ok so I have a built motor everything done from the ground up. Car has idled maybe a total of ten minutes. Out of that ten minutes some of the time the number three cylinder wasn't firing bc of bad plug wire. Compression is 180 across the board other than number three it's 150. I havent ran the car but to check and see if the plug wire would fix it not firing which it did. Is it a possibility that the rings in that cylinder haven't seated properly bc of this? I am gonna drive it for about 15 miles and see of it goes up. Only other thing I can think is bent valve. Bc valve lash is good. Any ideas or insight

 

it is possible that it ring washed that cylinder. I would think it should improve when you put some miles on it... why the hell did you let the car idle on 3 for 10 minutes?!

 

I say drive it for a while and see how it does. It sounds like the rings got washed due to too much fuel in the cyl.

 

squirt oil in the cyl and retest , if it goes up its ring if not its valve. the only time i ever saw that much of a difference on a fresh motor is due to broken ring, is there a chance it was cracked during install?

 

ok guys... the reason i ran it for about ten minutes is b/c it was intermittenly running on 3 cylinders! i didnt just sit there and let it run on 3 cylinders! i drove it about 5 miles and now my compresion is 185 170 185 190.... i need to do a valve adjustment again to make sure they are all good... but it seems like the compression went up... i think the motor needs to break in but more insight would be nice.... and when i came home car was running great! went to start it and cylinder 3 isnt working now? again but still compresses 170 its intermittenly working as it wants any ideas?

 

i did the oil in the cylinder and it didnt go up? so i dont know wtf????

 

bent valve, bad valve guide could be it. Had the same problem on a ls turbo and ended up being in the head.

 

new bronze valve guides in head

 

put some miles on it. It hasn't had a chance to seat. I don't think you wore the hone off of the cylinders in 10 min. Drive it hard if your tune allows. oops, didn't see the post you stated that it is still missing in cylinder 3. Find out if it's fuel, ign, or compression related. Then track it down that way. Your best bet is to do some testing first.

 

did u fix the #3 misfire problem? any smoking or oil consumption?

get 100 or 200 miles on it and see if the compression begins to even out. if you are seriously concerned try and do a leakdown test

 

we had a leak down tester and put air in that one cylinder and i think it had 60 percent leak down.... i will have to perform another test on it to make sure.... im buying a wideband in the morning and gonna make it where car is safe to drive once i fix the misfire issue and put some miles on it.....

 

When you did the leak down, where was the air coming from? That should tell you where the issue is. Keep in mind you most likely still need some break in time. As for the new guides. Keep in mind that if the installer does not get them in there perfect, a valve can bend slightly over time. So since your numbers went up, sounds like the rings might just need more seat time. Good luck.

 

Update. I took head off bc compression was still lower than others and I poured fluid in intake ports and one of the valves leaked it was a steady drip. So I'm guessing it's bent which could be my issue. One exhast valve let a lilttle fluid seep past but it was very little. Going to machine shop tomorrow

 

update..... Pulled head and intake valve was not seating correctly. Machine shop fixed it now compression is 180 across the board

 

could just be a ****ed ring

 

No, its not.

 

It could be a bad ground! lol