Sodium Filled Valves on 3.2

[MotoSook]

OK..I'did a search...really I did

But! I found conflicting evidence. One well respected member says that 3.2's did not come with sodium filled valves. I found that say they are..and I seem to recall that some 3.2's did have sodium filled exhaust valves, so didn't. The only way to tell is to look for a dimple on the fact of the valve...where sodium was poured, then the valve sealed.

So! What's the final word gang?

[ghnat]

Mine have the dimple, so sodium it is, at least for me.

[JeremyD]

I thought that after 1980 - or somewhere like that - all 911 engines came with sodium filled exhaust valves - from BA's book...

[Jim Garfield]

I have read that all 3.2 s had sodium filled exhaust valves to reduce weight and dissipate heat, and that the CS also had hollow intake valves to reduce weight.

[MotoSook]

My search (OK..I admit..I didn't look it up in my references..but even the references have been said to be incorrect on this mater) led me to doubt......especially since a well respected Pelican made a strong statement saying they weren't sodium filled.....

[randywebb]

I've read or heard what JG posted....

Some actual work is indicated:
1. Compile printed sources - Frere, BA, Ludvigsen, etc.

2. Find out what the "usual suspects" have seen:
Steve W./Gamroth organization
Jerry Woods
TRE
Grady
Sherwood
Warren
various other machine shops and engine builders...

[masraum]

I thought I had read in Paul Frere or BA's book that the exhaust were and club sports had the intake done to, but someone, can't remember exactly who, has repeatedly corrected me on this. His argument seems sound, I just believe him and haven't doublechecked.

[MotoSook]

I'll pull all my references this weekend...yet, I'm afraid they won't all agree

I guess I'll jsut cut a valve in half! Don't make me do it! Don't! I'll do it...really I will.

[Bill Verburg]

This thread is a prime example of why I am becoming more and more disenchanted here

Every one seems to have chimed in w/ their opinion, I have posted before about this but am not believed, that's ok, But for gods sake guys if you don't know, either look it up or don't post!

No normally aspirated 3 or 3.2 liter had sodium filled valves, w/ one exception and one almost case. The 3.2 liter Carrera C/S had hollow intakes(930 105 409 13 used to be ~$40/ea dearer than the std Carrera intakes) and the SC/RS had Na filled exhaust ala the turbos.

Please take the time to look it up on your own. It's in all the shop manuals and parts books.

The 964 N/As used sodium but in the intakes not exhausts.

The 993RS was the only one to use sodium in both intakes and exhausts

[MotoSook]

Bill...so the dimple check is not reliable?

[Bill Verburg]

I don't know what is meant by a 'dimple'

These are 993 sodium cooled intakes





The onlu manufacturing artifacts that I see are
1) a small ring visible on the hardened tip
2) the tuliping where the shaft and head are joined

[MotoSook]

The "dimple" which is now "urban legend" is on the face of the valve (toward the combustion chamber) on sodium filled valves.

If the only manufacturing artifact is the tuliping, then we have to trust the books. A visual inspection would likely be unreliable.

One urban legend exposed! Thank you Bill....don't lose patience. You've been overly helpful on many topics that make coming to Pelican so addictive...

...I'm a skeptic and you have to hit me on the head with a 5 lb sledge of fact to knock it home...better to be skeptic than a passive sponge

THANKS!

[randywebb]

Wouldn't any dimple be ground off?

Note - it was not disbelief - it was failure to do a search first. (Probably the only time in the history of this bbs that has ever happened).

Souk - you uare going to post the page numbers of the shop manuals Bill mentioned, aren't you?

Of course, a real skeptic would not trust the shop manuals - instead they would design a statistically valid test to sample valves from all over the world, stratified by country....

[MotoSook]

Randy...I'll post info.

And I couldn't afford to be a real sketic ... but I did search; however, I found conflicting info....

Now! I hear that sythetic oil is no good for air cooled engines..is that true?

[Bill Verburg]

Here is a better one of the stem


and the face, no sign ofdrilling would be seen here as no drilling would be done here

[MotoSook]

I don't have a picture of my 3.2 valves, but there is a dimple of face of the valve....some what like the one in this poor quality picture I found in a thread search...(Not trying to steer this thread onto a tangent, but this is the so-called dimple indicator...you see it on the 3.2 exhaust valves)

[Bill Verburg]

As I said no drilling would penetrate the valve face

[randywebb]

"I couldn't afford to be a real sketic"

- that's why you apply for research grants...


- You know I've seen those little dimples too. No idea why they are there - maybe a manf. artifact?

[JeremyD]

From Wayne's Engine Rebuild book.

[Paul T]

Not that this is relevant at all, but I know the exhaust valves on my 356SC are soduim-filled.... always thought all 911s were too, but it seems there are inconsistencies in the factory manuals.