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sodium valves

Discussion in 'Technical Q&A' started by Meister, Nov 30, 2003.

  1. Meister

    Meister F1 Rookie
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    Apr 27, 2001
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    Duluth, MN
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    The Meister
    Over the long WI winter I'm thinkng of doing a little more service on my 80 308. If I'm going to do it right I should change out the sodium valves. But since I don't have kind of service records how do I know if they were ever changed? Can you tell simply by visual inspection, or would you have to take one out to know for sure. Also, where is the best place to get SS ones. Thanks, Scott
     
  2. rivee

    rivee F1 Rookie

    Jan 20, 2002
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    John
    The place I got my ss valves and brass guides, and was told they are the best, is S I Industries in Simi Valley, Ca. (805) 582-0085. Intake and exhaust were $22.00/valve, and guides were $7.82/guide
     
  3. ricrain

    ricrain Karting

    Nov 1, 2003
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    Ric
    I've used SI in the past and was pleased with the products. If you get SS valves, make sure they have the hardened tips!
     
  4. Peter

    Peter F1 Veteran
    Rossa Subscribed Owner

    Dec 21, 2000
    6,340
    B.C., Canada
    The sodium valves have these markings written on the tip (just above the keeper groove): "EL BM ST FS". If its different, you can check by running a magnet along the stem (its not magnetic, but the tip and head are). Most likely they've never been changed. Its a very good idea to replace them, replace the guides while you're in there too.

    I got my valves from Superformance in the UK. Stainless with tufftrided coating and stellite-welded tips and valve-seat rims. Inexpensive.
     
  5. Meister

    Meister F1 Rookie
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    Apr 27, 2001
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    thanks guys!
     
  6. Dr Tommy Cosgrove

    Dr Tommy Cosgrove Two Time F1 World Champ
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    May 4, 2001
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    Wasn't the sodium used to help with heat issues? Did it turn out to just be a bad idea?
     
  7. Mitch Alsup

    Mitch Alsup F1 Veteran

    Nov 4, 2003
    6,337
    Sodium turns into a liquid just above room temperature. When in liquid form, it has high specific heat so it can be used to absorb heat at the combustion chamber and transfer that heat to the valve guide much more rapidly than steel. Thereby reducing the temperature that the steel outer casing has to endure*, and combustion chamber heat also. However, the remaining steel is thinner and is subject to somewhat higher stress (there is less of it--and the same amount of spring seat pressure), so the valve streches and can break with less than optimal consequences.

    *Regular steel exhaust valves transfer most of their heat to the cylinder head through the valve seat. This puts a minimum size for the contacting ring to transfer the required amount of heat.
     
  8. Dr Tommy Cosgrove

    Dr Tommy Cosgrove Two Time F1 World Champ
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    May 4, 2001
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    So did Ferrari stop the sodium valves on later models?
     
  9. Verell

    Verell F1 Veteran
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    May 5, 2001
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    Groton, MA
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    Yes,
    I've forgotten the specifics, believe when they went to fuel injection, but could be wrong. At this point in time, the sodium filled valves are getting pretty brittle and should be replaced if a head is being pulled.

    For lots of details, go to 'Old FerrariChat.com Archives' topic and use it's search capability at the bottom of the page. Several good threads last spring.
     
  10. Dr Tommy Cosgrove

    Dr Tommy Cosgrove Two Time F1 World Champ
    Rossa Subscribed Owner

    May 4, 2001
    28,476
    Birmingham, AL
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    Tommy
    I want to think my 84 308 has sodium valves as well (4 years into fuel injection). Anybody know?
     
  11. Verell

    Verell F1 Veteran
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    May 5, 2001
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    What came up with your archives search?
     
  12. Peter

    Peter F1 Veteran
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    Dec 21, 2000
    6,340
    B.C., Canada
    The real reason for sodium-filled valves was because of the air-injection. If you take a look, the injector nozzles point straight at the valve heads. Air injection obviously supplies ambient air to the oncoming exhaust gas and this helps to oxidise the Carbon Monoxide and turn it into less harmful/polluting Carbon Dioxide. This process creates incredible amounts of heat and therefore needed the extra cooling affect of the sodium in the valves.

    No air-injection, no need for sodium-filled valves.
     
  13. Verell

    Verell F1 Veteran
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    May 5, 2001
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    Peter,

    While your argument is logical, in the thread below JRV was pretty adamant that only 2V engines had the sodium filled valves. He claimed that the 4V valve stems were too thin to be sodium filled, and Ferrari was already having embrittlement problems with the 2V engines.
    Also has a pretty graphic description as to how fragile the sodium filled valves have become!!!:

    http://www.ferrarichat.com/discus/messages/256120/302519.html

    Perhaps Dr. Ferrari, Dave, or another of the professional mechanics can comment also.
     
  14. Mitch Alsup

    Mitch Alsup F1 Veteran

    Nov 4, 2003
    6,337
    I think a different explanation is in order.

    The sodium filled valves are for 2 V heads. When Ferrari when to 4V heads, the valve stems became too thin to allow drilling and filling with sodium.
     
  15. Peter

    Peter F1 Veteran
    Rossa Subscribed Owner

    Dec 21, 2000
    6,340
    B.C., Canada
    Verell, I'm not arguing the fact that QV's had sodium-filled valves, I knew they didn't already and I do remember that thread you posted... :)

    All I said was a reason why they used sodium in the valves and I implied it to the 2 valvers since this was what this thread was about. Sorry if I was not specific. By-the-way, I'm familiar with how brittle the valves are, I've seen a broken one and the damage it did. Ain't pretty.
     

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