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sodium filled valves?

Discussion in '1969-1972 K5 Blazer | Truck | Suburban' started by '72brett, Jan 20, 2003.

  1. '72brett

    '72brett 1/2 ton status

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    Hey, Can anyone tell me what year sodium filled valves were introduced. I bought a blown 350 from a 1980 scottdale. The engine wasn't blown tho and it is now being rebuilt. When it came time for me to grinds valves and knurl the valve guides. the intake and exhaust are different diameters. I called the local automotive shop and they said thats because the exhaust wont wear as fast that way, and they are sodium filled. They didnt know what year this first came about, but they are pretty sure it was later than '80, si I know I dont have the origina engine from that truck. I am just curious, please tell me.
     
  2. '72brett

    '72brett 1/2 ton status

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    well, I came back for an answer. No replies yet I see, COME ON GUYS! someones gotta know this. Or was maybe the shop wrong about the sodium? If anyone isnt sure, I can mail you a valve and u can try cuttin through the middle of it. THEN you can tell if there is sodium in the middle. Im afraid to try. I dont wanna blow myslef up! or burn anything. sodium burns when contact with air. For all you chemistry impaired people. I was told the sodium helps disapate all the heat from the exhaust. This reduces wear in the valve.
     
  3. Triaged

    Triaged 1/2 ton status

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    I could be wrong but I don't think they ever put sodium filled valves in a small block. They are quite common in big rigs.
     
  4. Roostr84

    Roostr84 1/2 ton status

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    The first I recall hearing about sodium or maybe it was phosphorus filled valves was on the LT4 engine about 95ish.
     
  5. '72brett

    '72brett 1/2 ton status

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    alright, thx, but I still dont know why these valve are differnt than other 350s I've worked on. The diameter of the exhaust is much larger than the intake. I suppose I will hit up another forum and ask them. I just didnt do the knurl job on the exhaust, cause I dont have the equipment for that diameter.
     
  6. Roostr84

    Roostr84 1/2 ton status

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    The exhaust valve is larger than the intake? Wow that is really bizare I have never encountered that before. Are there any more specifics on the motor like casting numbers etc?
     
  7. Steve_Chin

    Steve_Chin 1/2 ton status

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    Roostr, stems, not heads...

    Brett, sounds to me like the heads have been worked on before and somewhere along the line an exhaust valve or three seized in their guides. Sounds like the machinist reamed the guides over-sized and installed valves with stems to fit.

    FWIW, I have seen sodium-filled valves that had normal nominal stem diameters.
     
  8. Roostr84

    Roostr84 1/2 ton status

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    Doh,
    Good call Steve see what happens when you don't get enough sleep. Oh well sorry for the misunderstanding.
     
  9. '72brett

    '72brett 1/2 ton status

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    yes, that could be, it was obvious that this engine had been worked on. including the heads. It had after market oil umbrellas on the stems. I just broke em off and put stock back on. The wear wasnt very bad, so I didnt bother in buying new tools to knurl them, just put it back together as it was.
     

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