what do you guys think about this?

ive got oil on the top of one of my pistons as seen through the spark plug hole.
the spark plug is clean no oil
the intake and exhaust ports dont have any oily crud build up
compression is 225psi, all my cyls are between 220 and 225 on a 10:1 engine
leakdown is 8%, all my leakdowns are 6-10%. it is a 500hp engine so my piston to wall and ring gaps are on the big side. all lost air is going into the crankcase as i hear the pitch change when i take off the oil fill cap/dipstick.

what ya think? valveseals? is there any way its left over oil from assembly i might have gotten in there? engine has 3500 miles

 

More and likely the valveseals are leaking since the oil in on top of the piston. The oil use in the build should have been burned of now or after ur first all change. Was all four piston were around the same psi. Cuz more and likely the one with the oil should have been higher than then other due to oil.

 

all 4 cylinders were within 5 psi compression. it wasnt a puddle of oil by any means, but you could see that it was wet like you wiped the piston with a oily rag. that cylinder did have a tad more carbon buildup in it

 

It can be fuel your seeing. Maybe too much fuel in that cylinder. Is it burning oil??
Is this the engine you just had apart??