Lynn:

You scared me so I went out and removed the spark plugs. WX too crappy to fly anyway.

The BUR6EQ-L and BUR8EQ-T were installed 9-16-06 and I put 6.0 hours on the plane since then.

The plug color didn't look any different than any other set of plugs I've removed in the past, and the electrodes still looked like new.

I have excess radiator capacity and a thermostat, the coolant temperature as measured at the stock location never varies from thermostat temperature even on an extended full power climb on a hot day. So that's probably why I lucked out and didn't experience any detonation with the hotter plugs. According to NGK only about 70 to 100C hotter than BUR7EQ/9EQ.

I agree with you that this is not a good solution to lead fouling, so the experiment is terminated prematurely. I have 500 hours on this engine, no reason to destroy it now.

I don't fully understand how these plugs get lead fouled anyway, the whole ceramic insulator must get coated with enough conductive lead to short them out.
I hate 100LL and don't even want to burn it, but on long trips it's the only thing readily available. Trying to locate aviation enthusiasts to help me get mogas enroute is a bit of a hassle, but not as much hassle as changing the spark plugs mid-trip. I was successful flying from Oregon to Kansas and back last summer and the summer before with mogas assistance in Utah and Nebraska.
http://www.bridgingworlds.com/k61_2/k61_2_photos.htm
http://www.frappr.com/mogasassistancenetwork

Next question: how easy or difficult is it to install a MSD system on a stock Mazda EFI? I'm going to get one and put it in my RX-7 to find out.

Lynn wrote:

That 1,000 degrees of nose temp is not a limit. Even 800 degrees is not a limit. Those are "kiss your engine good by temps".One episode of preignition and it is over.

 

Since the only way there is to detect plug damage is to damage the plug and then look at it, this will be a very expensive system for determining the maximum heat range. If it takes a set of plugs to make a round trip to Sun&Fun, so what? Spring for the $7.00 and put in a new set. If you get the SAG after even 10 hours, this is a tiny percentage of the cost of flying. Carry 4 new plugs with you and the wrench. How many people have not had coolant and oil temperature control problems on the first flights? This means higher nose temps does it not?

 

Running a car plug at 900 degrees to avoid lead fouling is out of the question. Run whatever Tracy runs. He isn't loosing engines.

 

Lynn E. Hanover