I've run into a problem while changing oil. The allen head filter bolt will not thread completely into the case. The bolt went in fine during the last oil change, and it came out fine this time. I am almost positive that metal debris entered the threads when I removed the filter. By looking, the threads don't appear to be damaged and I may be able to use a tap to remove the debris without damaging the threads. I did a search and found a post on this same subject earlier this month, and I know that a helicoil will fix the threads if the tap doesn't work. I have two questions. First, is this common and is there any way to avoid this happening again? In the previous post Scott F said that Ty Davis recomended fixing this problem with a set screw. Has anyone done this? How do you do it? Second, if I have to use a Helicoil, I know I have to remove the entire side cover. Is there anything special I should know before doing this? I don't like surprises.