valve leak?
 

I supply 90 psi. air pressure on the combustion chamber side throught the well sealed plate , and I fill the intake and exhaust port with alcool,and no one seal perfectly.?
Iny input,Thank?

Re: valve leak?
 

Did you check them with the valve spring at your closed seat pressure? If you did then id look at the valve job . Jim Hanig

Re: valve leak?
 

It depends on how much it's bubbling, It is almost impossible to get valves sealed to point where they won't bubble,whether water,soap& water etc.
If valves/seats have'nt been lapped in you may do that and see improvement,tap on valves so it bounces them off seats sometimes helps also.
I leak valves on engines by hooking air straight in plug hole I have 160 psi air in my shop
I have rockers removed,I cover ports with hand to feel for leakage if is leaking you will feel pressure build against your hand,lots of times you can tap on tip of valve and will seal.
You can have valve job with 100% seal on vacc.tester and still bubble soap.
The most accurate thing you could do is use leakdown tester with heads on engine.

If you have more air press available see if that makes worse or better.
Mike Taylor 3601