Speedo
FOUNDER
TN
I just read an article on Bring A Trailer written by a fellow who owns a Citroen SM with a C114 engine. Interestingly, the C114 has sodium-filled valves.
Per the article, the valves are prone to rusting from the inside out if the engine is kept in a humid climate and used infrequently.
My knowledge of metallurgy is a tad limited, but I don’t understand how a sodium filled valve can rust from the inside out. Surely rust-causing water can’t have gotten into the valve during manufacturing or at a later time while sitting in a humid environment. A water/sodium reaction is quite energetic, and would likely destroy the valve abruptly rather than gradually. Possibly the sodium is reacting with one of the components of the valve steel, I suppose.
So I doubt the article’s author is correct, but I figured our experts here would know more about sodium-filled valves and the possibility of their rusting from the inside out. Can anyone shed some light on this?
Per the article, the valves are prone to rusting from the inside out if the engine is kept in a humid climate and used infrequently.
My knowledge of metallurgy is a tad limited, but I don’t understand how a sodium filled valve can rust from the inside out. Surely rust-causing water can’t have gotten into the valve during manufacturing or at a later time while sitting in a humid environment. A water/sodium reaction is quite energetic, and would likely destroy the valve abruptly rather than gradually. Possibly the sodium is reacting with one of the components of the valve steel, I suppose.
So I doubt the article’s author is correct, but I figured our experts here would know more about sodium-filled valves and the possibility of their rusting from the inside out. Can anyone shed some light on this?