so ive had some oil on the top of my #4 piston for a while now (looks wet through the spark plug hole). there is no oil on the spark plug itself. the other cylinders are dry

the engine is a 84.5mm benson sleeved gsr at 9.8:1 static compression.
compression tests are all very even 220-225psi every cylinder, and all leakdowns are 8-10%, coming through the rings.

ptw is at .0045 and ring gaps are .024 top and .026 2nd ring. oil rings are within spec. this is with cp shelf pistons. the car runs great, blowby is minimal at about a shot glass worth for every 1/4 mile pass. the tune is pretty conservative, pump gas afr 11.4 to about 11.8 and the plugs show no signs of detonation. i do have a little audible piston noise starting a minute or so after startup and it goes away when my oil reaches about 150 f. oil and coolant consumption is not noticeable off the dipstick or out of the overflow for coolant.


id like to say i just have a bad valveseal, but im just trying to get opinions before i rip it apart

 

is it me or does that compression seem high for those pistons? Aftermarket valves? How thick of an oil are you using? I think you may be right with the valve seal hypothesis.....

 

Ah seems good. For comparison my stock ls motor is between 190 and 200.

Using conventional castrol 10w-40. I change it honestly like every 1500 miles

 

every gauge seems to put out different numbers thats why we look for consistency. Maybe valve seals? I would say maybe the ring gaps lined up but you said its been wet for a while which would make me think valve seals.