Farmall M Head Gasket R&R

PAvegfarmer

New User
Bought a 1951 Farmall M a couple of weeks ago to do some hay work on the farm and also to double duty as an eye catcher at my vegetable stand. The tractor had been sitting for a year with a blown head gasket and the motor was seized. Got my hands on it before the guy loaded it on the scrap truck.

I got everything unstuck and cleaned up real nice. The head looks good, the sleeves are not pitted or corroded, cylinders look good as well. I am now getting ready to put it all back together. I was wondering if anyone on here has the sequence for torquing the head bolts. My repair manual has 110 ftlbs but no sequence. Sound right? Also any recommended adhesive to use on her, I was going to get the copper permatex. Also anything else to inspect while I have it all ripped down. This is my first trip inside a Farmall and just looking for some general advice. Thanks in advance.
 
Others will have more and better ideas, but I would definitely
look at the sleeves to see if there is a "ridge" at the top, which
would indicate that the sleeves are worn. I was told to torque
the head bolts in a spiral sort of pattern from the center outward
and to step the torque up, maybe in your case something like
torque all to 70, then to 90, then to 110. That is supposed to
result in better sealing or something. I have done an H and a
300 with those methods and both seemed to be fine afterward. I
used copper coat, don't remember who made it but I am sure it
is the same as the permatex stuff you mentioned.
Zach
 
PA, was there a ridge on top of the sleeve? did you hone? Good time to put in new bearings and rings if it needs it. Copper coat on the gasket.
totque I start about 60# work center to outside
up 10# ata time till 110# oldiron29
 
The gasket would be best if coated on both sides with Copper Coat spray gasket sealer.
The pattern is to get them all in place, touching the head, then start in the center set of fasteners (front to back) and tighten them to 10 Ft pounds.
then using an "X" pattern continue outward to the extremes. Repeat the pattern at 50 ft pounds, then 75, then 100, then final tightening. Button it up and adjust the valves. Put hi-tack gasket sealer on the cover side only of the VC gasket, this allows it to be removed easily. Get it running and allow it to stabilize in temp. (15 minutes) then retorque the fasteners and reset the valves to hot spec (it does not need to be way hot, could be able to hold your hand on it is fine, but not 60 degrees). Jim
 
the sequence is just start in the middle and go around in a circle till done. torque in three steps. i would do 40, 80 and then 110 ft lbs.
the adhesive i use is permatex high-tack sealer. it is oil and gas resistant and holds the gasket in place. i have never had a reason to use coppercoat other than on bolt threads. many do use it on head gskts. thats another thing, make sure the stud threads are lubed with coppercoat, or neverseize lube. also once you get it running retorque the head and re -adjust valves to .017 once run for an hr. or so at half throttle. do adjustment while engine is still warm.
have you removed valves from head and checked guides and valves and seats. also make sure no rust in guides. check the head for warpage with a straightedge also since it had a blown gskt.
 
Check your ring end gap at top and middle of bore. Plastigage onthe rods and main bearings.
I use the copper spray for heads.
 
At 110 ft-lbs torque, you do not need a sealer. Use grease. This will allow the gasket to spread out/move as you torque it in the spiral pattern described by others. I would go in 10 ft-lb increments after 80 ft-lb.
 
Thanks for all the advice. I took a good look at the sleeves and there is a slight ridge. I will have to get a good measurement on it later. There is no play in the piston at all that I can tell. I will drop the pan tomorrow and take a look at the bottom. The head is still within specs according to the ol' straight edge.

I plan on only doing light work with this tractor and 90% of the time it will be for show. Do you think I can get away with new rings? Maybe have a go at a complete rebuild in a couple years. This is my budget tractor (my wife made the budget, not me), so far with a new head gasket set, a used manifold, battery, and everything for a tune-up I am in it around 900. I wanted to get it done including paint and decals for under 1200.

However, I have never seen this tractor run and don't know much about variances in the M. Any go or no go opinions on when to do this? Or how long they last with some sleeve wear doing light work?
 

I checked the head with a straight edge and it looks good. I think the gasket went because it wasn't torqued properly. Some of the bolts were barely on. They came off with a tap on the wrench and finger power.

The cylinders and pistons were carbon free except for number 4 which must have had a combustion problem. The valves were completely out of whack so that probably had a lot to do with it. It didn't appear that anyone had been in the engine a long time and I guess they must have worked themselves off.
 

Yes there was a ridge...I commented below on when to or not to re-sleeve. I'll take a measurement on the ridge tomorrow. No piston play though that I could tell.
 
it will run longer than you as is. a little ring ridge is no big deal for someone on a budget. a rule of thimb is if you can hook your finger nail on the ridge its overhaul time.
from what you describe i would bolt the head on and enjoy cause the paint will eat the rest of your budget.
 
If you do not change the rings, there is no issue with the ridge. I and others assumed you had the engine apart. If not, and the oil pressure was ok and it sounded good, run it don't take it apart. Jim
 

Thanks Jim. I meant I just have the head off. I have never heard this tractor run. Just going off of the word of the previous owner. He said it ran good until the gasket went. Then he let it sit and once it seized he didn't want anything to do with it.

I'll put it all back together and run her. Thanks for all the advice.
 

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