that Vans sells. Apart from being more efficient the Stewart Warner is fully aluminium welded, whereas the Aero Classic is vacuum brazed.

Cheers Bob
 
Preliminary Results

Well I tested the vernatherm and it checked out fine. My wife saw the pictures of the vernatherm cooking on her stove using her cooking thermometer :eek: Let?s just say, don?t try this at home, at the very least destroy all the evidence. :D

During my control flight the surface temp was 80 degrees; my oil temp was 210, 3500? full rich.

I fabricated a diverter which I had hoped would funnel more air through the oil cooler. It seemed to help and the oil temp dropped to 190 degrees (surface temp was 75ish).

I installed the SW cooler Saturday. This seems to have helped as well. My oil temp was 170 when the surface temp was 70. So I am now running an oil temp 40 degrees cooler than my control flight when the surface temp was 10 degrees cooler.

The gains from funneling the air were as good as the gains from the new cooler and cost nothing. I do have a home grown plenum so the ?air funneling? gains may be a special case for my installation.

Right now it looks like I should be able to make it though the summer with decent oil temps. It also looks like Winter ops will require some tinkering to get the oil temp in line but that?s an easier problem to deal with.
 
Also interested in the diverter pics!! Please!

Flew yesterday with the new SW8406R oil cooler. Ground temps were in the mid 40's (this is April?) and my oil temp at 7500' in cruise mode was right at 170F. My GRT OAT probe said 28F. CHT's were 350 max when usually they run around 375F or so. The cold air is doing its job.

Still waiting on warm air (for my sanity... hate cold wx! this coming from someone who grew up in the snow belt of Lake Erie).
 
Picture coming in a few days

My plenum roof makes a 90 degree angle with the rear baffle wall where the oil cooler is mounted. I believe that this right angle causes the air to just swirl around in an eddie (this is just my redneck engineering hunch, I have no proof). The ?diverter? is a cone shaped piece of metal mounted between the cooler and plenum roof to smooth out this right angle.

If you don?t have a plenum and built baffles according to plans, I guess you could do the same thing by fiber glassing a ramp on the top cowl to divert the air downward to the cooler.

I can get a picture if you don?t mind waiting a few days (I just got the plane back together). When you see it, your reaction will most likely be ?no way?. It is fairly cheesy looking and there is not much to it.
 
Diverter Pictures

Sorry guys, a few days somehow turned into a couple of months. :eek:

Inside plenum, oil cooler without diverter

1000503xm4.jpg


Inside plenum, oil cooler with diverter installed

1000502gg3.jpg


Sorry for the long delay. I hope the pictures shed some light.
 
oil cooler problems

T0 McFly and Will Scott:(and anyone who can help):
Did you solve your problem with the SW cooler?
I am using mid size positech and following overhaul of bottom end have been exp. higher temps in hot weather than before. (460 hrs prior to OH with no prblems on temp).Currently using mineral oil for breakin of new cam and crank brgs. (25 hrs total since oh w/ an oil change at 10hrs). Does min. oil run hotter? I get 215 in cruise at 24-25 at 3000' (o 320 D1a 160 hp with cons spd prop). If land and take off after that event temp climbs to 240. (outside air 31C). Yesterday checked oil temp in sump and it was at 230 with 210 showing on the gauge.
Thanks
 
SW was the fix for me

The SW cooler was the fix for me but I was replacing the Van's SW imitation oil cooler (forgot the brand sorry). My impression is that the Positech coolers dissapate more heat than Van's units so it may not be an apples to apples comparison.

FWIW I am still running mineral oil but will change over on the next oil change (48hrs). I hope others will have more/better suggestions. Good luck.
 
Changed oil.....

I fly a RV-4 with CS O360 with Aeroshell 100 (50 wt). Kept getting higher
oil temps on climb out at a standard day up to about 215 degrees. A friend
from Prescott suggested I do what he did and switch to Exxon Elite 20-50
synthetic oil. BINGO!! Temps dropped about 30 degrees! Might give it a
try.
Woody
 
EH??

pukingdawg said:
I fly a RV-4 with CS O360 with Aeroshell 100 (50 wt). Kept getting higher
oil temps on climb out at a standard day up to about 215 degrees. A friend
from Prescott suggested I do what he did and switch to Exxon Elite 20-50
synthetic oil. BINGO!! Temps dropped about 30 degrees! Might give it a
try.
Woody
Click to expand...

How?

Frank 7a
 
I believe my SW oil cooler has helped tremendously. While I don't have any hard scientific data I believe the change was worth about 15 degrees on average using Philips 20W-50 X/C oil. Right after I made the change I never saw the temps get above 185 - but that was back in April/My time period. However here in Georgia we've been baking lately... and my temps have increased as one would expect. The hottest I've seen lately on my oil has been about 205-208 region and this was on a really hot day.

Just the other day Alan and I took a look at my oil cooler installation. We broke out the pro-seal and filled in some gaps around the perimeter as well as put a pop rivet on the baffle material at that corner. Done a little flying on another hot day and now my temps are under 190! That was a local flight and I wasn't stressing the engine but I did see some improvement.

I have a case of Exxon in the hangar ready to go for the next oil change. We'll see what kind of temps that brings!

I'm a happy SW convert.
 
I do what he did and switch to Exxon Elite 20-50
synthetic oil. BINGO!! Temps dropped about 30 degrees!
Click to expand...

Interesting. I am just shy of 50 hrs but decided to change from mineral oil to Exxon Elite this weekend since I have a big flight ahead of me Thursday(Arlington). In cruise at my little old lady power settings (2300 rpm @ 19") my CHT's are 300, 325, 325, 325, OT is 180-190. I'll report back after Arlington with my numbers.
 
Yes but

McFly said:
Interesting. I am just shy of 50 hrs but decided to change from mineral oil to Exxon Elite this weekend since I have a big flight ahead of me Thursday(Arlington). In cruise at my little old lady power settings (2300 rpm @ 19") my CHT's are 300, 325, 325, 325, OT is 180-190. I'll report back after Arlington with my numbers.
Click to expand...

Where is the mixture at those power settings. Are you running ROP or LOP?

LOP has a big downward effect on CHT.

What was the OAT?

Frank 7a
 
Where is the mixture at those power settings. Are you running ROP or LOP?

LOP has a big downward effect on CHT.

What was the OAT?
Click to expand...

Most of my flights are down low at full rich. My one cross county thus far (50 miles in this thing is not a cross country), I flew high enough to lean (6500'/7500') ROP (the old fashioned pull it till it runs rough and push it in a little bit). The ambient ground temps have run from hot to stupid hot (85 -110). Once in cruise the CHT's always fall in the 300 to 325 range. The OT varies more than the CHTs with the ambient temps but I have not seen 200 since installing the SW oil cooler. I do have a plenum which I assume helps

I was just wondering how the Exxon Elite will effect my numbers. I'll know next flight and report back.
 
I too am having oil temps in the 210 range after installing the Vans baffel to keep temps high in the winter. I assumed it was the baffel so I took it out and the temps are still high. So I guess I need a SW oil cooler.

If it ain't one thing it's another. :cool:
 
Oil temps after switching to Exxon Elite

Interesting. I am just shy of 50 hrs but decided to change from mineral oil to Exxon Elite this weekend since I have a big flight ahead of me Thursday(Arlington). In cruise at my little old lady power settings (2300 rpm @ 19") my CHT's are 300, 325, 325, 325, OT is 180-190. I'll report back after Arlington with my numbers.
Click to expand...

My plane has not shown any temperature differences since switching from mineral to Exxon Elite. Your mileage may vary.
 
Another plane, another update

A friend purchased an RV-6A that runs hot in our neck of the woods.

I made a diverter out of baffle material that I was able to mount even though his set up is the standard baffle material to upper cowl. It had no effect whatsoever on the oil temp.

Although the diverter seems to be a real benefit for my plane, it is useless on his. I guess there is no need to apply for a patent.
 
Diverter Picture

Hugh,
Could you post the diverter picture again?

For some reason I don't see it on the previous post.

I'm very interested in the oil cooler info / systems as I am close to getting FWF components.

Thanks much.
 
I've read (and Applaud) several threads regarding the Aero Classic oil cooler being correctly referred to as "cheap", this oil cooler in this picture showing the plenum and scat tube as a kit is an Aero Classic and once again you'll get what you pay for. Let me explain the 4 major coolers useable on an RV available today-
1st is the aforementioned Aero 800075 unit which in my opinion should be pulled from the shelves and scrapped.
2nd is the Niagara 20006A, (formerly Harrison 8526250)a very good unit and great alternative to the pricey
#3 Stewart Warner 8406 and then there's the #4 Positech #4106...robust and inexpensive but won't do much for cooling.
So there are the 4 players-Aero Classics company was started by a couple of former Harrison and Niagara employees and started off well until they ran out of money, the name was taken over by Pacific oil coolers which is also one of the largest Stewart Warner dealers in the US so they'll sell you either, they'll still make a profit so they don't really care, but the expertise that began with the real engineers is no longer there. Unknown to many is the fact that Niagara Units are still available and not through Pacific but factory direct at 419-239-8800...The Niagara 20006A is by far the best value - a little more expensive than the Aero but less than the SW8406 and has a solid successful history.
 
You must log in or register to reply here.