What are sodium filled valves used for?
Sodium filled valves represent the latest discovery aiming at granting the durability of the valve train and are produced by drilling the valve stem and inserting a sodium bar allowing to dissipate the heat generated in the combustion chamber through the stem, the head and the seat.
What are sodium filled exhaust valves?
The technology of hollow and sodium-filled exhaust valves is used in motorsport and in high-performance engines. The sodium filling prevents overheating of the valves and allows the engine to operate at higher exhaust gas temperatures.
When were sodium filled valves introduced?
The poppet valve was invented in 1833 by American E.A.G. Young of the Newcastle and Frenchtown Railroad. Young had patented his idea, but the Patent Office fire of 1836 destroyed all records of it.
What causes valve stem damage?
Wrong lubricating oil grade. Overloaded engine. Too much cold running under a light load. Oil seal failure – leading to formation of excessive oxidised lubricating oil on the valve stem.
What are two basic types of valve seals?
There are two basic stem seal designs – deflector and positive seals.
What is intake valve and exhaust valve?
Intake and exhaust valves are responsible for controlling the flow of gases through the combustion chamber. Intake valves let air in, whereas exhaust valves let air out. They are shaped to have a slim stem leading to a flatter face, with the intake valves often being larger than the exhaust.
What are the possible causes of a burnt exhaust valve?
One of the most common burnt valve causes is an ineffective seal between the valve and valve seat. Burnt valves occur when the valve can no longer seal correctly after excessive temperatures have damaged the material of the valve. When this happens, combustion gases are able to escape.
Which valve is used in IC engine?
The valves used in the IC engines are of three types: Poppet, mushroom valve, Sleeve valve or Rotary valve. Of these three types, Poppet valve is most commonly used.
What could cause a valve stem to wear in one area?
Possible causes include an incorrectly set valve clearance − or the valve seat insert or valve guide were not remachined centrically. An excessively large or small valve guide clearance can also have fatal consequences.
Should you lubricate valve stem seals?
The amount of oil that passes by the valve stem seal must be precisely controlled. Too little oil causes stem and guide wear; too much oil causes carbon buildup leading to valve seat damage, decrease in volumetric efficiency, increased emissions, catalytic converter degradation and excessive oil consumption.
What kind of valve is filled with sodium?
Sodium-filled valves are hollow and partially filled with liquid sodium.
What should the temperature of a sodium filled engine valve be?
If the head is hollow, the valve temperature will average only slightly exceed 600 degrees. Best cooling is achieved when the stem cavity is filled with sodium. When cold, the sodium in the tree is gaseous, but as the valve heats up, its gaseous state becomes liquid.
How does sodium move through the valve stem?
Thus liquid sodium only partially fills the cavity of the valve stem. As a result, liquid sodium in the valve stem cavity can move through the handle – from the valve head to the opposite side, ie. to the handle. With this movement, sodium transfers heat from the hot valve head to the handle.
Which is the lightest sodium filled exhaust valve?
In a sodium-filled exhaust valve, 40 percent of the cooling is through the stem so the valve can tolerate more heat. Titanium valves are the lightest valves available, and typically weigh about 40 percent less than stainless steel valves of the same size (with solid stems).