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Farmall M Engine

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IAtractorKid

Member
OK guys, my aunt finally got her M over to me and I was able to check it out a little last night after getter the Farmhand loader pulled off. She said that it keeps fowling the plugs and is hard to start and runs rough. It looks like oil is weeping out of cylinder 3 from the exhaust manifold and from the head gasket on the other side of the block. I pulled the plugs and cylinder 3 was dripping with oil...the others weren't too bad. She was told to use Autolite 388 plugs, I'm guessing that is hotter than the 386 that I'm thinking it should have? I was VERY shocked with the compression numbers of 130, 122, 140, 125. What do you guys think at this point? Initially I was thinking valves or rings but with compression numbers that high...would it maybe be valve guides instead? Either way I know I'll have to pull the head and pan to inspect and measure everything for wear. Just curious what you guys would be thinking at this point. 46 M with I believe an F4 magneto.
 
I think it gets run fairly hard...its their main tractor for cutting/bailing hay. That's a possibility though! How would I check that?
 
Add a quart of ATF instead of a quart of motor oil with a new oil filter and high-detergent motor oil. Work it hard a couple hours, making sure you get the tractor up to operating temperature and keep it there. Pulling a 3-16 or 4-14 plow, for example. Make her snort.
 
the 140 psi cyl. is most likely from being carboned up. how much oil is the tractor using? should know that as can very well be rings and sleeve wear.
you don't need to pull head to check guides, just valve cover.check each cyl. on tdc. any noticeable looseness can be felt by moving top of valve side to side. its not accurate but still gives you an idea of the really loose ones causing grief. meaning that if no noticeable looseness is there then you saved pulling head.as compression is ok. to get rid of carbon in head run tractor at fast idle at operating temp and sniff in water at carb .you can even buy spray in stuff for this. also make sure the carb is set after u adjust valves and points and timing. then do as steve says, work it hard. then monitor the plugs to see if there are burning the regular brownish.
 
Cutting/baleing hay is not hard enough (sustained)work.It needs to be put on a plow and worked the snot out of for a day or so.2-4 hours is better than none......
 
Ill try and get out in one of the neighbors fields next weekend if he hasn"t worked them already. Ill change the oil and substitute in a quart of ATF. Are the 388 plugs ok or should I change them out to something else?

Also, with the loader removed, I have no reservoir for the live hydraulic pump...can I just run a line from the drain plug of the belly pump to supply the pump and return to the fill hole on the belly pump? It will just be a continuous loop but at least it will have fluid!

Thanks for the help guys!
 
If it is slobbering that much oil it should be smoking. Leaking valve guides usually get better when it warms up good. When you get it warmed up does the exhaust clear up? I had one with very bad leaking guides. I put foulers on the plugs and ran it up to temp every time I used it. When it was cold it looked like I was burning brush. When it was warmed up there wasn't any smoke at all. It seems people will throw new parts at the block but put the same old head back on it when they button it up.
 
I dont know if it smokes when being worked but it didnt smoke at all yesterday when I started it up, drove it off the trailer or around the shop. Guess I dont know if all the fowling on the plugs is oil...just assumed it was based off what she had told me and all the oil on the block around the head gasket and manifold at cylinder 3.
 
I can't help with the plugs.

You will be ok using the drain hole and the fill hole for hydraulic fluid if and only if you have hydraulic fluid in the reservoir - or at least non-detergent oil. If you have detergent motor oil in the reservoir you will get a lot of foam.
 
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