I made this large dumb model of a spark plug.   It does nothing other than be large.
Print the pieces in PLA, and then glue it together.    

I've included the .stp file if you want to mess about with it or add different logo artwork.

It's scaled to be as large as you can make it on a A1/X1/P1.

I have designed a display stand for this, but I'm waiting until I can print and test it before I upload it.   I will let you know when it's complete!