Reply To: Cracked valve seats

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Bob Koch sent me an email to question my statement above where I wrote that the valve can actually carry heat away from the block. I was incorrect in my comments. The valves do not cool the valve seats in the block, rather the valve face is cooled by the block/seats.

What I really meant to convey was that the poorer thermal conductivity of the stainless material will result in less heat travelling down the valve stem to points cooler in the engine. To cool down during the intake and compression strokes of the engine, the valve needs to dump heat down the stem, and through the seat. The typical austenitic stainless which we refer to as 304 or 316SS are about 50% as good at conducting that heat as the older ferritic steel valves which Pierce originally supplied. Bottom line is that stainless valves will run hotter valve head temps.

I appreciate Bob’s comments and offer the above.