Scott:
That's a nice cutaway. In their manual The Aviation Spark Plug, Champion
shows a cutaway of a hot plug and a cold plug. Unfortunately, one plug is a
long reach and one is a short reach! All the aviation mechanic texts copied
this cutaway. This causes students to think that a long reach plug is cold
and a short reach plug is hot, or whichever way it was shown.
In actuality, reach has nothing to do with heat range, only with the
thickness of the cylinder head where the plug hole is.
It took alot of explaining to get them to understand the difference between
reach and heat range. Why Champion used that stupid cutaway I'll never
understand!
Thankfully, the cutaway on your link shows both plugs with the same reach.
John Herrera
>From: "Barr, Scott" <sbarr@mccarty-law.com>
>Reply-To: "Barr, Scott" <sbarr@mccarty-law.com>
>To: <fot@Autox.Team.Net>
>Subject: RE: Hot/Cold Plugs (was Interesting message)
>Date: Tue, 26 Oct 2004 12:37:52 -0500
>
>Jim said: << If you could cross section a "hot" plug you'd see the
>ceramic is a long thin cone with the contact point to the metal far up
>the spark plug body. A "cooler" plug has more ceramic and contacts
>down closer to the electrode.>>
>
>Aha. There's a good diagram of what Jim was describing at:
>http://www.howstuffworks.com/ignition-system2.htm
>
>Scott
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