hardened exhaust valves and seats for M

It does a lot of heavy field work, and I have had to adjust the exhaust valves a couple of times because (I presume)of seat wear from unleaded gas.

I am going to buy one of the overhaul complete kits that you see offered. I would like to know if the valves in them are hardened? I am going to take the cyl. head in to have new exhaust seats put in. Do I have to specifically ask for hardened seats from the machinist? Are hardened valves and seats available for M tractors, or are things in the new kits still made of the same metal that was orginally used for these parts? I really appreciate any advice! This is the first time the cylinder head is going to be off in 25 years, and I want to make sure everything is done a-ok before I put it back on again.

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Many times the old valves are recessed in the cylinder head and new seats are needed to allow proper installation of new valves. If recession is not excessive you might opt for hardened seats only under the exhaust valves. I had this done once. The old valves were so deep in the heads my guy could not cut new seats, so he put hard seats under all the valves. Initially, the valves were not deep enough for proper rocker geometry. We finally got the correct depth figured out, he ground the seats a little deeper and it all turned out great.

It is not surprising to see that a lot of these tractors already had hard seats even in 1972.

I always assumed they came from the factory with hard seats on the distillate (no lead in kerosene) models and maybe all of them.

An M may be an antique but it is not crude.