Flip the heads over and set them on a bench, make them level. With spark plugs in, pour a liquid in the chamber to the very top. I use parts washer solvent. If the liquid runs out past the valve, you have problems.
When you said "steam/smoke coming out of catch can" , were you refeering to the crankcase catch can? If so, I would lean toward a ring issue. We call that blow-by!!
Yes, the rings can be damaged and it can be very hard to tell from the top.
Last edited by bigblocknotch; 04-21-2011 at 09:51 PM.