Bob - Bob, it's not even considered to be a flame job. Just a neat talk between frends. Some points to wit re; my responses.
First, the word contaminate is indeed a poor term but I didn't know of a simple word to use other than that. Mineral based oils have parafenes(sp), waxes and other trace stuff that decompose on engine firing resulting in carbon base'd contaminates. So in that respect they do add to the septic tank. Synthetics don't have that problem. I.E. - less in the formulation, the less undesirable stuff comes out. Don't forget we are talking about mixing gas and
oil together with water vapor and emissions for the whole picture. The point to wit is sometimes some of us use what we know about mineral based oils to our advantage.
Next - My lawn mower has a sticker on it plain as day that says- "Use non-detergent
oil only". It's a Briggs engine.
I am big on synthetics, very big- But in all of my readings and experiences no one has shown me anything that proves
synthetic use is better for long-givity over mineral based oils, when used as a manufacturer suggests. We can talk back and forth on this a while but by in large we are in agreement on the big stuff. As for the zink additition thing it came out prior to my responses, but I was using it and Moly as examples of additives that go into the formulations, and as such mean to show the complexity of the subject.
I think the synthitics crowd is just as likely to over generalize their cause/useage as the mineral based crowd is likely to over generalize to. NEXT!
cobrashock