Mailing List lml@lancaironline.net Message #47459
From: George Braly <gwbraly@gami.com>
Sender: <marv@lancaironline.net>
Subject: RE: [LML] Re: Electronic ignition spark plugs
Date: Wed, 28 May 2008 22:26:54 -0400
To: <lml@lancaironline.net>
 
All of those people using automotive spark plugs in their high performance aircraft engine, please make yourself known and - - -  tell the rest of us what the temperature is of  ceramic insulator of your automotive spark plugs when the engine is  operating under high power hot day certification conditions?
 
Please!  Step forward and give us the hard numbers?  
 
                   *********    long pause for reality check ***********
 
I can tell you the answer to that question with respect to an aviation spark plug.
 
But unless somebody has measured it - - you really don't have any idea  - - -  do you?
 
And keep in mind that 25 to 50 degrees "too hot" can make all the difference between "OK"  and pre-ignition disaster as some have experienced.
 
That fact that ANYONE has experienced a pre-ignition disaster due to an automotive spark plug - - - is a VERY good reason for everyone else to NOT use those plugs until SOMEBODY has measured the ceramic temperatures.
 
Regards,  George Braly 
 
PS.  It is  REALLY hard to get a valid signal from a  thermocouple in a spark plug inside a cylinder and to get a valid reading when the thermocouple is sitting about 1/8th inch away from an electrode that is discharging 25KV about 22 times each second.  Really.  It can be done.  But it is not for the faint of heart.
 


From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of Dominic V Crain
Sent: Friday, May 23, 2008 10:15 AM
To: lml@lancaironline.net
Subject: [LML] Re: Electronic ignition spark plugs

 

1. Consistent large gap.

 

2. Small electrodes that don't block the flame.

 

3. Great spark exposure to F/A mix (see 2).

 

4. Electrodes don't wear.

 

5. Great endurance.

 

6. Can you go wrong with a well designed moped plug? Nah!

 

7. Cheap - merely US$ 11 per plug (I use Denso IK27 with my Light Speed Eng. EI).

 

SOLD!

 

Thanks Grayhawk

 

Cheers

Dom

 

 

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