Robin van Spaandonk wrote:
In reply to Stephen A. Lawrence's message of Sun, 13 Mar 2005
21:53:10 -0500:
Hi,
[snip]
absence of the sharp edges. That, in fact, is the biggest part of what happens to "old" plugs -- since they tend to fire at the sharpest corners, those corners eventually get rounded off, charge distributes itself evenly over the (now smooth) surface, and the firing voltage must be consequently a great deal higher. With a modern high voltage system that may not matter much but in the old days of a single set of breaker points, a capacitor, and a coil, plugs with rounded off corners had a very hard time firing.
So, the notion that he just filed off the sharp edges on a conventional plug and _improved_ its performance is very hard to swallow. It makes the subsequent claims that much harder to believe.
[snip] You may have "indirectly" hit the nail on the head. :) If a modern high voltage system has no problem with it, then more charge will probably build up before the spark jumps, which may imply a bigger spark. That in turn will probably result in a more sure burn.
Hmmm -- good point! Didn't think of that! The whole (old-fashioned) sparkplug design was done for systems that had to struggle to get past 10,000 volts when the engine was running at speed; with more headroom maybe that same easy-to-fire design just gets in the way of producing a fatter spark.
There is also the matter of the cage that he built
around the outside, which you haven't taken into account.
Sure; I was just commenting on his first experiments with old-style plugs.
(If the fuel air mix isn't perfect, then a small thin spark may occasionally be "igniting" mostly air, and fail altogether for that cycle).
Regards,
Robin van Spaandonk
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