Spark plug replacement is interesting to me particularly on cars that I drive a lot. That is because as you say, the condition of the plugs when you take them out is VERY revealing. If the cars just sit around a lot and only get started occasionally without being driven this will tell you next to nothing. Most generic shop manuals give a page or two of color pictures that show what various plug conditions indicate. Paul In a message dated 3/16/2004 9:06:21 AM Eastern Standard Time, kmoore12@xxxxxxxxxxx writes: > Fellow Imperial aficionados, > I have been "listening" to all the discussions and comments on spark >plugs and thought I should throw in a couple of my pennies. Recently, I have >been fooling around with my timing trying to get rid of some pinging. The only >way I could get rid of it was by retarding the timing :( Then, I came across >one of my Grandfather's old Petersen shop manuals (1975) and it says, > "Plugs with PLATINUM or other fine wire electrodes and surface gap >plugs having no side electrode should not be used unless specified by the >manufacturer." > Guess what kind of plugs I took out of my car? I now have the O.E. >champions J-13Y and my timing is no longer retarded. The '66-71 used the same >plugs (J-13Y) and '59-'65 used J-14Y; '72 used J-11Y all of 'em are gapped >.035". So I have to agree with Paul, unless the plugs are old or something is >wrong with the engine, plugs don't fail. In fact, according to the same book, >plugs are an excellent indicator of what is > going on inside the combustion chamber. > Anyway, whatever works for ya'-- Do it! > > Keith > 1970 LeBaron