Farmall A valves stuck open

[darkeagle10x]

New here but have lurked and searched a lot. After reading everything I can search out about stuck valves. I'm now at a loss. The old girl ran fine when I parked it but it's sat for over a year under cover. Wanted to show my 10 year old grandson about cranking to start.

Well, it didn't feel quite right and no spark. Checked many things and thought it might be time to go over everything and teach the grandson. We changed plugs, coil, condenser, rebuilt the carb, dropped oil pan and cleaned it, etc. Then realized we also had no compression. Turns out one valve on each cylinder is open. After reading how to "unstick" them, I sprayed and tapped on them and got them to move down BUT the spring won't bring them back up. So now they are down as low as they go and I cant get them to return. I have sprayed and tapped (hoping to "pop" them loose) daily for over two weeks. Kroil and Gibbs but no movement back up. Tried as best I can to pry and tap with a screwdriver levered under the spring but to no avail. Also tried as best I can to reach into the cylinder and pry up but no movement.

Now that the springs are fully compressed, I can't get a spring compressor to give me clearance to remove the keepers and springs. I'm tempted to cut the keeper with a small dremel so I can get vice grips on the valve stem and try working them until they free up. I read one post about pushing clothes line into the cylinder and hand turning - tried it with no success. It just comes to a dead stop and I don't want to force things.

This was also converted to 12V starting but always started great with the crank - until it didn't.

I'm puzzled since the valves moved down (albeit not easily) but won't come up even with help. It's been two weeks of spraying them daily.

I really don't want to pull the head. That is over my pay grade these days.

Looking for advice.

[Jim Becker]

Are the stuck valves all intake, all exhaust, or some of each? The valve stems no doubt have some wear. After you tapped them down as far as they can possibly go, they are more open than the normal travel. So some unworn portions of the valve stems are now down inside the valve guides. Whatever gunk has them sticking is now in a place with a tighter fit than what you started with. So no surprise that they are resisting coming back up.

You may be able to get them to come up if you can rotate them a little bit. You might be able to get them to turn by grabbing the washer on top of the spring with a pair of pliers and wiggling it in rotation. Go very carefully and only try to move it a little bit. If you get too ham fisted you will rotate the washer on the valve, which you don't want to happen. If a little of that doesn't work, try reaching straight down on the top of the washer with your pliers and pulling up as you wiggle it in rotation.

A pair of Channel Locks may work well for the first try, Vice Grips for the second. Be gentle with the Vice Grips. If you clamp tight enough to leave a mark on the washer, you went too tight.

[darkeagle10x]

Thanks Jim. It is a mix on the valves. I'll give it another try with your idea this afternoon. Your explanation of how they seem to be stuck now makes good sense. If I can just get them back up a bit the spring should take over. If I can't move them, am I crazy to try cutting the keeper to remove the spring and get a better grip to rotate? I have another A that I can salvage parts from to replace what I cut.

[Rick Spivey]

I don't think it would be possible to cut the keepers away without damaging the valve stems as well. If Jim's tips don't work, I would pull the head, and probably have it reworked by a machine shop while it was out. But at least you would be able to access the other end of the valve, and gently persuade it to close again.

[Jim Becker]

I second what Rick said. You are running out of reasonable options without removing the head. Even if you were able to get the keepers off without damaging the valve stems, reinstalling springs and keepers without access to the other end of the valves is difficult.

[tst]

I have had a few like this, one trick that has worked for me is heat, it does take patience, use a heat gun with a narrow nozzle on the end of it and heat around the valve guide, spray you penatrating oil once and a while the heat will maybe expand the guide to let go of the valve and let the oil run down the stem

[Gary Dotson]

Trying to cut the keepers off would just dig the hole deeper. I would maybe, make a tool to fit under the valve spring retainer and connect to a slide hammer. Use that to force them closed. If that doesn’t work, I’d pull the head.

[Eugene]

I would maybe, make a tool to fit under the valve spring retainer and connect to a slide hammer. Use that to force them closed. If that doesn’t work, I’d pull the head.

You didn't say how hard you hit the valve stem. Anything more than a gentle tap, -- pull the head.

You may be able to get two of the very thin crowbars used for siding or trim or very thin flat bladed screw drivers under the valve spring. Two more thin screw drivers used to wedge up the earlier screw drivers up.

[Jim Becker]

You may be able to get two of the very thin crowbars used for siding or trim or very thin flat bladed screw drivers under the valve spring. Two more thin screw drivers used to wedge up the earlier screw drivers up.

Possibly two putty knives, I'd try going into the spring rather than completely at the end. Do it very close to the head end of the spring, not the end attached to the valve.

[darkeagle10x]

Thanks for all the ideas. I'm sure I have hit them too hard by the info you've given. When I saw them move a bit I figured I had it licked so kept on until they didn't move expecting them to spring back. I'll machine a small wedge shaped piece and see if I can force them back up but I think I may be destined to pull the head. If that is the case, am I looking at simply pulling it and getting them to move again and put back on with a new gasket or if I go that far, I should be doing more?

[tst]

if its apart remove the stuck valves, clean out the carbon and crud causing them to stick

[darkeagle10x]

Well, I guess I've really done a job on them. Even with a wedge shape fork, they don't move. I'll give it one more try and if they don't move, I'll pull the head. Just haven't done that since 9th grade shop class and I'm 63 now so it's been a few years.

[darkeagle10x]

Pulled the head and was able to move them a little. I've taken it to a friend who can clean it up better than I can (retired auto and small engine mechanic). Things looked pretty good so far. I have a new gasket ready when he gets the head cleaned. Should I use some type of gasket sealant like permatex or nothing?

[Gary Dotson]

The head gasket sealant depends on the gasket. If the gasket is metal faced, on both sides, spray it with Permatex Copper Spray A Gasket. If it’s metal on one side only, spray only the metal side. (Fel-Pro). If both sides of the gasket are composition material, use no sealant. (I doubt you’ll have that style). Spend considerable time cleaning the block surface, needs to be squeaky clean. Don’t turn the engine, for any reason, while the head is off, you risk raising the sleeves. If you really must turn it, you can use flat washers and a couple short pieces of conduit or pipe on two of the head studs to assure you they don’t move.

[darkeagle10x]

Good information Gary. I would not have thought about the sleeves. I believe my gasket is Fel-pro and it is metal both sides. I got the head back from my friend and it looks great. He also "touched up" the valve seats a little. Now I need to get the other surface clean and pick up some gasket sealer.