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  #1  
Old 03-31-2017, 03:11 PM
Timberwolf Timberwolf is offline
 
Join Date: Nov 2016
Location: Navarre, FL
Posts: 385
Default High oil temps

https://drive.google.com/file/d/0B_6...w?usp=drivesdk Hey guys I've searched with no avail that explains why I gave high oil temps where others don't. -6 IO-360 angle valve, cooler mounted on firewall (brand new 9 row aero classic) pulling air from behind #3 cylinder. Verified oil temp probe reading correctly. Temps shoot straight up to 220 and stay there. Oil cooler is hot and checked at 195 soon after landing with IR gun. The aircraft is new to me and previous owner moved cooler in hopes that it would fix it. Verrnatherm has not been checked but it is my understanding that if the cooler is that hot it is doing its job. Only thing I can think is lack of airflow at the cooler, but not sure got to rectify that

Any and all ideas are welcome as we would like to make it down to sun n fun if I can get this one figured out.

Last edited by Timberwolf : 03-31-2017 at 04:03 PM.
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  #2  
Old 03-31-2017, 04:18 PM
flyinga flyinga is offline
 
Join Date: Dec 2007
Location: Fredericksburg, TX
Posts: 662
Default

I have basically the same setup as you have in my RV8. My temps do not run as high as yours are. You didn't say what type aircraft you have. If you have an "A" model perhaps you need to enlarge your ram air exit.

Good luck!
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  #3  
Old 03-31-2017, 05:36 PM
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Carl Froehlich Carl Froehlich is offline
 
Join Date: Dec 2007
Location: Dogwood Airpark (VA42)
Posts: 2,597
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I offer the oil cooler is mounted wrong. You have air coming in forced to change direction, then exiting the cooler again forced to change directions.

I'd first mount the cooler horizontal, and perpendicular to the firewall. The air then comes in straight and leaves straight. Remake the cooler to SCAT hose adapter to make the transition air flow as straight as possible.

It is hard to tell from your photo, but it looks like the scat hose is not a full 3" in diameter. If not, it needs to be.

Try those first, then as a last step try the 2006X cooler: http://www.aircraftspruce.com/catalo...sOilCooler.php

Carl
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  #4  
Old 03-31-2017, 07:36 PM
Michael Henning Michael Henning is offline
 
Join Date: Jun 2011
Location: Nashua, NH
Posts: 536
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Just looking at the picture, it looks like the cooler is mounted close to the firewall and may be restricting the exit airflow.
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  #5  
Old 03-31-2017, 07:49 PM
BillL BillL is offline
 
Join Date: Sep 2007
Location: Central IL
Posts: 5,516
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With little information to go on, it sounds like the temp levels off almost regardless of the ambient? If so the vernatherm is working, but could be off. The sensor could be off. The air supply may be leaking at the face of the cooler.

It could also be aggravated by poor pressure differential between upper and lower plenums. And . . advanced timing with oil coming jets.

What size is the air supply?
Is the inlet to the air supply rounded - like 1/2 in radius?
Is the end of the diffuser sealed good to the face of the cooler? There should be no leaks. You can use a leaf blower on the supply and feel for leaks.

What is the ambient at 220f? Does it rise with ambient?

You could have some issue with sensing. A surface temp can be way off what the real temps are. Measuring the exit oil temp with a thermocouple would help eliminate that possibility.

The field will need to be narrowed for any definitive help. Since 220 is not that bad, you might fly to SnF and get some RVers to look at the system to see if there are any obvious baffling (or other) issues.

And why does my post indicate 7:49 PM when I am at either 8:49 (home base) or 9:49 PM (actual local - also on current PC)??
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Last edited by BillL : 03-31-2017 at 07:52 PM.
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  #6  
Old 03-31-2017, 07:57 PM
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N941WR N941WR is offline
 
Join Date: Jan 2005
Location: SC
Posts: 12,887
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Do you know if your engine had oil squirters on the bottom of your pistons?

What are your CHT's running?
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  #7  
Old 03-31-2017, 07:58 PM
Reformed SeaSnake Reformed SeaSnake is offline
 
Join Date: Nov 2016
Location: Beaverton
Posts: 50
Default More Info?

Sorry if any of this is obvious, but;

What are your CHT's like? Are #2 and #4 running particularly cool?
Are you sure the baffles are well sealed?
You mention oil temp goes to 220 and stays there. does oil temp really stay constant or does it vary somewhat with OAT and CHT?
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  #8  
Old 03-31-2017, 08:13 PM
jrs14855 jrs14855 is offline
 
Join Date: Apr 2008
Location: Lake Havasu City AZ
Posts: 2,393
Default Oil Temp

3" duct is inadequate. Start with 4" and if that doesn't bring it down enough change the path of the intake and exit air.
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  #9  
Old 04-01-2017, 09:52 AM
Timberwolf Timberwolf is offline
 
Join Date: Nov 2016
Location: Navarre, FL
Posts: 385
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Hey guys thanks for all of the replies. Back at a computer so I can give a little more detail. Temp probe verified with boiling water, new baffling material and all seems well sealed. Ducting is 3" scat right into the cooler. Ducting all to the cooler and the cooler face is well sealed with no leaks. It attaches to the back of the baffling with a tig welded aluminum tube to a flat plate, not exactly contoured. Engine does have oil jets and timing is verified at 20*. Looking at the chart for the X-series coolers, it looks like they recommend no less than a 13 row for oil squirters. I only have a EI scanning egt/cht gauge so not able to log the temps, but I do believe they all evened out one I powered back at cruise. I haven't had a chance to really get up and check with different temps, but all this was around 80 degress OAT. If I remember correctly I want to say my CHT on my #1 was under 290 with everything else leveling out around 340. I'll try to get a flight in today to verify.

Some observations...
This plane doesn't have the front baffle right behind the ring gear. I just cut one out with the plasma and baffling material will be here Monday. Though some air could be escaping to the lower cowl from here, I have it pretty well sealed up with RTV.

Looking at a buddies RV-7 I see he has the ramps on his top cowl. I suspect to speed the air past the front cylinders and make it all the way to the rear cylinders to prevent this very issue.

I've read where others have had some of the same issues and people have put on a firewall cooler as well as the one behind the #4 cyl. I have the previous owner shipping me the 7 row that went behind #4 in hopes that I could run them in series to get the temps down until I can fix it correctly

https://drive.google.com/open?id=0B_...C1JZDFjSWNDVlU
https://drive.google.com/open?id=0B_...jhuYTdHcTFUaWM
https://drive.google.com/open?id=0B_...UxxNnlRSjMyVmM
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  #10  
Old 04-01-2017, 11:50 AM
Robb Robb is offline
 
Join Date: Sep 2015
Location: Nevada City Ca
Posts: 198
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I had issues as well with the stock cooler and 195 hp. I switched to sn 8001599 cooler and a 4 inch scat tube. It's a lot better now but still have to watch it on climb out. I have piston squirters and a Sam James plenum so it's a lot different
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