tip for Fixing a sticky valve?

I got the Jeep running after 14 years but it has a bit of a miss on the passenger side. A buddy showed me a trick where you hold a rag at the exhaust and it will get sucked back in a bit as that cylinder fires. Weird, it worked like a dream and the rag pulled in a bit before being pushed out by the next cylinder. So is a valve stuck partiality open? If its stuck how can I get it unstuck? If I must pull the heads I can but would rather just have it work itself out. Will I damage the engine running it this way. It's the dauntless 225 v6 any help would be awesome.

 

A burnt exhaust valve will have the same tailpipe results you describe.
A simple compression test can help; then compressed air introduced into the cylinder when the piston is at TDC will reveal the bad valve on that weak cylinder.

 

What you describe is an open exhaust valve. It's sucking as the intake valve is closed and the piston is going down in the cylinder, normally the power stroke. There's no power because there is no compression. Basically three possibilities, burned valve most likely, broken valve spring, or bent valve stem. A compression check will tell you which one it is. If you have headers you can use a surface temp gauge to tell which one by measuring the temps of each tube, much quicker and easier than a compression check.

 

Probably. If the valve is stuck, the spring won't keep pressure on the valve train and the push-rod may pop out of the rocker seat. If the valve is bent or burned, the exhaust gas will eventually torch a groove that will require a new valve seat. Then again it may just break off and chew up everything in that cylinder.

 

I had that problem (rusted/stuck) valves in two engines 225v6's and I removed the rocker assy and sprayed with penetrating oil and tapped the top with a rubber hammer. Took about two to three minutes to get the valves to move thru complete up/down travel. You can also check the push-rods for straightness at this time.

 

I found this on a search. Suspected a stuck valve. Removed the valve cover and sprayed the valve with PB blaster. Reapplied over a period of about one hour. Cleaned the plug, replaced the valve cover and started it up. It released immediately. I suspect it had not been driven down the road in about five years or so. It runs better than I expected. Thanks for the tip.