high crankcase pressure
 

leak down and pressure test all ok-
still have seriously high blowby - could it be my oil pump is defective-
i had a leak at the back of my engine - coming from a plate with 4 bolts in it - i took the plate off and inside was a metal rod - looks like a hydraulic something or other covered in oil - please advise on what it is

Have you changed your PCV system, including all hoses, oil trap, etc? if so, did you clean out the 2 ports on the block? if it's a turbo, did you clean the PTC? if it's a non- turbo, did you change the flame trap?

its a complete rebuild every thing was done - and checked no less than 3 times before first fire - ive come down to 1 thing - catalytic converter is blocked - checked exhaust and it was really light when my friend pressed the accel.- so my next trick will be to remove the cat and try that - other than that - i might neeed to strip the engine down and start again

Before you do a strip down again you should look into getting a professional leak down done. That will put your mind at ease. Good or bad it will answer the question.