John Deere 'D' Stuck Valve?

Hi,

First let me start off by saying I am by far NOT an expert on John Deere tractors, or for that matter, anything mechanical. I can fix things if I have clear instructions and everything goes according to plan. That being said, I have a 1938 John Deere 'D' that my dad re-built in the early 1980's that had lost it's spark. I had the magneto gone through by a friend of my wife's Great Uncle, both of whom donate their time to a local antique machinery museum. While we were putting it on today and trying to get it set right, my wife's uncle said that there was no compression on the flywheel side of the engine, as there was no hissing of the petcock as we turned the flywheel, nor could we feel any suction or air pushing out as the piston moved. It's just basically "dead". The other side seemed to operate as it should and you could both hear and feel the compression as the air moved through the petcock. No question the pulley side of the engine has compression.

My question is if anyone knows of a way we could try to free the stuck valve without having to pull the head off of the engine?

A little background on the tractor:
Like I said, my dad re-built it in the early 1980's, with the help of our neighbor, who started working for John Deere as a mechanic in 1939, and was still working for them at the time of the re-build. Now, we could very seldom start the tractor by hand, but we could pull it a few feet and it would pop right off and run like a charm. Dad never finished the paint on the old girl, so it never got started alot, but we would usually get it going a couple of times a year. After he passed away in 2008, I continued to start it once a year, but it seemed to run a little more roughly each year, until a few years ago when it wouldn't start at all. The gas tank had some rust and crud in it, so I ended up taking that off and cleaning it out, and putting a carb kit in it. This summer I finally got it together, but there was no spark. That brings us to where we are now. We put the magneto on today, and we have spark, but like I said, no compression in the flywheel side cylinder. Any help or ideas would be greatly appreciated as I would really like to finish what my dad started. Thanks.

There is a small sheetmetal cover on the bottom of the head that can be removed, it's used to adjust the valves, and you could probably try to free yours there too.

There are also two pipe plugs on top of the head that can be removed to lubricate two of the valves, I can't remember if they're exhaust or intake...probably exhaust.

Brandon

I have unstuck a few just by getting a pair of channel lock pliers (water pump pliers) and getting hold of the end of the valve stem and twist it and it pop right out or in. may want to tap it with a small hammer to wake it up. Good luck.

(quoted from post at 10:21:45 10/19/16) There is a small sheetmetal cover on the bottom of the head that can be removed, it's used to adjust the valves, and you could probably try to free yours there too.

There are also two pipe plugs on top of the head that can be removed to lubricate two of the valves, I can't remember if they're exhaust or intake...probably exhaust.

Brandon

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Awesome. I noticed both the sheetmetal cover and the plugs and were wondering if that's what they were for. Thanks for the info!!!

(quoted from post at 13:55:47 10/19/16) I have unstuck a few just by getting a pair of channel lock pliers (water pump pliers) and getting hold of the end of the valve stem and twist it and it pop right out or in. may want to tap it with a small hammer to wake it up. Good luck.

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Thanks for the info. You'll have to help me out a little here. Can I get access to the valve stem through the sheetmetal cover mentioned in the above post? I'm guessing I can. I'm hoping it won't take much to free them as it hasn't been that long since it has run.

Well, I believe I got it!!! I took the cover off the front of the head and tapped on the push rod, which seemed to move the valve a bit. I then turned the flywheel, and would have compression for that time around, but evidently the valve would stick again. So I was able to spray some Kroil up onto the valve stems and this seemed to keep them moving. The valves themselves would have been near impossible to tap on with a hammer as they are in there above the push rods, and with just the cover off, there isn't alot of room to work. Also, I don't know how I could've gotten a pliers on them, partly for that reason and also because of the valve springs, unless I'm missing something???? But in any case, they are now free and hopefully we will get some decent weather before the snow flies and I can give it a pull and see if I can get her running again. Thanks for the help.