Intermittent sticking valve

[GOSFAST]

Originally Posted by Mark's 37

My 37 221 V8 has what I think is an intermittent sticking valve. It drops a cylinder about every 4 or 5 seconds at idle. The vacuum gauge is otherwise steady but drops on the same frequency. Compression is good and uniform across all cylinders. This is a rebuilt engine with one piece guides, new valves, springs and adjustable lifters. Engine has about 4000 miles on it. Removed the intake and had a look, adjusted the valves which were not too far off. Nothing visually out of place. I think either a sticky valve/guide or a lifter hanging up intermittently. I am trying to determine which valve is the problem child. Any suggestions on how to find the offending valve?

Hi Mark, can't help locating the "offender", but I can give you this: when we come across anyone in the beginning or the middle of a fresh build we tell them to install bronze-lined guides. I can all but guarantee you'll NEVER experience any "hung" valves anymore!

Thanks, Gary in N.Y.

P.S. Whether or not this is your issue the lined guides are really a must-have in the build regardless! We're literally still doing hundreds every year and have been for a very long time now, stainless valves and the bronze guides, never look back!