Tonight I took the old valves from my 468 and tried to pick them up with a magnet. The stems would not adhere, but the tip did. Do all valves do this? Are stock valve stems magnetic, or do none of them stick to a magnet? If a tip sticks, but a stem doesn't, does that mean the stem is stainless, and the tip ordinary steel?

The tip is hardened steel. The stem and head is stainless. Steve

Some valves are one piece, some two-piece and some three-piece if I remember right.

As well as some hollow and filled with sodium metal. Some are made out of Titanium.

And some are made out of Inconel too, pricey little buggers

pdq67

300 series would not be magnetic, 400 series is slightly magnetic but i dont think they make valves with that, stellite, titanium, and inconel would not be magnetic. (those materials are sometimes jokingly referred to as "unobtainium" in the aerospace industry since they can be so hard to find on short notice; and like pdq says "pricey little buggars") it makes sense that the tip would be carbon steel since it would likely have better wear resisitance than the stainless but the stainless would handle the extreme heat of the chamber much better. i was not aware that they made valves with combined materials but you could certainly do that and it would result in a much better valve, (i.e. combining the wear and heat resistance.) you learn something everyday. :)

Stellite valves too! Also pricey..

pdq67