crank case pressure.. help please

[AE101LEV]

I am trying to pinpoint why my 4agze is blowing the dipstick out of the hole at high rpm and blowing oil everywhere..

basically I have noticed a difference in oil pressure that has increased lately and only in the last couple of days it has started to shoot the dipstick out and put a bit of oil in my bay

so would be keen on what you think I should be thinkn about

I have allready checked the cam cover breather and thats not blocked and it leads into the intake so its got room to breath.

there are 2 things I am thinkn baring in mind my motor was rebuilt from teh ground up 29 thousand km's ago. either

premature failure of the compression ring
a clogged oil filter

any other ideas.. i havent replaced the oil filter for a bit as i just havnt had the time working 75 hours a week. the oil has been replaced but not the filter for about 15K i would say.. i know really bad and slack of me but i really havnt had the time to do it.

[LeeRoy]

Do a compression and leakdown test.

Put a spring on the dipstick?