What makes Swepco 306 15w40 different from any other diesel oils?
Harley’s SYN3 didn’t reduce the Zn or P, just supplemented it with the added boron. Similarly, Swepco’s 306 has high levels of boron in addition to high levels of Zn and P, but in a non-synthetic product using highly refined paraffinic base stock similar to Brad Penn. Since we are discussing aircooled engines specifically, the highest levels of boron we had previously found, which is matched by the Swepco 306 15w40, was in Harley Davidsons SYN3 motor oil. Boron, which is a supplemental zinc-free anti-wear additive, was present in these oils at levels six to ten times that of what is present in any reformulated SM or CJ-4 motor oil. It has been shown that boron works synergistically with the ZDDP and it’s performance is tied to levels of the ZDDP. Additionally, Swepco is among the minority of lubricant manufacturers choosing to manufacture and market the newer CJ-4 rated oils along since previous CI-4 and earlier lubricants to address the requirements of older engines rather than forcin
