After going over everything once again, we discovered:

after compression test
cyl. #3 - no compression
cyl. #6 - no compression

after cylinder leak down test
cyl. #3 - exhaust valve leaking
cyl. #6 - intake valve leaking

testing done first time did not have these faults - it showed good compression through all cylinders, so we can supposedly rule out the any valves leaks.

Problems:
Cyl. #3 on TDC - the exhaust valve lifter cannot be turned by hand
Cyl. #6 on TDC - the intake valve lifter cannot be turned by hand

my theory: lifters pressurized or sticking and keeping valves slightly open
Is this at all possible? Could they be working on and off giving me all the trouble?

thanx for all ur responses to my last posts gain!, Jozsef