Upper cylinder lubricant
Wondering if upper cylinder lubricant really does any good - or harm. I've used it (Marvel Mystery Oil, Lucas) for years, primarily because it seems logical to me that a touch of lubricant in the combustion chamber is a good thing. I've not had any obvious problems from its use, and feel like it does some good - but I don't really have anything to base that good feeling on. I'd like to hear from some of you knowledgable guys on the forum.