Tecumseh valves too tight / no clearance issue?

[Fordiesel69 270]

Im repairing tons of techuseh engines (77 in total) and am finding people on youtube say that due to poor manufacturing the valves do not have enough clearance / lash, so you had to remove them and grind the tips.

 

My kohler and briggs experiance was always the opposite, when you have TOO MUCH gap, and need to gring the seat and face to tighten up the end gap.  

 

How common is this, and why are the getting tight instead of loose?

[pfrederi 18,406]

K181 KT 17 ad Magnum 18 non adjustable you grind the tip of the valve stem to get  more gap...

[squonk 42,885]

Those valves can get tight from seats wearing in the block and the valve faces wearing or neck stretching.