Paul,
With all due respect. Your
guess is wrong. I was there, I saw what I saw. I've seen the damaged parts and
what's left of the plugs. I've been building and working with hi
performance engines most of my life. Your O-235 is not the standard of
all aviation engines. Anyone that thinks aviation spark plugs and auto plugs
are exactly the same, except for the socket used to install them, should not
be using auto plugs. The application design is far different, the heat range
is far different. Aviation engines and auto engines are designed for two
completely different uses. They run at different RPM's, different loads,
different ambient pressures, different ignition systems, different timing,
different fuels. If all spark plugs were exactly the same there would only be
one spark plug on the market.
If your airplane's worth is
a mere $1.67 per plug, then I wish you well. But the first time you witness a
very well built, hi performance Lycoming lose a cylinder over a
$1.67 auto plug, I bet you'll stop using them.
When I'm flying over 200kts
down the so cal coast at 50 feet, I like the peace of mind that the parts in
my engine are designed for and time tested for aviation use.
Anyone that wants to run
whatever they want is fine, that's why this is called experimental.
Randy
Stuart
LNC-2
----- Original Message -----
Sent: Tuesday, May 27, 2008 3:54
PM
Subject: [LML] EI, plugs,
detonation
Randy: I think what you mean is pre-ignition, not
detonation, to take out cylinders. Severe detonation may cause peening of
the top of the piston, broken ring lands, or cause hot spots which could
result in pre-ignition, but it is usually the incredible temperatures and
pressures associated with pre-ignition that will "hole" pistons. (See
Contact! magazine issue 57 for a comprehensive treatment of detonation and
pre-ignition). From your description I would hazard a guess that what you
saw resulted from incorrect timing and mixture. My O-235 is 9.7:1, and I
have dual LSE Plasma Is; My $1.67 Denso plugs run so clean, with no
electrode wear! And my coils are on top of my
engine!