Farmall M Head

Russell Dewsnup · Mar 4, 2015

Finally go to the bottom of my problems with the head on this tractor. The head is a distillate head with gas head valves in it. Problem now is they installed step head pistons, so they are hitting the head when they come to the top. I am trying to figure out what head will replace the distillate head. The parts book shows 8574DCX for the gas head using casting # 8060DD. Will this work for the engine I am working on? The head that came off the tractor engine has casting # 8777-DA. Any suggestions where to find a head for this engine? Thanks

dej(Jed) · Mar 4, 2015

I don't know here you are located, but John at Burgh Implement in Pa. will have a head. Call him at 724-452-6880.
Tell him John C said to give you his discount. he can ship it to you.

D Slater · Mar 4, 2015

Don't have a distillate head to compare. But from what I remember the combustion chamber openings are not much different between the gas M head. Depth of combustion chamber is the most difference. Would want to make sure there's not another problem before buying a head.
What type of step head piston? where are they contacting the head? Didn't install them backwards did they?

pete 23 · Mar 4, 2015

I used to put high altitude pistons (step head) in those old M's and H's to get the compression ratio up where a gasoline head with flat head pistons would be. Never had any hitting the heads but have heard that some brands will.

Gary Mitchell · Mar 4, 2015

I'd figure out how much needed to come off and get the pistons ground down that far, IF, they were a good fit otherwise. gm

rustyfarmall · Mar 4, 2015

(quoted from post at 10:08:00 03/04/15) Finally go to the bottom of my problems with the head on this tractor. The head is a distillate head with gas head valves in it. Problem now is they installed step head pistons, so they are hitting the head when they come to the top. I am trying to figure out what head will replace the distillate head. The parts book shows 8574DCX for the gas head using casting # 8060DD. Will this work for the engine I am working on? The head that came off the tractor engine has casting # 8777-DA. Any suggestions where to find a head for this engine? Thanks

From what I can gather from the original parts catalog, the various heads should be fully interchangeable. Shouldn't matter if the pistons are flat top or step head. If your step head pistons are hitting on the head, you probably have the wrong pistons. Or maybe the pistons are not installed correctly?

randy hall · Mar 4, 2015

if the step head pistons are installed properly and hit the valves they must have over an inch and a half step. m+w sold pistons with a one inch step to use with low compression or high compression heads and they clear fine.

Russell Dewsnup · Mar 4, 2015

I found that only one piston is hitting. It is catching the very edge of the step in one spot. Will it hurt to grind a small amount off the head to make it fit?

Cas · Mar 4, 2015

Theres is an M head on ebay.

rustyfarmall · Mar 4, 2015

(quoted from post at 14:27:31 03/04/15) I found that only one piston is hitting. It is catching the very edge of the step in one spot. Will it hurt to grind a small amount off the head to make it fit?

My opinion----it would be better to grind away part of the piston. Pistons are less costly and easier to get than a head.

D Slater · Mar 4, 2015

Is the piston contacting the combustion chamber deck edge on the opposite side from the spark plug? Could you let us know the brand of pistons?
Pistons ideally should be the same weight for all 4 cylinders and the combustion chambers the same CC. If hitting the sharp edge of the combustion camber I asked about above you can round that edge off a little. Maybe do all 4 chambers the same. May loose a little compression but don't think any performance will be lost.
Unless the piston is obviously made with the raised area different than the other pistons. Saw some aftermarket pistons with the top not clocked correctly with the pin holes. Would send them back if so. Sometimes the head castings can be a little off also. Lay a straight edge down the edge of the combustion chambers to see if any one looks cocked compared to the others.
If hitting head where I asked about there's another option. A 400 or 450 head would probably work without hitting and give you more power. They have a sloop on the combustion chamber edge and I'm guessing your piston step isn't very high.

Farmall M Head

Russell Dewsnup

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dej(Jed)

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D Slater

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pete 23

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Gary Mitchell

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rustyfarmall

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randy hall

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Russell Dewsnup

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Cas

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rustyfarmall

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D Slater

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