Smoke : Valve seal or piston ring

[F3600]

Hi !
3 month ago my car started to burn a lot of oil .. Well

at idle may car is smoking a litlle

After a 3-4 second load at 4000 RPM when i release the throttle there a very big cloud
of smoke coming out my exhaust.

anyway ive got a compression test and the mechanic was telling me it was one off my piston ring... i have read some webpage and its look like more a valve seals problem but i want your opinions just to be sure.

if i take out my valve cover, can i see the valve seal and see if they need repair ?

one more thing .. i opened my oil feed on the valve cover and it was blowing oil everywhere and there was some Puff of smoke coming out at intermitent interval.

well hope you can help me.. if i cannot do nothing im gonna buy an old ka24E. I want to keep my 240sx its a damn nice car...

cya everyone
thx for the help !

Fred