Sodium Filled Valves

[K5DH]

Sodium is some dangerous stuff! No wonder my cardiologist wants me to take it out of my diet. . .

[51fixer]

Stupid question but visually any way to tell the difference on a 1300 Radial intake and exhaust valve that are new in an unmarked cardboard box? They came in years ago with a donation of engine parts.

If you have an overhaul manual it should give dia of the stems on the valves and the same for the large od.
Exhaust valves usually have a bigger stem dia than the intake but the manual should tell you.
Do new 1300 parts have value? They didn't make a ton of them and I don't think many are around.
New parts might be helpful to T-28A owners.
Thought I would throw that out there.

[seaknight15]

AS and old 1820 mech Don't mess with them . Bad things happen If messed With.

[oscardeuce]

4Na+O2= 2Na2O
For sodium oxide
2Na+O2= Na2O2
For sodium peroxide

2Na +2 H2O=2 NaOH + H2

I would assume the amount is small enough that assuming the shavings don't flash, throwing the broken part in with other oily parts equals a fire. I don't think a big explosion, but after hours the parts bin catches fire.
Was a chemist in my misspent youth

Like was said the safest place is in a large body of water, or immersed in oil. Na is stored under oil until used. The water reaction is typically more impressive, but will spontaneously burn in O2 environment.

[carlisle1926]

I had several hundred used large sodium filled valves in a box. Most of them had a domed shaped head and if you shook them, you could hear the powder rattle around inside like a salt shaker. I knew not to cut on on them with a torch for art projects, I just didn't know why. I must have sold a ton of these things to people as souvenirs! OOPS.- but I did warn them not to cut on them.

[pjpahs]

The Mythbusters did a part where they remotely dropped metalic sodium into a toilet or some other container and it did "explode" when contacting water. Lots of sparks etc. I found on youtube a guy with a cut apart sodium filled exhaust valve from a Audi 2.7 V-6 engine , and he was putting it in and out of a container of water with his bare hands and all it was doing was fizzing, it could be faked, I don't know. Is the sodium used in valves of a mix of chemicals? Tried to find out thru Google but it must be some secret recipe from the valve makers.

[N77657]

Could someone explain the concept behind using sodium in valve stems? When did they first come into use?

Bill

[airnutz]

Could someone explain the concept behind using sodium in valve stems? When did they first come into use?

Bill

Sodium-cooled exhaust valves is your clue, note page 6...
http://www.enginehistory.org/OX5to3350.pdf

Lotsa good reading in the Engine History site, and the onsite search feature works pretty well. Cvairwerks has a nice bit of P-66 techno saavy in his noggin...good to know.

[Fouga23]

Just came across this:
http://www.youtube.com/watch?v=FK-HA_5mAAI
Shows the reaction pretty well :/

[BAJ]

.
Could someone explain the concept behind using sodium in valve stems? When did they first come into use?...Bill


Found this Bill:

http://forums.turbobricks.com/showthread.php?t=247000

Basically it appears that as the valve opens the sodium "slops" down into the valve head and rapidly absorbs the heat from combustion then as the valve closes the sodium "slops" back up into the hollow valve stem taking away the excess heat with it from the combustion chamber area.

[B 25 C]

In high school back in 1964 we had a demonstration from our science teacher. A very small pinch of sodium dropped in water caused a very big explosion with a very loud bang. Don't mess with it!