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Oil Cooler Questions

SeanB

Well Known Member
Hey everyone,

I am getting ready to purchase the baffling kit and oil cooler mount for my Aerosport IO-375 (low compression, 195 hp) RV7 project. I've already purchased the RV Bits Carbon Plenum. Looking at the archives provides plenty of variety with respect to brand, mounting ideas, mods, etc. for the oil cooler. I read some have even mounted to the firewall (maybe with the -10 mount ?).

Looking for pics, suggestions on brand, number of rows, etc. How difficult it was to install something "non-factory" would also be appreciated. What worked for you? Would you do it the same way again?

Thinking about using Van's shutter to warm it up in the Colorado winters, but want to keep her cool the rest of the time.

Thanks!
 
Oil cooler

I mounted a 17 row ( Robinson R22) oil cooler off the fire wall 5"x6" oval duct feeding it , works perfect in Florida .( can email you pics )
 
I used a Motronic. It is inexpensive, well built and light. I think that I got a 7 or 8 row and it keeps my O-320 (160 HP) temps under 190 in 90* + ambient temps. These units are much smaller and lighter than the aviation versions as they are more efficient. It is mounted on the baffling. This is why I like the light weight, it helps keep it from destroying the baffling. Although I did substantially reinforce that corner of the baffling.

Larry
 
Thanks for the responses so far.

I hadn't heard of the Robinson R-22 coolers being utilized. Already two responses indicating that unit. I'll look into it.

I kind of like the idea of the RV-10 mount to the firewall. Seems it will be out of the way and solid. I assume you integrate some of the angle bracing of the firewall for support.

The pictures and build sites are very helpful. Thanks again!

Any others?
 
Nice pics of that firewall mount

Great pics of that firewall mount, however, wont that be pretty hot for the pilot on warm days?

Dave
 
My O-360 started life with the "stock" Niagara oil cooler mounted on the baffle behind cylinder #4 and I quickly found it wasn't up to the task.

I ordered a Stewart Warner 10599R oil cooler. The reason was this is very close to the same size as the Niagara it was replacing.

I did have to widen the platenuts up, maybe an 1/8 of an inch. I also had to add a stiffener to the baffle as the original baffles cracked. This is a picture of what I'm talking about.

A friend installed his oil cooler on his firewall and ran a 3" scat tubing to it. That didn't work out very well so we made this transition for 4" scat tubing and his cooling problems went away.
 
My O-360 started life with the "stock" Niagara oil cooler mounted on the baffle behind cylinder #4 and I quickly found it wasn't up to the task.

I ordered a Stewart Warner 10599R oil cooler. The reason was this is very close to the same size as the Niagara it was replacing.
Hi Bill-
Do you have any sense of how much your 10599R might have lowered your oil temps?
 
If you have oil squirters on your IO-375, be prepared for oil temps as much as 20F higher than an engine without them.

I have IO375, low compression, oil squirters, RV10 cooler mount and use 4" scat to feed it. SW8432R oil cooler.

Oil temperatures are still a problem and I have checked ALL of the normal things to check.

Now adding second cooler to see if things get under better control.

My temps will not stabilize at 220F at best power setting but I can keep it under 200F with my cowl flaps closed running lean of peak. I am hoping I can run at ROP best power settings when I want to with the second cooler.

Will post results after testing with second cooler.

Randall in Sedona
 
FW mount cooler is cooler

Great pics of that firewall mount, however, wont that be pretty hot for the pilot on warm days?

Dave

Having the FW mount for an oil cooler does nothing that wouldn't happen anyway. The engine side of the FW is essentially exposed to the same air temps because it is the same air volume. In fact, it could be argued that the air mass coming into the mount is air that entered the front of the cowl, into a SCAT tube and into the mount before passing thru the cooler, or cylinder fins. Thus, it may be at a lower temp in the mount plenum then air that would pass thru the cooler on a baffle mounted arrangement before hitting the FW.
 
Motronic oil cooler

Larry/LR172,
Out of interest do you have the part number for the oil cooler you used?
Thanks.
 
My temps will not stabilize at 220F at best power setting but I can keep it under 200F with my cowl flaps closed running lean of peak. I am hoping I can run at ROP best power settings when I want to with the second cooler.

Will post results after testing with second cooler.

Randy, I know you're pulling your hair out at this point, but gosh, I've never heard of anyone needing two coolers on a non-turbo.

There's something whacked in that installation. It's just not been found yet.

Hey, early on I recall you mentioned measuring case pressure. It was quite high under some conditions; do I remember 4~5 inches H2O? You were still in break-in, so it was discounted at the time. Have you measured lately? Excessive blow-by is a huge factor in high oil temperature.

A friend installed his oil cooler on his firewall and ran a 3" scat tubing to it. That didn't work out very well so we made this transition for 4" scat tubing and his cooling problems went away.

Hear, hear! A common 8432 or 10599 has a finned face area about, what, 22 ~ 24 sq inches? If you mounted it on the baffle, you would cut a 20 ~ 24 sq in hole. So why would anyone think they can feed the same cooler through a 3"D ribbed hose with a nominal flow area of 7 sq in?
 
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Hear, hear! A common 8432 or 10599 has a finned face area about, what, 22 ~ 24 sq inches? If you mounted it on the baffle, you would cut a 20 ~ 24 sq in hole. So why would anyone think they can feed the same cooler through a 3"D ribbed hose with a nominal flow area of 7 sq in?

One of his problems is that he used one of these on his oil cooler, which effectively gives him only 7" of cooling area (Area = 3.14?1.5?1.5). By adding the larger tubing and making smooth transition to the entire face of the cooler the air slows down and passes through the entire cooler, not just seven inches of it.
 
Dan,

You probably right about something whacked in my install and adding the second cooler is kind of extreme. Most of the experts I talk to tell me not to do this, it should not be needed etc.

I measured 10" to 12" WC differential across the engine and nearly the same at the cooler itself, which puts it high on the efficiency chart from Pacific Oil Coolers.

In my case, I had quite a bit of the stuff laying around for adding the second cooler so the job has not been very difficult, and I will be happy one day to take it back off and set it on the shelf after finding the real problem:)

Complexity wise, I have added two more flare connections to the oil system, had Tom make up some nice -8 lines, and I had a good space left on the pass side to mount it. If I put in one of those life po batteries along with it I can claim it lightened the airframe:)

I will also be happy if I have excess oil cooling capacity. Maybe I will remove it in the winter and put it back on in the summer..

ECI tech tells me not to worry about oil and CHT temps that I have experienced and just fly within the Lyc. recommended redline temps.

At this point the money and weight cost will be worth it to me if it can even temporarily solve the problem. I decided to do this after talking to others that have done the same thing with good results. We wil see how it does in a few days.

Compression checked good with normal blowby past the rings. All in the mid to high 70s, checked cold.

Randall in Sedona.
 
FWIW - was the Oil Temp reading ever checked against a calibrated instrument ? No mention of that in the posts & should be first port of call, if not done already. I know of a situation where Oil Temps were supposed to be too high & the guy went through the same dual cooler route, end result was the EMS software had a bug.

Jake J
 
Another vote for the Stewart Warner. I put squirters on my second RV, big mistake I won't make again however the Stewart Warner brought so the temps down.
 
I have 290 hours on my AeroSport IO-375 without piston squirters on my 7A. I used the Van's stock baffling, cowl, and cooler mounted behind the #4 cylinder. I couldn't keep the oil warm until I blocked most of the cooler off with aluminum tape. I leave about 3 square inches of cooler exposed in winter, and 4 for Canadian summer to obtain 180-190 degree oil temp. Oil did hit 210 climbing out of Oshkosh this year. A flow shutter would be a good addition for me.
 
Angle valve 360, 10:1 Pistons, Pmags, SW8432R mounted on baffle behind #4. Despite the piston squirters and high compression, my oil temps are low...often too low. I install a shutter in the fall to keep temps up. The key is a tight baffle system and a good cooler mounted with plenty of air flow....note I said good air flow, not what someone on VAF you've never met and who has questionable engineering skill tells you is good enough air flow. I fly in Florida quite a bit. Mid summer, Florida Vy climb to 17500, no issues with cooling and I mean none. Tight baffles are the key (I have a plenum) ....and air flow through the cooler. If you have a 3" scat tube feeding an oil cooler....you're not pointing your nose up very often.

I'll be reducing cooling flow over the winter. I'm running too cold, while racing....wide open. I'll say it again.....tight, well sealed baffles. If you don't feel like you are seriously anal retentive when it comes to baffle seals, you're not doing nearly enough. That last 10%.....is everything.

FYI, I'll never own a lycoming without squirters.
 
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