Spark plug problem

I have the electroair ignition on one side and am having premature spark plug failure (<100 hr on several plugs). When I test these on a regular spark plug tester, they seem to spark just fine but I notice they are sparking/shorting in the barrel of the plug on the tester. Brand new plugs do this a little bit but not nearly as much. The question is whether this is a valid way to test these plugs with the wider spark gap. Of the plugs I removed from service because of apparent failure, I notice a brownish discoloration of the ceramic around the lower end of the barrel. Also not sure if this is significant. Input from others with experience or advice appreciated.

Maybe a different temp plug?

Switch to an auto plug.

rvdave said:

Maybe a different temp plug?

Click to expand...

+1

If you search on the web, you will find charts with a range of different colors for deposits on the ceramic along with causes as well as heat ranges. You likely have too cold of a plug and therefore the deposits are not burning off as they would with the proper heat range. Carbon-based deposits on the insulator will form an electrical path to the shell and allow the spark to bridge there instead of the negative electode, usually with a weak spark.

For a well running engine, you should have nothing darker than a very light tan color.

Larry

I also have installed an electroair ign. I assume the plugs you are speaking of are attached to the EI, not the mag. I am using massive electrode obtained pre-gapped from electroair. I have around 500 hours on them thus far and they still look great. The color is light tan as it should be. I am using REM37HE plugs.

Based on what I see on the spark plug tester, i.e. sparking up in the barrel of the failed plugs, I suspect the problem is with the funky spark plug terminations and my inability to get the little springs installed correctly. These plugs have probably been shorting in the barrel as a result. What type of wire termination is used for the automotive plugs?

The auto plugs use different terminations and possibly new wire. The spring needs to be pushed into the end of the wire so it runs next to the carbon thread, not in the middle of the thread. I believe there is a video on this.