 Sodium filled exhaust valve, Do I have one |
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| ruddyboys |
 Jul 22 2004, 12:10 PM
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#1
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Hummel eigentümer  Group: Members Posts: 594 Joined: 3-March 04 From: Monroe, NY Member No.: 1,749 Region Association: North East States  |
Does anyone have a pic of what the sodium filled exhaust valve look like. I have to pull the engine to replace a valve spring, again, so I figured I would replave a exhaust valve the has a little damage to the top.
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| Jake Raby |
Jul 22 2004, 12:35 PM
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#2
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Engine Surgeon Group: Members Posts: 9,394 Joined: 31-August 03 From: Lost Member No.: 1,095 Region Association: South East States |
Sodium filled valves have a very small dimple right in their center, its maybe 3-4mm diameter.
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| Dave Bell |
Jul 22 2004, 12:47 PM
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#3
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Member Group: Members Posts: 234 Joined: 27-November 03 From: Santa Clarita, CA Member No.: 1,398 Region Association: None |
I don't have any pictures, but there is a nice summary of the multiple advantages of the Sodium filled valves at.
http://www.ganioglu.com/supar/sodyum/sodium_filled.htm Reminds me of a MIG/TIG welding class I took about a year ago.. someone had donate a couple boxes full of partially finished and blank titanium valves and other students had welded some together as practice material... what a shame! There were still lots left though... an man were those babies light. - Dave |
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| ruddyboys |
Jul 22 2004, 12:53 PM
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#4
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Hummel eigentümer Group: Members Posts: 594 Joined: 3-March 04 From: Monroe, NY Member No.: 1,749 Region Association: North East States |
Mine don't look like these from PP.
Attached image(s) 
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| Jake Raby |
Jul 22 2004, 01:56 PM
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#5
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Engine Surgeon Group: Members Posts: 9,394 Joined: 31-August 03 From: Lost Member No.: 1,095 Region Association: South East States |
No benefits of Sodium valves in the Type 4! Not that i have seen...
Nice explosions though :-) |
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| Demick |
Jul 22 2004, 02:18 PM
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#6
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Ernie made me do it! Group: Benefactors Posts: 2,312 Joined: 6-February 03 From: Pleasanton, CA Member No.: 257  |
QUOTE(ruddyboys @ Jul 22 2004, 10:10 AM) I have to pull the engine to replace a valve spring, again, I would think that you should be able to replace a valve spring with the engine in the car. |
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| Allan |
Jul 22 2004, 02:22 PM
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#7
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Teenerless Weenie Group: Members Posts: 8,373 Joined: 5-July 04 From: Western Mesopotamia Member No.: 2,304 Region Association: Southern California |
Any reason why you can't go with stainless in a stock motor? Reliability issues?
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| Jake Raby |
Jul 22 2004, 02:34 PM
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#8
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Engine Surgeon Group: Members Posts: 9,394 Joined: 31-August 03 From: Lost Member No.: 1,095 Region Association: South East States |
Stainless is BETTER than sodium!! I build 20,000 buck engines with stainless valves! (they are severe duty valves, however)
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| Dave_Darling |
Jul 22 2004, 02:37 PM
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#9
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914 Idiot Group: Members Posts: 14,990 Joined: 9-January 03 From: Silicon Valley / Kailua-Kona Member No.: 121 Region Association: Northern California 
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The valves in the photo do not appear to be sodium-filled.
Jake has never seen a benefit to the sodium-filled ones, but he does not build stock engines. Porsche decided that they were a good idea to help keep the exhaust valves from burning. They help transfer heat from the valve face through the valve stem to the valve guide, and from there to the cylinder head where it can (hopefully!) be radiated away to the cooling air. I myself would strongly consider the sodium-filled valves on a stock motor. If, however, I were paying a pro (e.g., Jake) to build a motor for me, I would listen for his advice and pay attention to his recommendations for that specific motor. --DD |
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| Allan |
Jul 22 2004, 02:56 PM
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#10
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Teenerless Weenie Group: Members Posts: 8,373 Joined: 5-July 04 From: Western Mesopotamia Member No.: 2,304 Region Association: Southern California |
I have spoken to several different shops about going with one or the other and it seems to be about 50/50 either way. Based on the experience of builders like Jake and others, dosn't it make sense that if stainless works well under the rigors of racing that they would do well for street use? (IMG:style_emoticons/default/confused24.gif)
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| bperry |
Jul 22 2004, 03:59 PM
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#11
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Lurker Group: Members Posts: 477 Joined: 16-February 04 From: Dallas, Tx Member No.: 1,661 |
I have no idea where I originally heard this but,
I always thought that the purpose of the sodium was to enhance valve cooling by using the phase changes of the sodium changing back and forth between solid and liquid states. I thought the theory was that it went liquid during the combustion cycle then at some point before the next combustion cycle it turned back to solid. Since it consumes quite a bit of energy to change states that you got a slight cooling effect for free as the sodium transitioned back to solid state. It always sounded like a good theory. Maybe it only works at low engine speeds like at idle? and is only needed when running hotter running cams like the stock FI cam? That would explain why racers would never see any difference. Anyone else ever heard of this? --- bill |
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