No compression on all 4 cylinders

50Trucking

50Trucking

Member
Bought a 31 Coupe that had been setting 20+ years under a shed.
It was a little stuck, added mystery oil to cylinders several times and got it freed up. Turns good with starter.
Rebuilt carb and distributor and fixed other things.
Tried to start it yesterday but would not crank.

Have good spark. Removed a sparkplug and poured in a little gas and it fired on that cylinder back through the muffler.

Thought it might be the timing gear but the distributor turns.

Checked compression on all 4 cylinders and all cylinders had zero compression

What do you guys out there in the Ford community think it could be?

I have not removed the valve cover to see if a valve is stuck open in all 4 cylinders but think that would be unusual.

If so how is best way to free them up without removing the head?
 

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Stuck valves probability high !! With valves stuck in every cylinder there is really no alternative to pulling the head. Hoping to hear a success story - don't get discouraged. Good Luck !
 
I like the look!

Would not be a bad idea to pull the head. Just remove the head nuts, distributor, and hose. Than hit the starter. Head should pop up.

Get it running and safe to drive.
 
Here is some info you might find useful.
 

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Marvel Mystery Oil helps to soften old carbon and iron oxide pretty well. With the head off and all four exhaust valve stuck wide open, you can squirt some penetrant on the stems & guides and get them to move by carefully tapping in the very center of the valve head with a brass drift. Once they start to move then the MMO will work better to open up the clearance more. I usually take the manifolds and the valve cover off as well just to clean all the crap out. If you don't want to go that far then just pull the head but at least pour a quart of oil down through the distributor bore to get something into the valve chamber. It's been a while since the mains were well oiled and it takes the oil pump a bit of time to fill that chamber after the engine starts.
 
Based on my experience, it could likely be all four intake valves stuck open, or also exhaust valves. It could be from rust, or gunk from old gasoline or old oil. If gunk you can remove the valve cover and try a combination of penetrating oil and carburetor cleaner and turning the engine over to exercise the valves. If rust, or if the penetrating oil does not work, you are going to have to pull the head and remove the valves for restoration. No engine will start or run without compression.
 
If rust it may be rings stuck
Then it gets uglier

As an old very wise mechanic said “ there is no mechanic in a can”

J
 
take out the spark plugs,crank engine over looking through plug holes and watch valve motion or lack of it.
I have pushed down stuck valves with a punch for ones directly under the spark plugs.
Also I have used a brake adjusting spoon to lever down the other valve on a car that set under a open porch without manifold
 
Without Removing the Head
Remove manifold, remove valve cover, find stuck valve. Make sure lifter is down....apply heat to valve stem/ guide. Just warm it up a bit. Spray penetrant into port. If you hear a ping, the valve just closed.
You can apply a little pressure to stem or turn with needle nose pliers.
This has saved me lots of time on stuck valves.
I learned to do this on Farmall Cubs.
 
Wick is right. I forgot to mention heat. On the engine I worked on with all intake valves stuck I used a combination of heat, carburetor cleaner, and penetrating oil. Plus a lot of moving the valves up and down. I used a torch to heat the valve guides and stems, being careful not to overheat the springs. Just heated to the point where the penetrating oil was smoking. I worked on the valves for 2 days. This was a straight 8 engine with overhead valves. None of the exhaust valves were stuck which told me that the fuel was evaporating at the intake valve stems and leaving a heavy gunky glue. I added some Sea Foam and Marvel Mystery Oil to the gas tank.
 
Thanks guys, good information, especially the heat to the valve guides and the brake adjusting tool. I will start by soaking the valves with PB Blaster and tapping followed by removing the manifolds and valve cover and heating the valve guides and as a last resort removing the head. I will update everyone on how it goes. Thanks again
 
I worked on an engine with stuck open valves. Easiest and quickest repair turned out removing the head and getting to the valves from above. LRF
 
Kurt in NJ said:
take out the spark plugs,crank engine over looking through plug holes and watch valve motion or lack of it.
I have pushed down stuck valves with a punch for ones directly under the spark plugs.
Also I have used a brake adjusting spoon to lever down the other valve on a car that set under a open porch without manifold
Click to expand...

This. Least amount of work first. Also, can squirt penetrating oil at the valve stem via the plug hole.
 
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