Jim in Western MI
Member
While I realize the job that a spark has to do is sorta simple, there must be a lot of complexity associated with them since there are dozens of types of plugs..., or are there (?). My Dad, the real mechanic in the family, was determined to use the one shown in the Owner's Manual. For the 8N that was Champion H-10. Now I cannot even find that plug at NAPA or the other auto box stores, though they all have interchange numbers and several "choices." Some they push as Champions have a symbol on them which is similar to the Champion logo, but it doesn't say Champion anywhere and I suspect they are cheap China copies. Even YT has two plugs for 8N's and other models, one of which seems to replace H-10, 12, 16, and 18; as well as many others. Many here recommend Autolite 437's, which I tried once but they seemed to get carbon chips and deaden a cylinder, but I recognize that could have been happenstance. I am interested in the truth (if there is "truth") about spark plugs, having researched the archives didn't help much. Has all this complexity been overthought and the only thing that is material is the thread size and length to get it in the right place? If heat ranges are important, how does one plug replace dozens of others with multiple heat ranges?