Quick question on cold plugs and head temp.

[GTLabs]

This is my first air-cooled application that I'll be running around on. Cold plugs put more heat into the head. How big of a window do I have with that, exactly? So far with a BPR7ES plug @ .029 it idles great and pulls very well. I gave it a run on the stand in my garage and it raps out immediately to that little 3000rpm governor ut: :hammer:. I can step down a lot colder and it should do even better. But, shouldn't I hit a heat soak wall of some kind with a colder plug?

 

[-BUCK-]

I would just take it for a spin and pull the plug and look at it. If it has a nice tannish color and no sign of detonation, I would just leave it at that. I would think if you went too cold, it would just start to run crappy before you ran into any kind of cylinder head heat issues. Just my 2 cents. I'm pretty new to these engines as well so hopefully someone will chime in that can answer your question better.