I was just wondering If anyone could tell me about spark plug heat range. This is a shady subject for me and I am looking to learn something here. OK. How do you know when you are in the right heat range, what testing/ techniques do you use to verify your heat range. I have read that If the insulator is white then you are good to go, is this the only way to tell? Also, when doing mods to a motor, how do you know when It is time to change your heat range? Are there any rules of thumb for determining this? What are the effects that plugs of different heat range will have on a motor. I know if you are constantly fouling plugs then you probably need a hotter plug, right?? When is a plug too hot and how do you tell?? OK one more thing about plugs... What are the benefits and differences of say different types of NGK plugs? For example BR8EV vs. BR8ES vs. BR8EG, etc?? I undersrtand about resistor plugs and their function, but all this other stuff has me stumped. Any help would be appreciated.

 

here is a link it should answer all your questions it is a pretty good readNGK

 

Thanks Alpine2.