Farmall H Valve Train

Jeff Ferguson4 · Oct 2, 2010

I am working on my Dad's 1940 "H" that has been setting in a barn for 15+ years. Crankshaft turns after soaking in Marvel Mystery Oil but only 1 valve operating. Push rods free and straight. Is this a tappet issue and can it be solved with a complete disassembly?

rustyfarmall · Oct 2, 2010

The valves are stuck in the guides. Spray penetrating oil on the stems, and then lightly tap on the top of the valve stem with a smaller hammer. Give each stem a few taps, and then walk away for awhile. Maybe an hour or so later, do it all over again. Eventually, those valves will loosen up and be O.K.

You will need to remove the rocker arm assembly to gain full access to the valves.

rustred · Oct 2, 2010

well to do it properly should pull head. then pull out all valves and mark them for reassembly. biggest thing is to get rid of that rust in the guide bores. i use a little brush like a miniature baby bottle brush. once you get all the rust cleaned from the valves and guides, you will be very surprised at the clearance you will have now. almost guarantee it will be more than the .003 allowable. rust takes space and wears things rapidly. AND once you have it apart it may be necessary that the valves be ground. there is just no end to fixing old stuff.

Janicholson · Oct 2, 2010

This is what I would do as well. If they start to go down farther, and do not come back up, keep tapping periodically for at least 3 days. Be careful if you try prying up on them while tapping, to not break a spring. Jim

Jeff Ferguson4 · Oct 2, 2010

I previously removed the rocker assembly and can push all the valves down. Only one of the push rods move when cranking the engine. Initially the push rods were frozen but I was able to free them with PB Blaster.

Janicholson · Oct 2, 2010

There is a side plate on the engine that covers the lifters, It is where the oil breather draft tube is mounted. There is rust and or gum on all the lifter bores (except one) Be careful when working on them, if the cam is lifting that particular lifter it will not move down. The cam should be places in the same rotational location as when adjusting valves. Only work on the lifter that is pushing the valve as per the valve adjust. It will take effort and juice but they will come loose. Jim

Farmall H Valve Train

Jeff Ferguson4

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rustyfarmall

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rustred

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Janicholson

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Jeff Ferguson4

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Janicholson

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