I have a 1990 accord EX with 216,000 miles on an F22A4 and while I am in the midst of tearing it down still something has come up that puzzles me.

This car has had all its regular maintenance done including 3 timing belt changes.

First the failure; zero compression in cylinder #2 (hence my user name) rigged up a blow gun thru the plug hole and with the rockers loose I could feel the air blowing out the tailpipe. All other cylinders were 110 or 115 lbs.

I stripped the head last night and the strangest part of all is that every one of the exhaust valves is bent/warped slightly, they still pull up tight with the spring pressure but with no spring pressure they are definitely not sitting concentric to the seat (except cylinder #2 where the exhaust valves aren’t even close to seating) Intake valves look awesome… weird eh??

Cylinders # 2&3 move in parallel so #3 should be just as bad as #2 if there was any contact at all correct? There is no excessive carbon buildup in #2 valve, piston or otherwise.

Are the exhaust valves prone to warping from heat?

 

The entire exhaust side gets hotter and is more likely to have problems than the intake side. That said, I don't know that your exhaust valves are prone to warping specificly. I also don't know how thoroughly you inspected the valves to conclude that they are warped, so I want to point out that the valves can be off-center if the guides are damaged. Valve guide wear is much more common that warped valves.

 

I noticed the problem when I started lapping the valves, the first one was only getting one little shiny spot on the sealing surface so upon further inspection that "side" would always contact the seat when closed with very little pressure no matter which position I rotated the valve to. The others are the same, stems feel snug in the guides which isn't a technical measurement by any means but they're not excessively loose either.

 

I'd guess someone owned the car before you? At 216k I'm hesitant to say one specific problem occurred to damage the valves but heat was certainly involved. Whether it happened over a long period of pushing the car too hard at too high RPM or if there was a single major instance of overheating, either way you fix em, make sure the cooling and oiling systems are ok and move on.

 

Yes, I'm the second owner.
Thanks for brainstorming with me.
wanted to make sure I wasn't missing something that'll cause it to happen again as soon as I start it up again.

Thanks again.