Stuck Valve ?

[46HARLEY]

Hi all, I have a question about a stuck valve. 1946 V8, appears No 4 exhaust valve is stuck. Tried soaking and running the engine no change. My question is it better to take head off or remove the intake ? Open to any other options.
Thanks Larry

[Jack E/NJ]

>>Tried soaking and running the engine no change.>>


Probably haven't soaked or ran it long enough. If it was mine, I'd liberally squirt an MMO stream at it through the plug hole, Maybe let it marinate of a few days. Mix some MMO in the gas tank. Add a pint of MMO to the oil.Then drive it for a few hundred miles. Check it again. Repeat if needed.

[flatjack9]

Turn the engine to get the lifter on the base circle. Tap the valve down carefully. Turn the engine over and repeat.

[tubman]

I would look the valve assembly (especially the spring) over carefully first to make sure there are no external problems if you have not already done so.

[alanwoodieman]

I had a stuck valve in an 8ba and finally pulled head/intake off and it had been stuck for a long time just off the seat, could not get the valve out of the guide even after pulling valve out. this was done after soaking it for 3 months-- my though is it stuck or occasionally sticking?

[pistonbroke]

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Pull the head , bring the piston up on its compression stroke and tap the valve down. Then roll the crank two full revolutions and repeat as many times as necessary using an oil of your choice with each opening to get it moving as it should. Reassemble and enjoy. Tim

[flatjack9]

No need to take the head off.

[cas3]

I agree with flatjack. I go in the spark plug hole with an allen wrench. Try to hit the center of the valve.

[46HARLEY]

Originally Posted by cas3

I agree with flatjack. I go in the spark plug hole with an allen wrench. Try to hit the center of the valve.

Thanks for all the responses. Could you tell me some more about this Allen wrench process. I have it soaking in acetone and Marvel, would love to get it to move without taking it apart. If I have to I will start with just the intake. Thanks Larry

[Karl Wolf]

Originally Posted by 46HARLEY

Thanks for all the responses. Could you tell me some more about this Allen wrench process. I have it soaking in acetone and Marvel, would love to get it to move without taking it apart. If I have to I will start with just the intake. Thanks Larry

The idea with the hex key is that the side of the head of the valve can be seen thru the spark plug hole. It is best to hit the top of the valve in its center to not bend the valve.
This can be done by inserting a hex key (bigger the better) so as to have the short end over the valve, with slight tilt.

Karl

[tubman]

It sounds like you've been at this for a while now. I think you're gonna hafta take it apart. I'd remove the intake first and take a gander. Who knows? You may have have a broken spring or maybe a keeper slipped out. In such a case, no amount of soaking and tapping will help. If everything looks good, then maybe try the "Allen Wench Process" . Personally, I'd remove the head so I could "tap" without taking a chance on bending the valve.

[dean333]

Is it stuck open or closed?

[RalphG]

I had several stuck valves on both the 39 Deluxe and the 52 Merc. Stuck open so I could spray real penetrating oil into the spark plug hole onto the valve and allow that to soak down the stem. Eventually tried some careful tapping with a small punch and hammer. They all freed up and worked just fine after that.

[drolston]

In the first few hundred miles after completely rebuilding my 59a/b, it took several sessions of drizzling MMO down the intake to get it running smooth. Now, with about 3,000 miles on it, every time I let my 59a/b sit for a month or so, it still runs rough for a while after starting with a very erratic vacuum gauge. Then after about five minutes, everything smooths out. I put 4 oz of MMO in the tank at every refill.


If you are able to get it unstuck with the above tricks, it may be a short lived fix. You might consider doing the drizzle thing a few times, and running MMO in the gas and crankcase.

[flatjack9]

No need for an allen wrench. The exhaust valve is directly under the spark plug opening. Easy to hit the center

[46HARLEY]

Update- Assumed stuck exhaust valve, no compression. Pulled the intake, valves working no problem. Pulled the head expecting the worst, found everything looking just fine. Gasket look good, cylinder looked great. Kinda left dumbfounded, checked compression again just before tear down. Put piston down and filled with marvel mystery. Stuck ring ? Would pull my hair out, but not a lot left. Curious about what I’ll do next. Larry

[Seth Swoboda]

Did you do a compression check? What was the compression on the suspect cylinder? Just curious and not trying to be a smart ass, what where the symptoms? What made you think you had a stuck valve?

[46HARLEY]

Originally Posted by Seth Swoboda

Did you do a compression check? What was the compression on the suspect cylinder? Just curious and not trying to be a smart ass, what where the symptoms? What made you think you had a stuck valve?

Several compression tests after trying to soak suspected valve, could see intake valve move, added oil to cylinder did not help compression. So concluded it was exhaust valve, wrong but that was it or hole in piston ?

[flatjack9]

Could you see the exhaust valve move?

[Jack E/NJ]

> > no compression. Pulled the intake, valves working no problem. > >Put piston down and filled with marvel mystery. Stuck ring ?>>


Do you mean like "zero" psi despite both valves going fully up & down?


And you filled the whole cylinder at BDC with MMO? That's a lotta MMO! Risks a hydrolock!