Stuck valves

B

Billybob57

Member
1931 model A sat for 20 years. Motor was stuck. Added ATV and MMO through plugs and then could rotate the motor back and forth 200 degrees but stops at the same point. Took head off and valve cover. Appears that some valves are frozen to the head as some never push open. No. 4 cylinder valves never open. Questions: Tricks to get valves freed up? The head studs are in good shape. Should they be replaced anyway? I'm worried about breaking one.
 
If you try forcing the stuck valves open, the fiber timing gear teeth will probably be stripped. Try shooting some penetrating oil into the intake and exhaust ports where it hopefully will work it's way through the valve guides. Then try working a knife blade between the lifter and valve stem. You will have .015 inches of clearance. It's easy to tap valves in the open position closed, but not so easy to make them open. Good luck.
 
Yep, get the penetrating oil on the valve stems from the top and bottom and keep spraying it as often as you can.
 
I trust you have removed the head? We have had cases of 'welded valves'.and no snake oil will correct that. We would with a air cut off wheel cut valve spring and valve stem. And with a small machinist jack between the lifter and whats left of the valve stem whats left slowly will come out. Whats a jack? no more than a bolt nut and washer. How get a bolt measure the lifter to the stem put nut on bolt put washers on nut now back off nut valve is moving more washers back off the nut until you can get pry bar under valve on top. Yes you need now new valve and spring and head gasket good to go. This is not a Ford thing its all engines, one stuck valve will lock any engine up. sam
 
The valve guides sit in the bottom of the pockets under the valves, and they need to get penetrating oil. Take the intake & exhaust manifolds off of the engine. Through the ports squirt liberal amounts of oil at the tops of the guides.

Another option is to tap the stuck valve stems sideways. There is some clearance between the stems and guides, so light tapping may help the penetrating oil work into the guides.
As for the studs, leave them alone unless they are visually necked down from corrosion. Good luck.
 
I recently had a stuck valve problem and removed the head and valve cover to expose the problem . Some Model A friends and I lapped the valves, thoroughly cleaned everything and reinstalled. Started the engine and still a stuck valve. Took things apart again and upon close inspection saw that one of the valve keepers was battered and acted like a stop-clip on a storm door plunger ( the moveable clip that slides on a bar that allows one to set the door in any open/close position)' locking the valve in an open position.. Replaced the battered clip with a good one from an old engine and the engine ran fine. Moral of the story: Don't overlook the simple things; all that work for a $1.80 part!
 
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