Did compression test. 1 low cylinder!!!

[lillev23]

Ok this weekend, I performed a compression test on my built motor. I came up with (from #1 to #4) 150, 150, 150, 29. Mind you, this is a motor I built myself with only 40 miles on it. I also have fully built head. After seeing the ####ed up #4 cylinder I did a wet compression test to see if it was a ring, and it only went up 6 psi. I doubt it is a head gasket because I'm not mixing oil and water(although the head gasket has been torqued down a couple of times) . It can't be cam timing because #1 would have been off also. The only other thing I can think of is it being one of the four valves in #4 is not seating correctly. The last time I got my head resurfaced, the machinist said all the valves were seating perfectly. Also I have a copper o-ringed block on a mitsu mls. To be honest, the last time I took my head off I didn't ger a new o-ring installed. Could that also be part of my problem? Any help would be greatly appreciated so get this bi*** back on the road.

 

[oldman]

Instead of guessing, perform a leakdown test which will pin point where the leaks are.

 

[lillev23]

I think I'm just going to pull the head off and have the valves checked to see if they are sealing up. Hate to be a dumbass, but how do you perform a leakdown test? Nevermind. I'll just find it in the old forums. I know how you ol' moderators have a B@tch fit about repetitive questions

 

[lillev23]

Well since there isn't a single auto parts store in Albany, Ga that sells a leakdown tester, I decided to find the problem a more primitive, but still effective way. After taking the head off and removing the cams, I took some gasoline and poured it into the intake ports and then the exhaust ports of cyl. #4 to see which ones will leak gas past the seat. I came up with the exhaust valve closest to the trans. having a bad leak. The other three didn't leak any gas except for that one. I'm still not sure why it was leaking, but it shouldn't be a bent valve b/c I have not done anything or pushed the car hard enough for anything like that to happen. Anyways I am going to take it to my local machine shop tomorrow afternoon to find out what it will take to fix it