Quote:
Originally Posted by skeeter
How can I tell if my valves have been replaced with newer stainless steel style? I just removed the head and attached a magnet to the valve. The magnet sticks to the valve but I don't know if it's because it's a low grade stainless or an old style steel valve. Is there a way to check? Any comments or concerns would be appreciated.
Skeeter in South Jersey
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It is only partially true that a magnet will stick to a lower grade of stainless.
Stainless steels, like all steels, come in various alloys. Stainless alloys fall into three classes based on crystalline structure; Austenitic, Martenistic, and Ferritic. Each class has many different alloys within it. Of the three classes only Austenitic alloys are non-magnetic. Most automotive valves are made using a Martensitic alloy and are therefore magnetic. While it is true some of the cheaper alloys fall into this class, i.e. the type used for automotive exhaust systems, there are many other alloys within this class that are by no means "cheap" yet are still magnetic. In short: Using a magnet to test for alloy is probably not the best way.
If the valves are serviceable use-em.
Tom in SoCal