912uls with temp problem

[lakeflyer]

I just bought a beautiful kitfox 4-1200 with a 912uls 100hp it has 6 hours on it, the builder did a wonderful job, it looks like a show plane, durring the test flights the oil temp rises to over 250- 260. the builder thinks it could be the spinner /prop combo? The spinner is 8 1/2" and prop is a 3 bladed GSC. Cylinder head temp is normal The one thing I see which might contribute to the over heating problem is the spacing between round cowl and the airplane, I wonder if there might be a correct spacing for the air to exit ? does anyone have any ideas? lakeflyer

[cap01]

My model IV round cowl is tight against the boot cowl and I've never had a problem. You didn't mention if there is a cooler and thermostat installed

[lakeflyer]

Yes there is the oil cooler just under the spinner, I suspect it does have a thermostat, where would it be located?

[Geowitz]

I just bought a beautiful kitfox 4-1200 with a 912uls 100hp it has 6 hours on it

Do you mean space between the round cowl and the main cowl or do you mean between the main cowl and the actual airplane.

If you are asking about the space between the main cowl and the airframe as in the outlet on the bottom of the cowl there should be a reasonably sized opening. I've always been told twice as much outlet as inlet, but that's not always possible. You may have air ramming into the cowling, but if it has no where to go it won't help you oil cooler.

[lakeflyer]

my space at the bottom of the cowl is maybe 1/4'' it is 3/4'' on the top

[Geowitz]

Please be more specific. What spacing are you talking/concerned about?

[lakeflyer]

Im looking at the spacing behind the round cowl where it attaches to the plane,thanks for helping me to resolve this problem

[Geowitz]

There a four parts to your cowling. The two rings up front, top and bottom and two "boot" cowling halves. There should be a small space about what you've mentioned in between the actual round halves and the boot cowling. That space is not really a major cooling air exit. The bottom of the boot cowling is the major source of cooling air exit.

Perhaps the oil lines are not routed to the correct connections?

[HighWing]

Interesting problem. The Model IV with oil cooler usually has temps in the normal range to slightly on the cool side. I don't think it is the spinner - that is the same size I run. A friend has a Model IV with a two piece cowl with the two ring cowls bonded to the main cowl top and bottom with no heat problems. The spacing Geowitz is talking about is the opening below and to the pilot side of the lower main cowl. Mine is 2.75X 13 inches. What does the oil pressure look like. It usually is right around 70 psi. at start up. You mention that the cylinder head temp (coolant) is normal. If that is the case, the first thing I think I would do is check the temp sender. Drop it in some boiling water and see if the oil temp registers at 212°.
Lowell

[Geowitz]

You mention that the cylinder head temp (coolant) is normal. If that is the case, the first thing I think I would do is check the temp sender. Drop it in some boiling water and see if the oil temp registers at 212°.
Lowell

Sometimes I want to smack myself in the head. I'm always telling people to check the simple things first, but I completely forgot to even think about the sensor being wrong. Lowell is right. Check that first as your problem is not typical at all. As long as the builder constructed things generally they way they should be you should have no cooling issues what so ever.

[Slyfox]

might have the wrong sensor. when I changed my engine the new sensor on the engine didn't jive with the guage, read to high, just a thought.

[Dorsal]

Yes, the sensor and the gauge must be matched and can be very sensitive to proper grounding.

[Av8r3400]

I see you are in New Mexico, (NM) on your title.

What was the ambient temperature the day in question and what are your operating parameters (Full throttle RPM, speed, type of fuel, etc.). Were you doing pattern work (full power then power off decent)?

If you are using synthetic oil (Moble1 Racing 4T, Etc.), your oil redline temp is 280°. I often see 230-250° oil temps with no oil cooler in a round cowl during hot weather in Wisconsin (80-90° OAT). This is an acceptable "normal" per the guys at both LEAF and Lockwood for a 912UL or ULs.

[Av8r3400]

Oops, my bad.

You have MN (Minnesota) in your title. :eek:

[lakeflyer]

Thanks all for the great advice, I'll go back to the drawing board. It is hard for me to believe that a plane which seems to be built so well and in detail should have high oil temp issues. The plane looks like an Oshkosh winner, I wish I could take the builder flying just to share the fun on his hard work, it dosen't seem fair. I will take all of the advice to the airport and with help I suspect and hope it will be an easy fix. thanks, dan

[DesertFox4]

Dan, photos of your engine install, coolant radiator and oil cooler might be helpful if it is not just a sender problem. Good luck and check back and let us know if you found a solution or you need more assistance.