O.K. I did a search and didn't find anything on these spark plugs. Has anyone heard of or used the E3 Diamond Fire spark plug? I am getting ready to put them in my Zenoah GT-80. It is a direct replacement for the Champion RCJ7Y. They are guaranteed not to foul for life. I got them at the auto parts store. The choice was these or autolights.

Shan

I bought one of these plugs, ran it on the ground and it did fine. Then I realized it didn't have an "R" in the name and I became concerned about RF interference so never flew it.

That would be my only concern and for all I know, it may be a resistor plug...just didn't indicate it anyplace I found.

If you have a multimeter you can check for resistance in your plugs by placing the leads on the center electrode and the terminal on top. If it is non-resister it will read very close to 0 ohms. I checked several small engine resister plugs and they are showing about 22k to 24k ohms. One was a brand new Champion RJL19LM still in the box. I checked one non-resister I had for my old race car and it showed less than 1 ohm. If I had sanded the coating off the terminal end it would probably have been 0. If the E3's show high resistance like this I wouldn't hesitate to use it.

I finaly got a chance to fly and there was no problem with interference. I range checked and then flew. The engine ran better than it ever has. I was very pleased. The only problem is the plugs are about .25 inch too long. The cowling fits real tight and the spinner does not line up straight.

My Zenoah twin came back from Rcign last spring with NGK BPRM6F plugs installed. I like these as they are smaller and shorter than the Champions usually used in these engines. Cheap to replace too at about $2.00 each. Should last for years so I don't believe that fouling or replacement should be an issue. Also a good fit in the shielded EI plug lead caps.