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RE: Ignition and sparks

To: <mgs@autox.team.net>
Subject: RE: Ignition and sparks
From: "Matt Endicott" <endicar@comcast.net>
Date: Sun, 29 Jan 2006 20:32:45 -0600
I've sold spark plugs for over 20 years and am always taken aback by the
term
"hotter spark".  What exactly do you mean?  A spark plug is designed to work
within a specific heat range for that specific engine.  If it falls below or
above that temperature you will either have a fouled plug or you will lose
control of ignition timing resulting in erratic running and likely engine
damage.  If by "hotter spark" you mean more current then that's an issue of
coil type and spark plug gap.

The principle reason newer spark plugs have multiple ground electrodes is to
maintain the gap and service life of the plug to meet warranty and emissions
standards.  Most electrode wear occurs on the ground electrode.  Spreading
that wear over 2, 3 or 4 ground electrodes substantially increases gap life.
Use of metal with better erosion and corrosion characteristics benefits the
center electrode in primarily in terms of longer life.  When the spark
occurs it always seeks the path of least resistance.  It only sparks to ONE
electrode, never more per laws of physics.  There are some engines made to
use more than one plug per cylinder to ensure there is complete combustion
to meet emission requirements.  There have been some special race plugs made
that actually have two center electrodes within one plug shell, but unless
your name is Andretti you won't be running them in your MG.

BTW the nology plugs are silver electrode Beru spark plugs...yes the same
ones that used to be pink.  Bosch Silversports are very similar.  There are
lots of well made plugs today.  Personally, I run Bosch Silversport W7DSR in
my 948 Midget and have for years.  You won't find them in the retailers, but
Peter C can help you.....sorry for the "plug", but I couldn't help myself.




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