hey guys got some questions buddy of mine cyl. #3 has 30psi of compression rest from 180 to 190. put some air in the cyl. and started coming out the exhaust valves automatically i think they are bad pulled the head off valve seats were bad, a piece of valve stuck in the seat the valve was chipped so we put new valves in cyl. #3. used compound, lapped them and then put solution in the exhaust port nothing came out, thought it was a success. Well we put the head back on and its still the same 30psi. going to do a leak-down test just found out my buddy has one. but we put oil in the cylinder and the compression went up so i was wondering is this 100% guarantee the rings or something in the bottom end is bad or can the oil also seal something up in the head maybe such as intake valves, only thing left?

motor-b16, valves that were fixed-exhaust.


thanks

 

After doing the repair & performing a leak down test...where is the air coming from now on cyl. 3? If the psi went up on your wet compression test compared to the psi on the dry compression test. It means that the rings are bad.

 

Yes, the rings are bad.

 

well its also possible that a piece of that chipped valve managed to score up the cylinder wall allowing the air to pass through the rings into the crankcase. when you had the head off how did the cyl walls look? still see a crosshatch? any vertical scoring especially on the intake or exhaust side?

 

Wont adding oil to the cylinder increase compression anyways? I mean your adding a few cc's to the combustion chamber right? And since oil doesnt compress...

 

Im a little confused... Did you do a leakdown test after the initial compression test AND after the repairs? It says you put air in the cylinders, then later found out a buddy has one...Just wondering. Also are you 100% the cylinder was at TDC when doing the leakdown test?

 

Yeap rings are bad. Oil seals the rings when u put it in the cylinder so if it goes up when adding oil rings are 100%bad or cracked sleeve