I am going to swap out my spark plugs after work today and I have a few questions. I am going to be going with NGK copper's and they usually come with a gap of .030+ and I want to be at a .028 gap. What do you guys do to shorten the gap? I've been told by some to tap the "prong" down on a hard surface to close the gap but have also been told that this is bad. What is the correct procedue?
Now after closing the gap is there a special way or tool to use to widen the gap to .028? I've been told that the wire gauge is the best to use to check the gap because the coin piece leaves a slight angle. Is this correct? Thanks for your help.