Changing valve seals
Thread Starter
Teching In
Joined: Feb 2004
Posts: 11
Likes: 0
From: Springfield, MO
Changing valve seals While changing valve seals on cylinder #7 I used 60psi of air thru the spark plug hole to hold the valves in place. In about 15-20 minutes the air compressor lost 30 psi of pressure. Is this normal? Would this much air go past the piston rings possibly?
Yes....leave the compressor on so it can keep up. And, for god's sake, work faster! 15-20 min. on 1 cylinder 
J/K
Seriously, though, as long as you don't hear hissing from the intake then air isn't going past the valves. So you should be ok. You'd have to do a leak down test to determine if you're having ring seal issues. But the rings aren't air tight so you'll get a bunch of air escaping past them especially after 15-20 minutes.
BTW, I'm just west of Springfield.
J/KSeriously, though, as long as you don't hear hissing from the intake then air isn't going past the valves. So you should be ok. You'd have to do a leak down test to determine if you're having ring seal issues. But the rings aren't air tight so you'll get a bunch of air escaping past them especially after 15-20 minutes.
BTW, I'm just west of Springfield.
Thread Starter
Teching In
Joined: Feb 2004
Posts: 11
Likes: 0
From: Springfield, MO
Thanks for the reply 1fast.
It took nearly 15-20 minutes just to place the locks back in place. #7 cylinder is a bitch to work on
.
I wasn't sure how much air would find its way past the rings. Just wanted to find out what someone else thought.
It took nearly 15-20 minutes just to place the locks back in place. #7 cylinder is a bitch to work on
. I wasn't sure how much air would find its way past the rings. Just wanted to find out what someone else thought.
30 psi over 15 minutes is ok. Mine were like that and my car uses about 1 qt./oil change and only has a little piston noise on cold start up, then it goes away.
For reference, look how fast the air bleeds off when you are turning the engine over by hand when trying to bring it to TDC (sparkplug in ofcourse, lol).
For reference, look how fast the air bleeds off when you are turning the engine over by hand when trying to bring it to TDC (sparkplug in ofcourse, lol).
