I thought about machining a pressure chamber but my thoughts are that the pressure in an engine gets over 1000 PSI during the combustion process. I think that the air is only about 150 PSI before the fuel is burned/combusted. Air is a dielectric and the higher the pressure the smaller the spark! At least that is what I was told in university. That is why we use vacuum to increase the spark in a gap. In a vacuum tube, electron flows easily as there is no gas to inhibit the flow. In my aircraft we pressurize the magnetos, if we did not when flying at high altitude the magnetos would ark internally causing catastrophic failure. My final thought on the pressure is this…high compression engines use higher voltage and closer spark gaps to overcome the gas dielectric.

I did not notice any difference in the color of the spark…or type of spark. So I don’t think that this spark plug was anything special. I truly was disappointed in what I saw…as it did not look like it was the X amount that they promised in the brochure. I did not feel that making a pressure chamber at that time was worth it… Jetijs let me know if you are going to machine a chamber…I don’t have the tap to thread one.

I just thought of a simple test…I have seen spark plug testers in the past.

Autolite Aviation Spark Plug Cleaner and Tester from Aircraft Spruce

I even use to own one of these things…lol. But I sold it not that long ago. Most airports have them as you need to test the spark plugs every 100 hrs on an aircraft. The only problem is I don’t live near an airport anymore. I will think about where to find one of these machines.

It would be interesting to see if the spark is better under pressure than an ordinary plug.

I paid 25$ each also and about 30$ shipping.

Karl