Sodium Valves? Options

[JFJ914]

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

To paraphrase Jake, You are the designer of the engine, you are responsible for your decisions. Go for it and let us know how it works out. If it works out, great. If not you can start your own pile of shame parts just like Jake. Good luck.

[brant]

another thing I don't see mentioned in this thread....

finding used stock valves won't work if bigger valves are intended.
most race motors go with stainless and also bigger valves

as mentioned, stainless are available and affordable (in a large variety of sizes)
I've run (used up) 3 different race 2.0/4's with stainless and bigger valves.
never dropped a valve or seat in those 3 motors.
(of course I had a great head builder for them also)

[worn]

another thing I don't see mentioned in this thread....

finding used stock valves won't work if bigger valves are intended.
most race motors go with stainless and also bigger valves

as mentioned, stainless are available and affordable (in a large variety of sizes)
I've run (used up) 3 different race 2.0/4's with stainless and bigger valves.
never dropped a valve or seat in those 3 motors.
(of course I had a great head builder for them also)

I just bought a set of new sodium valves. Not a big expense - less than the taps and plugs for the oil gallery threading. I bought them because I like the idea of a heat transfer system within a solid valve, and because they use sodium as a coolant in some nuclear subs, and because of the urban legend when I was in chemistry at the University of Washington that someone had tossed half a kilo of sodium metal into the major pond/fountain in front of the building to see the fireworks. If you want dependable maybe a Toyota? A metal that spontaneously catches fire? C'mon, where is the difficult part in this equation? (IMG:style_emoticons/default/bye1.gif)

[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???

[Mark Henry]

A lot of the sodum is better crowd info is coming from the 911, it has bigger 9mm sodium valves that work good. I suspect they are a higher quality valve to start with. They do use lower pressure springs because they don't have to push the extra weight of the pushrods and lifters.

Type 4 I'd use new soduim if you can find them, but often I convert the 9mm exhaust valve to a 8mm quality SS unit. Never seen any issues in doing this.

[Jake Raby]

The worst failures I've ever seen have come from Sodium filled, hollow stem valves.

Not for me... And we've had one stainless valve failure in the last 15 years.

[bulitt]

(IMG:style_emoticons/default/agree.gif) Sodium corrodes steel. Only a matter of time.

[brant]

The worst failures I've ever seen have come from Sodium filled, hollow stem valves.

Not for me... And we've had one stainless valve failure in the last 15 years.

I agree. Thousands of race miles at high rpm with stainless. Zero problems

[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.