>If I end up using these plugs full time later, I will consider Lynn H's

>suggestion to remove the eyebrows on the block, but really like to know

>why Mazda went to the trouble of putting them on before grinding them off.

 

         Simply looking at the eyebrows, they seem to serve no purpose

other than to make it impossible (or at least very difficult) to put in a

13/16" type spark plug. Perhaps this is their intended purpose.

 

That is exactly their purpose.  My understanding is that the chief concern was the risk of a piece of broken insulator from an unshrouded plug finding its way into the combustion chamber.  I expect to replace plugs on a more frequent basis to reduce that risk.

 

It’s looks to me like it would take more than removing just the “eyebrows” to use a stock socket on the B9EGV, especially on the leading plugs.

 

Al