C

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RV6A First flight went well but we have hot CHT,s . I have a H2AD in the plane and had to run at 1900 RPM to keep the temps down. Here the configuration:

? 1900 RPM
? 3 cylinders run about 390 Deg
? #3 cylinder running about 425 Deg
? Airspeed about 110 ? 120
? Oil temp about 150 Deg
? EGT,s all running about 1375 ? 1425 ( Was not watching these too close, kind of fixated on CHT,s)

If I added power the CHT,s would start to climb. On climb out the hottest cylinder got to 475 ? 480. The probes all have been checked at 212 Deg / boiling water.

Any suggestions would be helpful. I am planning on making a plate to cover about half + of the oil cooler but I had duck tape over part of it during flight and it did not seem to make much difference. I have the large 9 row cooler as I am hoping to move to Florida in the future and figured I will need the extra cooling?

Thank all

John
 
John,
I?ll assume you have a fresh overhaul or top on your engine?
Do all the usual stuff? check baffle seals, make sure your inter-cylinder baffles are installed, I guess also make sure you don?t have casting flashing between the fins.
Check your carburetor? is it running lean? Can you lean it on the ground at a medium power setting?
If all checks well you might want to open up the dimension from the bottom of the firewall to the bottom opening of the cowling. Cut the lower center of the bottom cowl off 2 inches forward at the bottom. I just talked with Scott at Van?s last night about running hot and he agreed this has worked in the past. He also asked me to get back with him if I figured out any other ways to keep the engine running cooler.
It seems Van?s isn?t really on top of the cooling problems. (see the thread on the Caf? Foundation report under the 9 thread)

Can you coax it up to 7000 or 8000 ft and run it wide open? At that altitude you should be able to get 75% power and have lots of cool air in cruise.

Good luck,

Roger
 
You didn't say anything about the OAT. Even so, your cylinders are too hot. First and most likely culprit is poor baffle seals. It doesn't take much of a hole to let quite a bit of air out. Check your seals around the intakes too.
 
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