stuck valve

bull_islander

Looking for help dealing with a stuck valve. 52 C8, #8 valve (closest to the firewall) is stuck (no compression from that cylinder). I've had the car a little over a year and it happened once before and fixed itself after a few miles. No such luck the second time.
I've put Marvel mystery oil in the crankcase and also pulled the spark plug and put a little in there and let soak for a week, but no easy remedy yet. Any other tricks out there?
Thanks.

Ol racer

FYI

You need to continue Marvel oil in the sparkplug hole with the piston up so oil runs into relief, valve and guide. (Its difficult to get the oil under the valve). Try (if possible)to bend a narrow rod to push valve down then crank over and repeat until frees.



Once the valve is free I would use a upper cyl lube in the fuel (not crankcase) until you find the root cause. (Weak valve spring, corrosion, etc).I am certain you will get other good suggestions. Good Luck

hudsn47

Here's the thread where I got help for my stuck valve. This worked well for me.



http://www.classiccar.com/forums/showthread.php?t=6984&highlight=stuck+valve

Clutchguy

Something to think about??.Most of the time that your engine sticks the valves is because of poor or very bad gas[stale]!! Modern fuel does not last very long,and necessary precautions should be utilized when letting the vehicle set or not run.I have found that "Seafoam"brand fuel stabilizer works very well.The varnish residue that is left in the fuel tank,you know,that very bad smelling stuff,is also built up around all the valve stems.The engine might seem to run ok,at first,then this stuff builds up around the valve stems,and if the engine is all warmed up running on this bad gas it might not be as noticeable until you shut off the engine and it is allowed to cool completely,this build up of varnish is like cement.It will stick the valve and the valve guide as one!! You can try to use Gumout carb cleaner but you have to be careful using this because it will wash the cylinder/cylinders down and cause the rings to stick too.I guess the point I am trying to explain is make sure that the fuel is fresh and not contaminated or stale.If you don't or didn't remove the gas tank,clean it out/restore,and then put fresh fuel in it,it WILL eat all the nasty old varnish out,circulate that around,mix,then burn and most of the time cause the valves to stick!! I have seen this many,many times.If this engine has been rebuilt,it doesn't take much to stick the valve in the new guides.:eek:

Park_W

I'd want to confirm that it's really a stuck valve, by removing the valve cover and observing while cranking it over. Or have you already confirmed that by putting that cyl on TDC and blowing compressed air into the spark plug hole, listening to see whether it's coming out the tailpipe or through the carb. In any case, if it is a stuck valve, by watching with the tappet cover removed you'll know which one and can squirt some gumout right up into the valve guide around the stem. That could help break it loose.

Geoff

In my experience sticking valves after the engine has been sitting for a long while are primarily caused by rust. This is usually caused by The worst thing that people do after coming home is leaving the car out, perhaps unload, give it a dust down and polish, and then later on drive it in to the garage, and switch off. Don't ever do this, as the moisture generated in a cold start will be left on the exhaust valve stems, and you are headed for trouble. Sure, varnish will also cause the problem, but if so, this will be manifested when the engine is hot. The same thing used to happen with the very high lead content in fuels back in the 60's and 70's, when the lead residue would build up on the valve stems, causing them to bind in the guide. The best way to clear gum off the stem is to get some lacquer thinners down on the stem, but this isn't the easiest, as you have to get some sort of nozzle down past the exhaust valve. To free the valve in your Hudeson 8 motor, you can try a punch on top of the valve, down through the spark plug hole. Flood it with Marvel oil first, and then punch the valve down, and see how you get on. You may have to do it a few times, but it should come right. Good luck,

Geoff.

Clutchguy

Bull islander,do you know the status of the fuel tank or the engine?

bull_islander

"do you know the status of the fuel tank or the engine?"

Completely, without a doubt? No. I know the gentleman I bought it from put the engine back together and that the gas tank had been off. But, how old was the gasoline in the tank? Not really sure. I could see it easily being a year old.

I'll try to find the top of the valve and tap it from the plug hole and I'll keep putting some marvel in there. Will also get some fuel stabilizer and add that as well to the gas tank.

[Deleted User]

Be careful when working with that stuck valve. Several years ago {about 30 ] I was trying to free a stuck valve on an old ford. It was running and I lightly tapped it with a copper hammer. It freed up. I steped aside and just then the valve let go . The valve stem stuck in the beam overhead. Theres up to 200 lbs. of pressure on stock compressed springs, so be aware.

bull_islander

I tried again today. I tapped on the exhaust valve (the one that is directly under the spark plug hole) and turned the engine over while looking in and could see it moving up and down.
Checked the compression again and it is still zero.
Does that mean it's the intake valve that's sticking? That one does not seem accessible at all through the plug hole.
Do I need to pull the head or the valve cover? what's the best approach from here?
BTW, poured some more marvel in there...

Geoff

You probably need to get under and take the valve chamber cover off and see if there is actually a valve stuck. It would be very unusual to have an inlet valve stuck. However, if it is, you would be able to get a vice-grip on the bottom of the stem and give a wiggle aroudn which should loosen it. good luck,

Geoff.

Unknown

I would recommend putting some compressed air down that spark plug hole and see where the air comes out. If it comes out the crankcase you have a hole in the piston. If it comes out the intake manifold its the intake valve. If it comes out the exhaust its the exhaust valve. Turn the engine over at intervals and choose the most common denominator.

bull_islander

To follow up...

I had taken the valve covers off and pulled the valve down with vice grips as Geoff recommended. After pulling it down, the engine pushed it back up and it stayed up. I was able to pull it down again one more time and it again went back up not to come back down.
Then I've pulled the head off. Yes, the intake valve on #8 is/was sticking in the up position. Very had to put back down tapping with a hammer.
Time goes on with no time to look at it. I found a purchased a can of Aero Kroil as recommended by Paul Schuster. 10 minutes after spraying it on the valve it had gone down on it's own. And it now goes up and down like it should. (http://www.kanolabs.com/). I think I'm going to buy a case of that stuff and use it for stocking stuffers.
My question is: Should I go ahead a replace the valves while I have the covers and the head off? Should I do anything else?

Unknown

With the head and valve covers off I would remove the sticking valve. Clean it good and lap it in. To be sure it is seating. Easy to bend the stem when trying to free up.

[Deleted User]

Is it possible you have a hole in the piston? Detonation from poor gas can cause a hot spot on the piston than can everntually burn a hole.



Harry