FIRST FLIGHT....BUT !!!

[rv7guy2]

RV-7 C-GCPD took to the air last Thursday June 12 from CNM4 in Ontario.(Stratford Ontario) following a 4 1/2 month paint job and a lost paper work issue (on their end, not mine) Flew great except for one thing..a high oil temperature. My check pilot and myself elected to land after only .2 in the air. We took off under full power and climbed out to 4 thousand feet ASL. We pulled power back to 25 square during the climb however the oil rose to 230 F and was on it's way to 240 F when we pulled power and came back down. The engine is a newbuild 10-360 with 9.25 pistons. The prop is a Hatzell blended airfoil. The cooler is a standard Van's unit, an 8 tube Niagara Thermal as suppled in the FWF kit and is mounted in the recommended position on the back of the bafffle of Cyl #4. On Saturday I pulled the oil temp sensor (Dynon supplied for the EMS-120) and tested it using the boiling water test and the displayed temp seemed to be OK. The on-field mechanic came over and checked out my instlation and he says it should be fine. He believes the cooler is big enough and should be getting plenty of air.
During my short flight the cylinder head temps seemed to be OK and did not reach redline. The EGT did not redline either.
Do I go for it again but reduce power to 24 square rather than 25 square? Use a much more shallow climb out and stay lower to allow more air through the cooler?
What do you guys think is the absolute highest sustained oil temperature I can maintain while my expensive engine breaks-in?
It's a beautiful day to fly here today, but I don't want to cook my engine .

Dave

 

[Kyle Boatright]

Oil temperature has two impacts - it reduces the viscosity of the oil so you get lower oil pressure, also it accelerates the chemical degradation of the oil.

As long as your oil pressure was OK and assuming you're planning on an oil change at 5 or 10 hours anyway, I would go ahead and fly with the 240 degree oil temperature or even 245-250. At this time, your engine is not in normal operating conditions - it is in the initial stages of break-in, so the normal operating limits may not be 100% relevant.

In fact, there is a very good chance that the high oil temperature is due to your engine being in a break-in period. Until your rings seat, there will be higher than normal blow-by, which increases oil temperatures. Also, your engine is in what I call the self-machining phase where all the moving components are grinding off any irregularities left from the machining process. That creates extra heat as well.

 

[Carr]

High oil temp

Dave

What climb speed did you use?

What oil weight 80 or 100?

Do you have a plenum or do you use the cowl and rubber?

What was the OAT/

All these things will affect your oil temp.

Bryan Carr

 

[Geoff]

Get a better cooler

RV-7 C-GCPD took to the air last Thursday June 12 from CNM4 in Ontario.(Stratford Ontario) following a 4 1/2 month paint job and a lost paper work issue (on their end, not mine) Flew great except for one thing..a high oil temperature. My check pilot and myself elected to land after only .2 in the air. We took off under full power and climbed out to 4 thousand feet ASL. We pulled power back to 25 square during the climb however the oil rose to 230 F and was on it's way to 240 F when we pulled power and came back down. The engine is a newbuild 10-360 with 9.25 pistons. The prop is a Hatzell blended airfoil. The cooler is a standard Van's unit, an 8 tube Niagara Thermal as suppled in the FWF kit and is mounted in the recommended position on the back of the bafffle of Cyl #4. On Saturday I pulled the oil temp sensor (Dynon supplied for the EMS-120) and tested it using the boiling water test and the displayed temp seemed to be OK. The on-field mechanic came over and checked out my instlation and he says it should be fine. He believes the cooler is big enough and should be getting plenty of air.
During my short flight the cylinder head temps seemed to be OK and did not reach redline. The EGT did not redline either.
Do I go for it again but reduce power to 24 square rather than 25 square? Use a much more shallow climb out and stay lower to allow more air through the cooler?
What do you guys think is the absolute highest sustained oil temperature I can maintain while my expensive engine breaks-in?
It's a beautiful day to fly here today, but I don't want to cook my engine .

Dave

There are numerous threads here about that Niagra 20002A cooler and its inability to cool the oil on an IO-360, especially one that's putting out more than 180 HP due to your piston selection. A few people with O-360s and standard pistons have no problems with them, but a lot of people with IO-360s and/or high compression pistons do have issues.

Switch to a Stewart Warner 8406R (same form factor as the Niagra 20002A so it's a direct replacement) for a 10-15 degree F drop in oil temperature. Better yet, switch to a wider cooler (of any brand) for an even larger drop -- but this will require reworking the baffle.

www.rvproject.com has a nice writeup about the oil cooler issues.

 

[Webhead]

Vernatherm

This site may help.

http://www.sacskyranch.com/eng18.htm

 

[RV7Guy]

Stewart Warner

That seems very high even for a new engine. I would suggest a few things before "breaking the glass."

1) In a dark hangar put a light source on top of your engine with the top cowl in place. This will allow you to see every place that light is getting through the engine and baffling. Seal them with high temp silicone.

2) Check the rubber baffling for lack of seal. Same method as above.

3) Pull your oil temp probe and put in boiling water and see what it reads. Mine was 5 degrees cooler than reality.

These are starting places. I am running a Stewart Warner 8432R in my 7 with ECI IO360. In the brutal AZ heat I rarely hit 210, even on the ground. In cruise I am at 180 and as low as 170 with altitude.

You also didn't mention if you have your gear leg fairings and wheel pants on. These will have an affect as well.

Keep us posted.