For those who have ordered stainless steel valves...

[Joe K]

Originally Posted by Afordman31

It is call a interference fit!

Um. You have the thought, but it actually results in a "near line" seal. The valve disk is thus brought to contact the "outermost" radii of the bevel in the block, and holding this small angular difference increases the "contact pressure" in that annular seal area.

Forcing the seal to the outer edge of the valve bevel helps prevent "burning" of the valve disk edge, erosion of the block seal area, and makes for "better seal," all of which makes it work correctly "longer."

One of my critiques on valve seat inserts is they introduce an additional "joint" - which impedes heat transfer to the block. But valve seat inserts are also much more durable than the cast iron under this duty - and generally seat inserts are considered "state of the art" because of this.

Joe K