I know everybody is saying longevity isn't proven, but the bare fact that the Lincoln engine Ford tore down with 100,000 miles on it still had visible hone marks in the cylinder walls and didn't show more than the 500 miles on dino oil, that speaks to me. I don't know why others can't see that as a positive.
That spoke to me too Capthead; and, I semi-recall of hearing/reading about that same type of quote - back in the day!
What I don't understand: If that was true back in the 70's, and syn oil improvements have been made since - WHY is there not a plethora of engineering and successful accountings of syn oil usage in all forms of periodicals, on the net, on YouTube, touted by motor manufacturers and on and on and on. Guess what I'm saying is if synthetic oil is such a great improvement over dino oil why is that fact not plastered all over the place?? Is there (are there) some "hidden" down side(s) simply not spoken of (besides initial product expense - which equalizes out once extrapolated alongside other long-term costs that are clamed reduced by using syn oil)?
I'd love to use a new type of oil that increases (maybe doubles/triples) the life of my classic, flat tappet gassers, however, there is just not enough engineered proof and product accountability yet available to make me turn away from high quality dino oil and 4oz ZPPD zinc additive I include at each oil change (can zinc be added to syn oil?). The Lincoln owner in 1970's article and some private boat/land-vehicle users/owners are the accountings I read. Basically - Where's the Beef?? I.e., officially documented and proven blind test studies worked with a myriad of participating engine types under the pressure of myriad different circumstances. I need use-proven laboratory reports before I take the chance with my classic engines. To hear it from users... in their opinion syn oil should rule the world of lubrication. From a post earlier in this thread syn oil only holds 6% of U.S. market with just 30% of that 6% for commercial use. The numbers just don’t add up after 4 + decades of syn oil in existence. Again, Where’s The Beef??