Odd oil spot after 45 minutes of flying

[Nukemzzz]

After the 45min test flight a couple of days ago we pulled the cowling and see this oil spot around the exhaust port on the head. It’s baffling me. Where could this have come from?  Head had no oil on when we started it and there is no other oil on anything around this area. Valve cover doesn’t seem to be leaking. I would say the cylinder is burning oil, but how did it get past the gasket?

it’s hard to see in the picture but it’s on the cooling find all the way around the exhaust port and just on this cylinder  maybe a leaking freeze plug I can’t see?  Maybe it’s nothing  seeing what you guys think  

[takair]

Is that #3?  If fresh overhaul, the preservative oils that manage to get everywhere seem to loosen up and end up there.  If it is only number 3, check that the oil pressure regulator isn’t leaking.  The adjustable ones seem to leak the most and hard to stop the dribble.  

[Nukemzzz]

1 hour ago, takair said:

Is that #3?  If fresh overhaul, the preservative oils that manage to get everywhere seem to loosen up and end up there.  If it is only number 3, check that the oil pressure regulator isn’t leaking.  The adjustable ones seem to leak the most and hard to stop the dribble.  

Good advice. I’ll check it out. 

[Rodeo John]

check the push rod tube right above ! Could be a Leakey seal ! I had one last week !