Cub valve stuck

[waynemo]

I am still working on my Cub with a stuck valve. I will next try to start it boy pulling with fresh gas and additive in both gas tank and crankcase.
Which is the best way to lube the valve and guide. Gas tank or crankcase with lubes? How does valve guide get its lube in operation? Seems to me that more lubrication takes place in the block via the crankcase. Your thoughts?

[waynemo]

I meant pulling it with another tractor.............

[Glen]

Hi,
If a valve is stuck open, you will probably need to loosen it up before it will close.
Running the engine will probably not make it close. It will just stay open, there is nothing to make it close.

Remove the valve cover on the left side of the engine, and see which valve is stuck.
Use spray penetrating oil and lube the lower end of the valve stem, it is inside the valve spring.
Pull the valve down with a screwdriver or pliers, and keep working it up and down and see if it loosens.
The valve has to close by itself every time it is opened.

If it won't loosen so it closes by itself every time it is opened, probably the best way is to remove the manifold, then you can get to the upper end of the valve stems, spray the upper end, and the oil will run down the stem.
Keep working the valve until it is free.
It may need to sit with the penetrating oil on it.

After the valve is free working, put motor oil on the stem.
You could put motor oil on all the valve stems, if you have the valve cover or manifold off.

TM Tractor at the bottom of the page has new gaskets, if you need them.

Below is a page from the Cub service manual, showing the oil circulation in the Cub engine.
It shows in the lower left pic that the oil pump oils the valve lifters, and it looks like the valve stems just get splash oiling.

http://www.farmallcub.info/manuals/gss- ... 001-53.jpg

They have said on here to pull a Cub by hooking to the drawbar at the rear of the Cub, and running the cable forward to the hitch on the truck or whatever is pulling the Cub.
Don't pull on the front axle, it can break.

[Bigwally30]

I start with the easiest, pull the spark plug and lube the valve from above. Turn the engine, if the valve sticks tap it down. Tap and turn until it frees up. You may have to pull the valve cover like described above.

[inairam]

I would not try to start it until the valve is free.

[NJ Farmer]

You are most likely going to have to pull the head and remove the valve and ream the guide…..sounds like a lot but the hardest part is getting to the part to remove the head since the hood needs to be removed. If it is above your head I understand but if the valve is sticking there is a reason why…the clearance is too tight.

NJ Farmer

[inairam]

there is a reason why…the clearance is too tight.

NJ Farmer

or there is crap in there closing up the clearance. you can work the valve up and down and hit it on the top and bottom with your favorite penetration oil without pulling the head. This would be my first effort. Pulling the head can have a lot go wrong and leads to "while the hood is off " and "while the head is off" project creep.

My goal is to get them running and use them so I can identify what needs attention before I just start just doing stuff and replacing parts.

[waynemo]

I plan to pull the tractor to get started with sea foam and mystery oil in the gas and crankcase and let it run for a couple hours to try and loosen the valve. Last fall the valve stuck after running for an hour or so. I pulled the hood and managed to get oil on the small area I could see and got the valve loose and it started everytime on the first crank. I went out every day or so and started it up for a couple weeks lately. So I took it out and sickle mowed for an hour and half and shut it off to raise the sickle bar and it did not restart. The valve must have stuck again!
Thanks for the diagram that seems to show the valve lifters, guides, and valves are splash oiled. Would it help to increase the oil pressure by adjusting the pressure regulator to get more flow coming from the crank? Don't understand why it stuck right away after running for an hour and half. You would think it would get looser after running hot for that long.
I will resume working on it when the weather cools a little. Weather is a problem to me as I am too old at 85 and handicapped with parkinsons. Glad to be able to get help from you guys here on this forum!