Valves stuck

[Two Crabs]

I have been working on a 1941 that has two cylinders with no compression. I have soaked both with a mixture of Actone and ATF. still no joy in freeing up the valves.
Any ideas how to push them back down.?
Can you stick a rod or screwdriver into the spark plug hole and tap them down?

[Doug Houston]

I had the same problem a few years back. My pet mechanic came to the rescue. With all plugs out, he gorged the combustion chamber with carburetor cleaner, and had a little video probe ready. the use of Acetone (the correct spelling) would never do the job.

Now, I assume that the problem is varnish on the "hot" side of the valve (the side in the combustion chamber, and not the side in the valve gallery). Let the carb cleaner set in the chamber for possibly 1/2 hour. If you have the little video probe made bu Snap-On, you'll be able to see the valve move after you tap it gently with a steel rod.

Don't get over-anxious with it. It will take time for the carb cleaner to soften the varnish.

Now, through all of the above, I have assumed that you have STUCK valves, and not BURNED ones!

[Two Crabs]

I'll try the carb. cleaner next and tapping the exhaust valve down.
Acetone ( My big fingers missed the "e last time ) and ATF worked on two other cylinders that were stuck.

I just can't get these last two to free up.

[harvey b]

another thing is to make sure the valves will move,the cam has to be not in position to open the valve?,.Not sure how to do this without taking the valley cover off?.Old stale gas is usually the cause of the varnish build up,if you get it to run,drain off the old gas or maybe try some fuel stabilizer,i like Marvel Mystery Oil for a stabilizer,have used it for the last 8 years and my stuff always runs better in the spring then it did in the fall.Good Luck

[Steve Passmore]

If you attempt to tap these values through the plug hole you will bend them because your tool is on an angle. The easiest thing to do here and would save a heap of time from the beginning is to remove the cylinder head, thats if it will remove of coarse and  yes, I'm well aware the bolts protrude into the water jacket, so what I would do is try each bolt in turn just a little to see if each will move before undoing them, if they all move the head can be off in 15 minutes, then the values are perfectly visible and easier for tapping parallel.

[Jeff Rosansky CLC #28373]

When it is up and running, add some Marvels to the oil as the previous post suggests.  Sometimes airplane engines have 'morning sickness' at the first start of the day.  Caused by sticking exhaust valves because of the varnish and soot buildup.  We just run Marvels in the oil and it usually clears up.
Jeff