4d56 blow by but good compression

[wildplumdx]

so my 4d56 has massive blow by as much as the dipstick pops up and if you take the oil cap off it sounds almost like a car exhaust spiting oil etc, but i have 420psi over all cylinders at 10 cranks? and the factory specs i could find say 384psi but not sure what cranks...
i have more compression than i should

[Swamped]

No idea about the mitsi motors (least thats what I think I remember this is )
but...
Have you got a blocked crank case breather? Wouldn't take much to lift the dipstick out if thats the case. And I've not run a motor without the oil cap on haha. makes a mess but you could be hearing poor valve clearances or similar with the lid off? Could see what a top tune did for it?

If you can't figure it out a leak down test may give you more info.