Platinum Plugs

[rawaudi@frugal.com (RWheeldon)]

Brian said:
>I was always under the impression that copper plugs are better. This is 
>because they are less eficient at conducting than say, platnum. So it 
>takes a smidge more juice to produce the arc, more juice eqauls a hotter 
>spark. 

My impression of why platinum is used in plugs was to allow the tip to run a
MUCH hotter and reduce fouling.  Platinum has a substaintially higher
melting temperature than copper and thus erodes slower even at higher tip
temperatures.  Less fouling + slower errosion = longer plug life.  As for
conductivity, both electrical and thermal, copper is a much better conductor
than platinum.  No comment about racing applications; no experience.
Bob Wheeldon
Principal Engineer
Boeing Commercial Airplanes
robert a wheeldon@boeing.com
rawaudi@frugal.com