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Due to infrequent use our 1950 eight (288) has a stuck valve in cylinder #1. We tried daily driving for the past month with Sea Foam in oil and gas with no success un-sticking the valve. Is it possible to solve the issue with just the head removed or it there more to it? I have found no procedure in any of the service manuals I have except to state sticky valves can be a problem. I would certainly appreciate any advise/direction to get me started. I have all the gaskets sets, I think, necessary to get down to remove and replace the valve cover.

old shade tree mechanic trick my dad taught me for a sticky valve on a flathead was to take the head off, have someone crank the engine, and watch for the valve to open and stick. bop it with a mallet, repeat. if it starts to operate normally you're done. if not, the valve access panel on the side of the block comes off next and you can replace the valve

50Cal, i'm in the East Bay. The '40 120 I had long ago would often have a stuck valve after sitting a couple months between runs, esp. after the moist air during rainy season.
What worked was pulling the spark plugs, and trying to angle the squirt gun to get Marvel Mystery Oil over the valves. Then relaxed, fussed with car a few minutes, stuffed rags in the spark plug holes so as not to make a mess while cranking the engine a few times to work the Marvel and get most of it out of the cylinders.

Then put the plugs back in--remember, only wrist tight w/ our 10mm plugs and copper spark plug gaskets better-- started the car. Smoked for a few minutes, but far enough from the neighbors not to attract attention. 1940 Packards introduced austenitic valves to alleviate the problem.

As mentioned, a late aero/auto mechanic/machinist pilot friend who as a very young Pan Am wrench at the Alameda Naval Air Station during War II, said Pan Am's chief of maintenance swore by Marvel, ordered it by the 55-gallon drum.

Any trouble with those big Wright Cyclones meant a long, wet walk home.

Marvel Oil is an excellent product, as is Sea Foam.

You may have a problem with rust, as opposed to carbon or gum.

Before I removed the cylinder head, I'd remove the inner fender panel and the valve chamber covers and look the situation over. Applying oil and solvent to the valve stem from the cylinder end and from the lifter end may help loosen it.

It may also be possible move the engine so as to put the lifter under the stuck valve at its lowest position, then remove the valve lock and valve spring.

With the spring out of the way, it may be possible to use a small set of vise grip pliers to clamp onto the valve stem and try to twist it, or tap downward on the vise grip jaws. Use of brass shim stock will protect the valve stem from the plier jaws. With some engines, valve heads can be accessed via the spark plug hole, and gentle pressure applied with some suitable tool. The 10 MM plugs on the Packard would limit access, but the plug being located over the exhaust valve may allow some access. I'd use smothiing like a 3/16 brass rod o or soft steel to ttap on the valve head.
Any forceful tapping may bend the valve.

Taping the portion of the tool that may contact the spark plug threads will prevent damage to them.

If you can get the valve to move down even a tiny bit, it may become possible to gently twist it. Twisting and pushing it back up and then down while applying more oil will usually allow more and more up and down movement until the valve is fully free. Care and patience can get results.


Using Marvel Oil in the gas tank according to directions may help prevent future valve problems when the car is in storage.

Even if you have to pull the head, you'll still have to avoid applying any heavy force to the valve. You don't want to loosen the valve guide in the block, or bend anything. Be sure the cam and lifter are at the lowest position.

Thanks for the replies to my stuck valve problem. Great suggestions and now have my weekend planned. Will work down the list after first getting some Marvel.

What have you done to diagnose it as a stuck valve? Or just assuming?
Noise can be a few things. Zero compression can also.
The side adjustment cover comes off and you can look at the valves/tappets.
Without knowing any info on the vehicle, it's near impossible to diagnose or offer solutions over the internet.
Some of these products can also cause issues with deposits. These engines don't have full filtration so the block may be crudded up and cause a lack of lubrication issue. Adding stuff to oil or gas can dislodge deposits and make things worse.
Do you crank without firing until the oil pressure comes up before starting to get oil to the cylinders or do you start it and rev to warm up? Former not the later is good practice.

How we determined it was a stuck valve. Upon starting up from storage it was missing a beat and never fired on all eight cylinders. Compression test was zero on #1. Also took it to a trusted local mechanic, who has helped me in the past, to check it out and agreed to the stuck valve diagnosis.
We ruled out sludge or deposits as the engine only has about 2,500 miles on a rebuild and 90% of the gas/oil has had Seaform or equivalent additives.
Your suggestion to crank without firing is good except our ignition switch only has an "ON" position and does not crank without firing. According to some literature my '50 should have come with a second position, so it may have been changed out at some point.

Remove the passenger front wheel, then remove the access panel inside the wheel well. There are two covers for the valves, one on either side of the exhaust manifold and downpipe. Remove these (including the road draft tube) and you will have easy visual access to all the valves. You may be able to see sticking valves right away, depending on the position of the camshaft.

To crank without firing, disconnect the ignition wire to the coil. You may also want to remove all the spark plugs in order for the engine to turn easier.

Crank the engine and watch the action of the valves. If one is stuck it will be very apparent.

If you have a stuck valve it could be corrosion, gum/varnish, or a bent valve. Gum/varnish and corrosion can be helped with Marvel and Seafoam. With the valves open to access you can spray or squirt Marvel or Seafoam directly on the stems. Injecting some Marvel into the spark plug holes will allow it to pool around the valve stems from the top and do some work.

Turning the engine by hand at the crankshaft pulley nut will help to cycle the engine and gently push on the valves. Several days of applying the above and turning the engine may help.

Heat cycles also help. Warming the car up will sometimes free sticky valves. All of the above has worked for me on two separate cars.

If it is a bent valve the only thing to do is remove the head and remove the valve. Or if the above doesn't work then you will also need to remove the head. No harm in trying to free them up with some magic liquids.

-Kevin