stuck valve symptoms/fixes

[RobertN]

I am looking at a Farmall Cub that the owner believes has a sticky valve(it is about 5 hours from me; I have seen pictures).

What would be the symptoms of of a sticky valve? I would guess it could stick open or closed, but if it sticks open could hit the piston potentially?

What would be a typical fix for something like this?

 

[Soundguy]

Flathead right? Probably not much chance of the valve kissing the piston?

On our old fords.. we see sticky (open) valves from time to time. Shows up as a low compression # on a dry compression test for a cylinder that does not improve with a wet test.

Might also hear poppong in the exhaust.

On the fords.. easiest way to verify was to pop the valve side covers off and run the engine over and 'look' at them to verify functioning.. course this won't tell you if you have a burned seat.. etc.

Also.. I'm not a fan of 'mechanic in a bottle'.. but this is one of the 'good' times to use MMO ( marvel mystery oil ). Add it to the gas, and oil, and we even hose down the offending valves and manually work them back and forth... the stuff is cheap.. use alot of it.

Keep in mind that it is a solvent, and will thin the oil some. What I like to do is treat the gas and oil, and the valve itself, and then run for say 10 hours.. and then do an oil change. Generally if it is a minor case of 'sticky' valves.. this does the trick. For anything else.. you'll be pulling the head.. etc.

Soundguy