Sodium Filled Valves on 3.2

[Jeff Alton]

Alright, here we go. Against my better (joke) judgment being tired, sick, suffering from allergies and way behind on my prep for tomorrow's DE, I went and cut some valves.
The 3.2 valve #930 105 419 08 is shown here with dimple and a solid stem!


Here is the 3.6 valve #964 105 419 00 showing dimple and solid stem!



Here they are side by side.



Interesting, want anything else cut up?? I am feeling brave!

Guess this means not all "dimpled" valves are NA cooled! Soooo
maybe the parts books are right after all!

Cheers, Jeff

[Todd Simpson]

Bravo, Jeff!

[RickM]

IMO, you have to cut it in half lengthwise. IIUC, the sodium liquifies when heated and travels up and down the stem to carry heat away from the valve head. At room temp it's solid.

[AES]

Originally posted by RickM
IMO, you have to cut it in half lengthwise. IIUC, the sodium liquifies when heated and travels up and down the stem to carry heat away from the valve head. At room temp it's solid.

Unbelievable! The evidence is staring you in the face and you still don't get it. No wonder people get discouraged with the postings here

Even if solid it won't look the same, and a drop of water would cause a fuss as well

[ChrisBennet]

Reminds me of a phrase that goes something like this:

"Are you going to believe what you've been told or your own lying eyes?"


-Chris

[RickM]

AES, get a life.

[silverc4s]

I believe Sodium metal looks quite different from steel - white chalky appearance IIRC.
Not sure how much of the shaft will be hollowed out for sodium, but in the area of the valve guide for sure, and from there as close to the head as strength requirements permit.
I'd say we are still at sea as to whether any of these valves were sodium cooled. I always thought they were, but now I want to see some authorative reference that gives engine types, etc..

[RickM]

Originally posted by silverc4s
Not sure how much of the shaft will be hollowed out for sodium

Exactly my point. I haven't read one convincing comment on where a valve would be drilled (if in fact they are drilled) when filled with sodium. The entire shaft, part way up from the head...or part way down from the stem tip? What if the cut shown above is just above or below the hollowed out area?

BTW, Jeff, thanks for cutting the two valves.

[ChrisBennet]

I thought that the '69S exhaust valves were sodium filled.
Years ago I asked the guy who does my heads about Porsche's use of Sodium filled valves and he said something to the effect that he hadn't seen it or at least hadn't seen the warning on the valve boxes that usually indicates sodium filled valves (instructions on how to dispose of them?).
-Chris

[silverc4s]

Maybe just the turbo exhaust valves? Is there a unique part # for these?

[JeremyD]

definitely Turbo, definitely 959, and the other models that Bill mentioned.

[Kahuna]

You guys should know better than to argue with Bill V. by now

[thunderdenton]

Thank god they did not have Na in them.

I cut some valves open just to see if they were sodium filled during my rebuild last year. It had been several years since my chemistry classes and I did this with no gloves.... I read this thread and I shiver to think how stupid I was.

This was a 1984 3.2 ROW. So not Na here either.

[randywebb]

drilled?

I'd guess they are made from thick wall tubing bonded to the tulip portion - no idea how manfs. really make them tho. IIRC, the Alfas used them first in race cars.

[Bill Verburg]

Jeff, Thanks very much for cutting photoing and posting. When I get some I'll do a longitudinal cut w/ our 50hp bandsaw.

The same valves from 3 different manufacturers were used from '76 C3 thru '89 Carrera.

Except as noted previously.

The 930s thru '89 did use sodium cooled exhaust valves.

The 964 used sodium filed valves for weight reduction on 964 intakes but not on 964 exhausts(Jeffs pic is a 964 exhaust valve).

993 did the same except 993RS which has sodium in both intakes and exhausts.

Now here's another one that some of you won't believe
The 3.6 liter 964 M64/50 doesn't have sodium filled valves either.

[randywebb]

Interesting. I wonder why?


Sometimes it seems to me that we know more about these cars than the factory does - now.

[Bill Verburg]

Some of the ss alloys are truely remarkable and relatively cheap.

[Jim Garfield]

Originally posted by Bill Verburg
Now here's another one that some of you won't believe
The 3.6 liter 964 M64/50 doesn't have sodium filled valves either.

quote:
Originally posted by randy webb
" Interesting. I wonder why?"



The 964 M64/50 had ceramic portliners fitted into the head before the aluminum was poured which became part of the head. Being bad heat conductors they reduced the head temp by 40 degrees C, which made the sodium filled valves unnecessary.

[randywebb]

That makes sense.

The thing I don't understand is why fill the valve stem with sodium for light wt.? Couldn't it just be left hollow?

[Todd Simpson]

The sodium is not there for weight reduction. It bounces back and forth as the valve opens and closes, transmitting heat from the face of the valve, up the stem and out the guide.

I would guess they are lighter, so there is some advantage, but fully hollow would be even lighter.