Re: Iridium sparkplugs

[Jon Pike <jhpike@domain.elided>]

> melting point higher then Platinum, electrical resistance lower then
> platinum.  This may allow the use of a projected electrode where a
> non-projected nose was necessary with a lower melting point electrode
I followed a link passed along earlier, which linked me to the NGK site, 
and a section on their Iridium plugs.

Yes, a very thin projected point..  The resistance aspect can hardly 
make a difference in this application, a half inch of metal is going to 
have a few tenths of an ohm resistance, and maybe a few hundreths less 
than the same length of Platinum..  when you have resistor plugs with 
10,000 or more ohm resistors inside, for reducing RFI, and that dosent' 
bother the spark.

But, if the melting point is higher, you could make a thinner tip, and 
have it last longer in the same enviroment.  And, that thin tip should 
be easier to strike a spark across, so it would be a perhaps noticable 
difference.

Hey.. it's nice when something turns out to be not all hype!

Jon
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