RV-8 oil temp problem

pierre smith · #1 09-04-2006, 07:17 AM

Hi everybody,
A friend of mine has a beautiful 8 with a hard-to-figure oil temp problem. He now has a 13 row oil cooler for his angle valve IO-360 mounted on the firewall. He has also gone to 4" scat tubing and the vernatherm's been checked and works fine. He has a Sam James cowl and a Whirlwind composite prop. He used some wetsuit pants legs to connect the inlet rings to the plenum but they are somewhat constricted in the middle and smaller than the inlet openings by about a third. When I pressed on them, they easily expanded but I'm not sure that they do so in flight.

His temp on a 90 degree day stops at 217F which is not bad but could it be the intake restriction? What do you guys think? His oil lines are mounted on the upper rear of the case and I believe there's another possible location in the center of the case but it's not very accessible now. Could it be a plumbing problem?
Thanks in advance,

Kyle Boatright · #2 09-04-2006, 08:05 AM

I'd look at that wetsuit material. My guess is that it takes more airpressure than the intake/plenum system is generating in order to expand that material to full size. In addition, there is no way of predicting how the material will deform, so you may not have a nice, smooth, circular duct if the material does expand.

Maybe your friend can find a substitute material, or can find a larger diameter section from a wetsuit pants leg.

How many hours does your friend have on the engine? If it is a brand new engine with <100 hours, it may still be in breakin mode, and have slightly high oil temperatures.

Other thoughts would be to switch to a 4.5" or 5" SCAT tube and to make sure he is using a Stewart Warner oil cooler, which is more efficient.

Brian Denk · #3 09-04-2006, 08:06 AM

217 deg. F isn't too bad really, especially on a hot day. Doesn't seem to be anything wrong with the cooler, inlet and hose configurations. I just changed out my oil temp gauge (removed old Isspro and installed new Van's gauge) and my temps show somewhat lower than I was used to. So, calibration is always worth checking with any instrumentation setup so you don't end up chasing a problem that isn't really there.

dan · #4 09-04-2006, 09:07 AM

Quote:

Originally Posted by Brian Denk

217 deg. F isn't too bad really, especially on a hot day.

Ditto...if it peaks at 217F in a climb, but then drops back down, then he's doing juuust fine IMHO. I've seen worse...

osxuser · #5 09-04-2006, 09:54 AM

How does the air exit the cooler?

striker · #6 09-04-2006, 08:39 PM

Pierre:
I have a new ECI IO-360 in a 6A using the Holy Cowl by Sam and Will James. They do sell the correct material for the intake rings- very reasonable price and it works great. My oil temps were 220-230 degrees for the first 60 hours and then I switched to Exxon Elite and they have dropped to 180-190 degrees. Our CHT's are 340-350 in max climb and 315-320 in cruise. Plane based in Atlanta.

Pete Joslin
RV6-A

pierre smith · #7 09-05-2006, 05:22 AM

Hi guys and thanks, Pete,
I was in Atlanta yesterday giving some transition at McCollum and then over to Cartersville. Where is your plane located Pete?
Regards,

striker · #8 09-05-2006, 07:28 AM

Pierre:
I have been based at Winder- just moved to Lawrenceville this weekend.

Pete Joslin

DanH · #9 09-05-2006, 09:00 AM

Pierre,
If I recall correctly I used 5" scat when I plumbed a remote cooler on an IO360. It worked very well. Big difference in area between 4" and 5"....in excess of 50% more. Also used a molded glass plenum at the cooler.

Dan

pierre smith · #10 09-05-2006, 02:03 PM

Thanks Dan,
The amazing thing is that we have a 7 row cheapy cooler from Spruce in our 6A with an 0-360 and a homegrown overhaul and only two inch scat to the firewall mounted cooler! Yesterday I ran it pretty hard coming back from Atlanta at 7500 and 2650 RPMs (203 TAS) and it stayed around 195F all the way. Are the angle valve IO-360s difficult to cool as a rule?
Regards,