The car plug charts are showing nose temps for what situation? Cruise? stop and go?

And what maximum throttle setting. For a car, 13 to 25 HP is cruise on the freeway.

 

If you wife is with you, you cannot even use full throttle without getting yelled at. So the plugs that stay clean at cruise in you car at 25 HP and 1,900 RPM with an 800 degree nose temp, are likely to do what after one hour of more than full throttle and 6,000 RPM?

 

Well, let us suppose that the nose temp might be quite a bit higher. After boiling the cement out of a few plugs, and even loosing the center electrode out of a few I have determined that the nose temps at full throttle in any car engine might be higher than the plug manufacturer thinks is OK for plug life.

 

 In a piston engine there is a chance that the loss of material from a plug tip might be expelled through the exhaust valve. With your luck, in a rotary, and in an airplane there is no chance at all that this will happen. The rotor housing and apex seals will be destroyed. The remaining power available will barely extend the dead engine glide range. You will be landing very shortly. Punching "nearest" or "save me" on the GPS will just add to your confusion.

 

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