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Oil cooling on C-90 Super Cub?

J

jhawkins

Registered User
Hi all,

As the weather here in NM warms up, my oil temps are doing the same. On the last flight, they hovered around 210-215 after climb and never came down much below 200. While I realize that's below the redline, I'd rather they be a bit lower, especially after such benign flying in reasonable temps.

I've owned the airplane for about 9 months and am preparing for the annual. Inspecting the airplane, it's clear that no baffling goes to the oil tank. Is this common on the C90 PA18s? The parts manual lists a few parts for baffling the oil tank, but doesn't show how they fit, and they don't seem to be available anyway. They are:

Figure 30, index # 36 12230-00 - PLATE - Oil Well Baffle (used only with C-90-12F engine)

and

Figure 34, index # 9 12229-00 - BAFFLE ASSEMBLY - Oil Well (used with C-90-12F engine)

Photos of my engine configuration:

IMG_1973.jpg

The baffle hole on the RH side is blocked, as you can see:

IMG_1972.jpeg

My questions are -

Is this a standard configuration for a C-90-12F PA18, or did the previous owner simply forego the installation?

Is there a source anyone knows about for the baffleing?

Your help is greatly appreciated.
 

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Univair is your source. This helped me in the past
 

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Cessna 150 O-200 engines have a baffle that bolt to the bottom of the engine. I believe it would fit a C-90 also. I purchased one recently from a salvage yard for my rebuilt. I'm rebuilding a J-3 converting it to a PA-11 with an O-200. I had a PA-11 years ago with a C-85 that did not have that baffling and it would run up near the red line on a hot day, never went over, but would hover around it. When I changed out the C-85 for an O-200 I installed the baffling along the bottom of the engine..........didn't really seemed to make a difference. I've had friends over the years with the PA-11's which are similar to the 90 Super Cubs and they just seem to run warm. You could install an oil cooler too. They bolt on behind the rear cylinder on the left side to an existing pad. Looks like you have a blocked off air inlet on the Y on your nose bowl. Might utilize that openint and route some scat tubing to blow on your oil tank to see if that would help.........wouldn't cost but a few $$ Good luck.
 
Thanks!

My installation does not include an oil filter, and I'm really trying to keep this bird as light and simple as possible, cost aside. Certainly an option though.


If I don't find any source for the baffle listed in the parts manual, I suppose I will rig up some tubing to dump air from the blocked duct to just in front of the oil tank to see if that makes a difference.
 
show a picture of your engine baffling. and theres also a square box that goes over the oil temp filter part of the accessory housing with a blast tube that can be used.
 
Temps rarely go over 100 here, but when they do, our C-85s run around 210-215. Doesn’t seem to hurt them. We had a Continental engineer give a presentation here a while back. He said “see that green arc? Operations anywhere in that arc are ok.” And note that Lycoming allows 245, also in a green arc. Same oil, very little difference in design.
 
I have a PA18-95 replica, with C90 engine. I fought high oil temps, tried lots of “fixes”. The chiller, the O-200 lower engine baffle which can be made to fit, oil tank baffle, both of which I believe you mentioned. Found both at a salvage yard as well. Scat tube blowing on oil tank with and without baffle, all kinds of baffles and ramps on front cylinders, baffles on the inside of the cowl, seaplane lips on lower cowl, wider side cheeks, larger intakes on front cowl, etc. Finally got tired of nothing working so I installed Steve’s oil filter/ oil cooler adapter (stc'd), temps are now fine on hottest days. Very nice unit, very nice folks to deal with, they later sent out a newer/improved valve free of charge. I too did not want to add weight, however wanted to fly without high temps resulting in low oil pressure and constant worry. Only thing I found that actually worked!
 
tempdoug said:
show a picture of your engine baffling. and theres also a square box that goes over the oil temp filter part of the accessory housing with a blast tube that can be used.
Click to expand...

This ^^^. That little "box" goes around the oil temperature bulb.....So, all it does is cool the sensor, not the oil. Nevertheless, it will lower the oil temperature reading....not the oil temperature, mind you, but....

This was the solution that Piper chose. On some engines, the location of the oil temperature sensor is at the hottest portion of the lubricating system.

On my PA-11, with a C-90-8 engine, the box had been removed. I talked to a few mechanics who all said that was just Piper's way of BSing pilots into being happy with their oil temps, but that as long as the temps don't go over the redline....who cares?

I never worried about it, and, after a few trips to Oshkosh, where it's arguably "warm" and some warm high altitude flights, I never saw the temps get above or even REAL close to red line. And, yes, I did verify accuracy of the oil sensor.

I wouldn't worry about it, unless the temps are really getting close to red line.

If that little "bulb cooler" has been removed, you could re-install it, to make you feel better.

MTV
 
Found with my 95 that opening up that right side hole & channeling air over the oil tank via scat tube helped to drop the summer temps to a max of 200, using W100. With the filter set up on my 90, not really adequate room for that filter cooler but didn’t feel it necessary after introducing the blast air. Major problem with those engines is the very effective heat shroud on the muffler that keeps the oil tank & oil temp sensor fairly toasty...love it in the winter but it’s a PITA in summer heat!


Sent from my iPhone using SuperCub.Org
 
Great info guys! You've all helped a ton.

There is no little baffle box over the bulb, and I don't imagine I'll bother with one as I'm convinced enough that it does nothing. I'd love to install the Steves Cooler STC but with I've got way too many projects at the moment (Anyone wanna buy a PA30 or a pair of 310s?)

I suppose I could justify the Oil Filter STC in that eventually it'll pay for itself in cleaner oil and longer oil change intervals....;-)

Not sure that there's room on my firewall for an oil cooler without rerouting quite a bit of things:

IMG_1976.jpg
 

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Mounted oil cooler horizontally on right side of firewall, ran two oil lines from Steve’s adapter, made up an aluminum “funnel”(drawing supplied by Steve”s) placed over top of cooler, scat tube runs from the nose bowl on the side you currently show as blocked to top of funnel. I remove scat tube from top of “funnel” in cooler OAT’s. Works great!
 
The STC does require the use of an oil filter... Typically the Tempest (formally F&M) filter adapter is used, although there have been a few done with the AirWolf remote filter... We left the oil cooler installation pretty vague by stating it can be mounted anywhere on the firewall with no preference on angle... I also know there have been other installations where they have been mounted to the baffle, engine mount tubes, etc... I even know of one mounted under the aircraft with a custom fiberglass scoop on a home built... also there are several size oil coolers that can be used from 5 core to 9 core coolers... the 5 core cooler is pretty small and would fit really well on the smaller firewall Cubs.. [emoji6]

Any other questions don’t hesitate to ask or even call me at 541-826-9729

Brian


Sent from my iPhone using Tapatalk
 
"Blast tube on sensor".......

Might just as well put tape over the gauge if it make's you feel better. That's what my IA buddy told me to do when I complained about high oil temps on my PA16 Clipper years ago.:roll:

Steve's STC above seems the best "REAL" solution.
 
n40ff said:
"Blast tube on sensor".......

Might just as well put tape over the gauge if it make's you feel better. That's what my IA buddy told me to do when I complained about high oil temps on my PA16 Clipper years ago.:roll:

Steve's STC above seems the best "REAL" solution.
Click to expand...

It seems to me that these little engines have been running “hot” for decades. The blast tube just made pilots happy, when in fact the engine was actually running warmer than we think of as “normal”, whatever that is. On most Cub engines, it’s hard to get oil temps over 180 to cook off the moisture.

Id say as long as these engines aren’t going over red line in oil temp on a calibrated gauge, don’t worry about it. Why add more complexity and more connections to a simple system that’s worked for decades?

MTV
 
-90 on an -11 does tend to run a bit warmer on the oil side. What Mike V. Says.
 
sburg58 said:
Mounted oil cooler horizontally on right side of firewall, ran two oil lines from Steve’s adapter, made up an aluminum “funnel”(drawing supplied by Steve”s) placed over top of cooler, scat tube runs from the nose bowl on the side you currently show as blocked to top of funnel. I remove scat tube from top of “funnel” in cooler OAT’s. Works great!
Click to expand...


I don't suppose I could talk you into posting a photo of your installation?

I ran a 2 1/4" Scat tube from the previously blocked vent to just in front of the oil tank and behind the carb. This seems to have improved things enough for now. Should I decide to do something drastic, I'll install the Steves Oil Cooler.

Thanks again!
 
JP said:
-90 on an -11 does tend to run a bit warmer on the oil side. What Mike V. Says.
Click to expand...

Not all of them, my old C90 11 never got to 160f on the hottest day of the year.Yes gauge worked. In winter most days never got to 100f. But small flat prop. Engine had 2200 hrs on it when I wrecked it and was spotless inside.

Glenn
 
My C90 18 will run up to 215f on a hot day, maybe even a close to redline. I’ve always questioned the oil pressure and temps on the engine. Some say it’s just fine so go fly and that’s what I do keeping a close eye on it. We shimmed the oil pump with 3 washers and got the oil pressure at start up to 39lbs. and normally settling out at 31-32lbs all in the green. Thought I would like to the pressure a little higher so ordered a new spring from continental and installed. On start up saw pressure at 42lbs. and after a long warm up and flight on a cool day it settled out at 38lbs. Next we tried 3 washers and a thin and way to high pressure, around 60lbs. Shut down immediately and went back to 3 washers. My question is it better to run at bottom or the top of the green? I’m inclined to think the bottom as long as it’s in the green. Another question I have is on the oil capacity. The POH says 5 quarts, the dip stick shows 4 and some say to run it at 3. So would really appreciate some advice from long time knowledgeable pilots or mechanics on this little engine. Thanks Chuck.
 
continental wants those small 4 cyls to run about 30-35 lbs pressure. thats where the relief is suppose to start opening.
 
I keep it at 3qts and add some when it gets down to 2.5qts. Any more then 3 and it blows it out. That's on C90 sump and 0200 sump

Glenn
 
I know it is an old thread but I wanted to resurrect it with some data from my PA-11 with a C-90-8. Oil temps were 210 or so on a really hot day (90-95 F) here in NC. I wanted to get the temps a bit lower so when I was at higher density altitudes I would have more margin.

My baffling was not great so I repaired and sealed all that first. Oil temps were not impacted by good baffling and may have been a bit worse. Next, I added a 2" blast tube coming off the left rear baffle (flange fitting was already there) that directed airflow around the accessory case and oil temp probe. This mod dropped my oil temp about 10 degrees. I did see an increase in oil pressure so I know it was not just cooling the probe and the temp check (dipstick) with an infrared temp sensor validated it. The final mod was to install a 2" blast tube from the intake just beneath the spinner (right side) and route that air to the oil tank. This made the biggest difference in a 20 degree drop in oil temps on a hot day.

I am currently running 180 degree oil temps on the hottest of days backed up by a check with the infrared thermometer on the dipstick. The cool thing about this is that for cold weather ops I should still be able to keep my oil temps where I want them by simply removing the scat blast tube.

Hope this helps!
 
acroeric said:
I know it is an old thread but I wanted to resurrect it with some data from my PA-11 with a C-90-8. Oil temps were 210 or so on a really hot day (90-95 F) here in NC. I wanted to get the temps a bit lower so when I was at higher density altitudes I would have more margin.

My baffling was not great so I repaired and sealed all that first. Oil temps were not impacted by good baffling and may have been a bit worse. Next, I added a 2" blast tube coming off the left rear baffle (flange fitting was already there) that directed airflow around the accessory case and oil temp probe. This mod dropped my oil temp about 10 degrees. I did see an increase in oil pressure so I know it was not just cooling the probe and the temp check (dipstick) with an infrared temp sensor validated it. The final mod was to install a 2" blast tube from the intake just beneath the spinner (right side) and route that air to the oil tank. This made the biggest difference in a 20 degree drop in oil temps on a hot day.

I am currently running 180 degree oil temps on the hottest of days backed up by a check with the infrared thermometer on the dipstick. The cool thing about this is that for cold weather ops I should still be able to keep my oil temps where I want them by simply removing the scat blast tube.

Hope this helps!
Click to expand...


any chance of seeing a picture of your nose cowl?
 
Only picture I have showing the cowling. It is a stock PA-11 metal cowling as far as I can tell.
IMG_9233 (1).jpg
 

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acroeric said:
I know it is an old thread but I wanted to resurrect it with some data from my PA-11 with a C-90-8. Oil temps were 210 or so on a really hot day (90-95 F) here in NC. I wanted to get the temps a bit lower so when I was at higher density altitudes I would have more margin.

My baffling was not great so I repaired and sealed all that first. Oil temps were not impacted by good baffling and may have been a bit worse. Next, I added a 2" blast tube coming off the left rear baffle (flange fitting was already there) that directed airflow around the accessory case and oil temp probe. This mod dropped my oil temp about 10 degrees. I did see an increase in oil pressure so I know it was not just cooling the probe and the temp check (dipstick) with an infrared temp sensor validated it. The final mod was to install a 2" blast tube from the intake just beneath the spinner (right side) and route that air to the oil tank. This made the biggest difference in a 20 degree drop in oil temps on a hot day.

I am currently running 180 degree oil temps on the hottest of days backed up by a check with the infrared thermometer on the dipstick. The cool thing about this is that for cold weather ops I should still be able to keep my oil temps where I want them by simply removing the scat blast tube.

Hope this helps!
Click to expand...


You have any pictures of this blast tube set up?
 
Jake I just added it to mine, haven't flown it yet

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PXL_20220724_222845512.jpg

Glenn
 

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