Sodium Valves? Options

[stugray]

I was once told by one of the resident "experts" on this forum (who has not been around lately) that I should replace my sodium filled valves with stainless. However after visiting the local RSR racing mechaninc (who is machining my case and inspecting my heads), HE said that he goes out of his way to FIND sodium filled valves for race engines. He said that on Air-cooled engines, the sodium helps pull the heat from the heads.

Any comments or suggestions regarding sodium vs. stainless?

I also heard that a simple change from two-angle to three-angle valve seats can increase flow by more than 20% with no other changes to the heads.

Good news is that I should be re-assembling the engine without the deck height problems over thanksgiving weekend. Hope to have it running by Xmas. (IMG:style_emoticons/default/piratenanner.gif)

Stu

[gothspeed]

As long as the engine is well maintained and not abused you should be fine. The sodium valves installed by the factory in the past had a bad reputation of dropping the 'valve head' into the combustion chamber. However I am not sure if there was any abuse or neglect involved in those cases. But if you keep track of your valve adjustments regularly, you will get a fair warning if the stems are stretching before they would actually fail.

But as mentioned above ........ newer SS valves are inexpensive, plentiful and reliable.

[barefoot]

As long as the engine is well maintained and not abused you should be fine. The sodium valves installed by the factory in the past had a bad reputation of dropping the 'valve head' into the combustion chamber. However I am not sure if there was any abuse or neglect involved in those cases. But if you keep track of your valve adjustments regularly, you will get a fair warning if the stems are stretching before they would actually fail.

But as mentioned above ........ newer SS valves are inexpensive, plentiful and reliable.

Just into rebuilding newly acquired 2.0L 914 heads with the 3 stud intake manifold.
I gave the valve heads a few raps with bronze mallet just to see if any were stuck closed prior to pulling valves. One spring suddenly popped up higher.
here's what i found, a fractured stem. Close examination appears to be a brittle fracture with no indications of "beach marks" indicative of progressive fatigue fracture.
See photo.
This would dispel above "stem stretching" as failure warning.
I'll scrap this set of sodium filled valves.
I'm presuming any hollow stem valve is of the sodium filled variety as i have no history on these heads. I'll try to get NEW sodium filled valves, but will go with stainless if can't find hollow stem.
Any good sources for new sodium valves???

[Keyser Sose]

I don't think you're going to get a more eloquent and convincing argument against sodium filled valves than this:

.
Usually that's the part of the valve you have to dig out if the shattered piston after the POS came apart at high RPM's. In chunks. I'm sitting here thinking, and can't come up with one good reason to use them. Not one.