cracked M head

Got a queston every M we have tore apart in school has a cracked head. Can you preasure check them and if they don't leak put them back on ? I am sure a lot of these tractors are running around with cracked heads.

I had a head repaired once and they die test it with pressure to find the leak. So ya you can test it. I have not done it my self. oldiron29

I have seen one fail a pressure test that then got magnafluxed and was fine...explain that.
Yes, they can weld the crack. If you already have it that far apart just take it in and have the crack fixed.

the best is pres. test with water and if no leaks, use it. you are correct, there is a lot with cracks and not leaking.

Yes you can have them pressure checked and welded. They will pin and weld them and then pressure check them. This prcess can be a little pricey as it needs to be done by a machine shop to be sure it is square again. and done correctly. As for putting it back on if it is cracked I suppose you could if it check out ok but I would have some reservations about doing it. The reason that I would is that as the engine runs there are extreme pressures on that head and in turn that crack. Even in these old engines running stock there is at minamuim 55psi on a compression on each cycle of that piston. At 1650rpm thats a lot of times that the crack sees the crack sees pressures on it in a short time of running. If it is a gas motor I would look to see if you could find a good used one or a remanufactored one. As by the time you you have a shop do this right is close to finding a good used one or a remaned one. Diesel are pinned and welded all the time as they are not nearly as easy to find and not nearly as cheap when you do. I would tell you to either have it done correctly by a shop or to find a different one as I am sure that you dont want to go in the engine again anytime soon. Have a good time redoing the old girl. You will enjoy yourself and it is good to see some younger people involed in old tractors. If you have any questions feel fre to ask or email. I have been bitten by the Farmall bug a while ago. I have a few of them around here.

Jason

Call these guy's. If its for school maybe the will cut you a deal

http://www.midwestcylinderhead.com/index.php

What do you mean by cracked, and how are you determing this? I just want to verify that you arent looking at casting marks or something.

we take the heads to a shop and have them cleaned and magnafluxed

I had the head from my 1940 M rebuilt at a shop several years ago. The head was not leaking, it just needed all new valves, seats, and guides. The shop looked it over, and he found several cracks, but he told me not to worry because there is no such thing as an M head that does NOT have a few cracks. He went ahead and did the rebuild, I put it back on the engine, and everything is just fine. Didn't leak before, and it doesn't leak now.

Let me guess, the cracks are on the sealing surface?