what is hot oil temp

Bob Ed · #1 05-27-2008, 11:25 AM

i fly a rv10 w/ an io 540 new w/ 60 hrs. oil temps of 225 low of 190 with all adjustments i can think of to lower the temps. plan on putting louvers on sides of lower cowl have . will that solve it. i have 3"hose to oil cooler. any thoughts? what are good temps?

Mel · #2 05-27-2008, 11:29 AM

I like to see oil temps around 190-200F. 210-220 on climb out is not a problem. I consider 180F about minimum.

Bob Ed · #3 05-27-2008, 11:36 AM

when i try to lean for better fuel numbers the temp goes up as well as when i try to exceed 75% power at lower altitudes.

jetjok · #4 05-27-2008, 11:57 AM

I agree with Mel Asberry on his numbers. The following is copied from Lycoming SI 1094D item 9.

9. For maximum service life, maintain the following recommended limits for continuous operation:
(a) Engine power setting - 65% of rated or less.
(b) Cylinder head temperature - 400°F. or below.
(c) Oil temperature - 165°F. - 220°F.
(d) Turbine inlet temperature - maintain 100°F. on rich side of maximum allowable.

While it mentions TIT, this bulletin is applicable to all Lycoming horizontally opposed engines. This following is my opinion, but once again I agree with Mel; The minimum oil temp is indeed 165F, but you need to be at 180F+ to assure alleviation of condensation. Once again..my opinion only
Good Luck!

ScottSchmidt · #5 05-27-2008, 12:15 PM

Hi Bob, on hot days I typically climb out at 105 knots and that keeps my oil temps below 215.
What are your CHT's? I would get my CHT's up to 410 sometimes on climb out but I have sealed up my baffles much more diligently and I rarely see 400 now.
With 60 hours you should start to see the temps go down.
Read this page on Tim's site and it will show you some pictures and ideas. I wasnt' a believer that it would make one difference but I was amazed. Once you get the CHT's to drop the oil temps follow right along with it.

http://www.myrv10.com/N104CD/mainten...022/index.html

Try this first before adding louvers. I was going to add them as well but after working with the baffles there is no need. I have climbed out at Palm Springs on a 100 degree day all the way up to 11,500 and didn't see 210 oil or 400 CHT climbing at 105 knots.

Good luck.

db1yg · #6 05-27-2008, 12:59 PM

Hi Bob,

As has been said your temps should go down some as the engine gets more time on it. However, you mention that you only have a 3" tube supplying air to the oil cooler--I had a 3" on my 0360 powered RV9a (firewall mounted cooler) and it was inadequate. I went to 4" sceet tube (smoother inside than scat) and saw a nice improvement.

You folks flying RV10s, is a 3" scat normal??? Doesn't it use a larger cooler than the 4 banger RVs? If so wouldn't a 4" scat be minimal for air to the cooler--maybe a 5" even better??

Cheers,

db

Radomir · #7 05-27-2008, 01:15 PM

RV-10 uses 4" SCAT... Dave, when I upsized I used RV-10 parts (flange for the baffle...). I'm surprised that the 3" is working even that good on the -10

Bob Ed · #8 05-27-2008, 03:47 PM

the scat tube is actually 4" as i now remember. the cht does not exceed 400 in most flight configs including climbs.i find it curious that the oil goes too high while the cht and egt does not. i have been climbing at 95kts. but the 105 sound like a better speed.i will hold off on the louvers on the hope that the numbers will improve. but it is hot and humid now and i dont want to hurt this beautiful engine.

leeschaumberg · #9 05-27-2008, 04:28 PM

As you know use 4" instead of 3" scat for cooler supply. Before putting a lot of work in your plane make sure the tempurature indicators are accurate.Oil temperature is easy. Take only the indicator bulb and put it in boiling water. Water boils at 212 deg at sea level. As the altitude goes up the temperature goes down. Good Luck

rvbuilder2002 · #10 05-27-2008, 05:46 PM

Quote:

Originally Posted by Bob Ed

i find it curious that the oil goes too high while the cht and egt does not.

It is entirely possible to have high oil temps with all other temps looking more normal.
One cause, is not getting a good cyl./ring break in which allows more combustion gas blow by than normal. The hot combustion gases blow past the rings into the crank case area and add more heat to the oil than normal. This can easily cause temp problems in hotter weather.

Is there evidence of blow by out of your crank case breather tube?
After 60 hours, your rings should be pretty well broken in and your belly should be relatively clean of any amount of oil. Give it a good cleaning and see what it looks like after 10 - 15 hours. If you find oil, you may have to try for another ring break-in.