What The Hell Are Sodium Filled Valves And Why Do They Matter?
Sodium filled valves have been a mainstay in high performance engines since the 1960s but what do they do exactly? Well as someone with access to Google and a little time to waste I found out and wrote this just for you.
So why fill the valves of an engine with sodium? Well the short answer is sodium helps with the dissipation of heat. The valves in your engine are exposed to a lot of heat due to the explosions they endure during the combustion process. Since we all know heat kills horsepower anything to cool the engine is a welcomed addition.
Typical valves are solid metal and are simply designed to endure to bombardment of an internal combustion engine. Somewhere along the line a very intelligent man or woman figured out that if you partially filled a valve with sodium and left a hollow space you could use sodium to cool the valve.
These sodium filled valves follow the same cooling principal as a human's ability to sweat. The solid sodium in the valve has a very low melting point (97.72C) and high boiling point (883C). This means the liquid sodium that condenses at the bottom of the valve near the combustion chamber boils off to the top of the valve when properly heated. This process of evaporation dissipates heat from the combustion process cooling the engine.
The sodium at the top of the valve eventually condenses back into a liquid forming a sort of rain cycle right in the valve of your own engine! Sodium filled valves are a pretty neat innovation that I took for granted. Now I know they actually do matter!