Larry. You might be lucky and clean up that valve. If you have a boroscope then you can even look at the valve from inside the cylinder. And using the rope trick you can even seal a slight seat problem.
But you are better off pulling that cylinder when dealing with an already stuck valve. A valve is getting stuck for a reason. The exhaust valve overheats and binds in the valve guide. When it loosens up again, the stem is probably scored and the surface of the valve seat might not seal that good anymore. in that case it is better to replce the valve and maybe ream the guide and check for cracks and so on. You need to remove the reason for the stuck valve. Other places to read : http://www.sacskyranch.com/eng176.htm http://www.bowersflybaby.com/tech/fenton.htm#cyl_change_stuck_valve Hartmut ----- Original Message ----- From: Larry Snyder To: Ercoupe Tech List Sent: Saturday, August 09, 2008 2:37 AM Subject: [ercoupe-tech] Sticking Valve Dear tech heads, When we flew up to Wausau, we flew with the engine at about 205 degrees most of the way, but it crept up to 215 briefly on a climb. When we started the plane up to leave on Sunday, we were running on only 3 cylinders. After about a minute, though, it cleared up and ran fine all the way home (it's about 5 1/2 hours each way). I went out a few nights ago to get night current, and it did the same thing. I went out today and pulled it through and the last turn showed no compression. I warmed it up (it ran roughly) and suddenly all was well again. I stopped the engine and pulled it through and voila - compression on all 4 cylinders. I talked to the local mechanic, and he said that I should put Avblend in the oil and fly for an hour or so to clean up the valve stems and guides, so I did. I'll go out tomorrow when it's cold and pull it through again, seeing if the valve is stuck again. If it is, I presume the guide needs to be reamed? Is this where the rope is used to keep the valve in place? How does that work? Or is it better to just pull the jug? I understand that the valve stem is sticking in the guide, I guess I'm not sure I understand the logistics of reaming the guide without removing the cylinder. Also, when I landed this afternoon, it was hot, and I would get a backfire when I when from full throttle to idle. What could cause that? Thanks! Larry Snyder N99340
