I want to know more in general about spark plugs, the NGK and Champion numbering systems (those are the 2 brands I use), and what sorts of "conversions" between plugs are OK without damaging the engine or creating performance issues. I just found some information on heat ranges, which I think I understand pretty well now. But I don't know, for instance, if it's OK to use a resistor plug in an application that calls for a non-resistor. I did learn that it's generally a no-no to use a non-resistor in place of a resistor, but is using a J19LM in a pushmower OK, even when it calls for an RJ19LM?
I have a Homelite Super XL chainsaw in my shop right now, and the Champion catalog I have calls for a CJ6 plug. I don't have any CJ6's in stock, but I do have a few RCJ6Y plugs. Heat range is the same, thread size and reach is the same. But I don't know what sorts of changes the resistor will make in the engine performance. Also, the Y on the end. According the the Champion numbering system chart I'm looking at, the RCJ6Y has a "standard projected core nose" firing end design, whereas the CJ6 has a "conventional" firing end design. So what does all that mean and what difference does that make?
I know some of you on here know this stuff. What would you recommend I read to become a spark plug expert?