Mailing List lml@lancaironline.net Message #47454
From: Randy <randystuart@hotmail.com>
Sender: <marv@lancaironline.net>
Subject: Re: [LML] EI, plugs, detonation
Date: Wed, 28 May 2008 20:55:32 -0400
To: <lml@lancaironline.net>
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 -----
From: Paul Lipps
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!
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