Cox Engineering Article
Jack - great comments on that article, which mostly addresses specific matters related to some older, smaller engines. An "auxiliary"? Without looking it up, it's an engine that is a secondary source of propulsion, as an engine on board a sailboat, like my 4.5 hp British Seagull I had on my 1200 pound San Juan 21' (red hull - "Tomato Sloop" - I thought that was clever), but also for some potentially large engines on very large sailing yachts. I wonder if a "get home" engine on a trawler would qualify as an auxiliary? I suspect so. But, the common factor is that these were engines with displacement tasks, whether large or small, more in keeping with Eric's Willard - a classic, well proven displacement trawler. (Aren't they ballasted?) So, to me the Cox Engineering article supported Eric's claims about single weight oils, dino oils, etc., better than the current tech research I had read on oil company web sites, the Tribology site, etc. I'm now more convinced that contributors' thoughts on what is right for their engines makes sense. It doesn't change my mind on what is best for turbo engines like mine with internal temps that rise pretty high with rpm, and per another contributor can "coke" - a scary thought! - or merely cook if oil circulation stops in a very hot engine. That's where the anti-shearing benefits of synthetics comes in - the stats are clear that synthetics have a much higher shearing point and longer life.
So, my concluding point last night that there's ample room to support contributors who mostly seem to be supporting choices that are right for their engines, although API/SAE certifications should be the real guide, making sure that older engines' manual API rating is "covered" by the newer rating. There is at least one oil out there claiming to be effective for engines of pre-2007 manufacturing date, etc. Probably a good choice for some folks.
The real bottom line is that this discussion led me and hopefully others to become more aware of different attributes of different types of oil, and the different needs of various types of engines, ages of engines, and uses of engines that dictate something other than the most advanced oils currently being manufactured. I confess to having been focused on the "best oils" rather than the "best oils for certain engines and applications". (My lawnmower calls for straight 30W, btw, which I provide in dino).
TF provides forums for posing questions, sharing opinions and research, with answers left to each contributor to ponder and adopt for himself/herself. Very Socratic and inductive! Fun!