Spark plug shorted electrode

Friends,

Performing a mag check for flight today I discovered rough running on my Emag side. Upon further check of the gauges it showed a cool No 3 cylinder so off with the cowl. I pulled that cyl spark plug and sure enough the electrode was shorted out. It looked like a piece of carbon had welded the electrode tip gap shut. I cleaned it off, regapped, put it back on a vroom everything good now.

I had just installed new NGK BR8ES plugs not 3 hours runtime previous to this flight doing my airworthiness inspection. I aggressively lean engine on the ground and it has 330 hours since new over 5 years. I had been using the BR8EIX (tungsten) tip plug and change every 2 years-never had this happen to me with these plugs. Thought I would give the BR8ES plug a try and change them every year. Now I am wondering if these plugs are prone to this or what I can expect.

Comments, experiences, advice?

Jim
RV9a
Howell, Mi

Jim,

Anecdotal only: I use the same plugs and change them at each condition inspection. I've never had a plug that looks like it even needs to be changed. I fly about 100 hrs/yr.

700+ hours running BR8ES plugs with dual pMags. Never had anything like this. Typically changed out every year or every other year just because it is cheap and easy to do so.

Carl

Its not the plug, just coincidence. Occassionally carbon buildup chunks break off from various parts of the cylinder/piston. They often bounce around for quite a while before breaking up and passing out the exhaust. Yours just happened to get lodged in the plug gap.

Larry

Thanks for all your responses. I?ll chalk it up to an anomaly. Would that piece of carbon have stuck to the tip of a tungsten electrode?

It?s the first time that I went to go flying and cancelled the flight due to an aircraft or engine problem. It was a quick diagnosis with the GRT EIS.

Jim
RV9a