John,
Your right on re: the sodium cooled valves... used them on Hi performance engines in the USCG in the 1970's.  I also installed them in a 1974 Mercury Capri (German Ford) 2 liter four.  The valves preformed beautifully in combination with several other mods that resulted in one very hot running four banger...
GregK
"seadog"
  ----- Original Message ----- 
  From: John Rodgers 
  To: vanagon@GERRY.VANAGON.COM 
  Sent: Wednesday, January 10, 2001 12:13 AM
  Subject: Re: True cost of AMC heads for 1.9L and 2.1L: bare for $240 to$216!

  Sodium filled valves are used fairly extensively on bigger piston type aircraft engines. It's purpose is to aid in the dissipation of heat from that portion of the valve that is in the combustion chamber (valve face) up through the valve stem into the rocker space where the valve stem contacts moving oil which scavenges the heat and transports it to the oil cooler or other cooler parts of the engine. 
  No reason to think it wouldn't be desirable on smaller engines as well. Even our beloved Wasserleakers. 

  John Rodgers 
  88 GL Driver 

  Dave Baker wrote: 

    Sodium-filled valves.  There's a neat concept.  Can anyone tell me why they would want to do this? Dave in KC (who is learning tons of new stuff from the members on this list!)85 Westy http://members.fortunecity.com/davebaker1/westy/westy.htm 

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