Re: Any benefit of Full Synthetic or Conventional/Synthetic Blend Oils?
The problem there was that solid particulates were not suspended and ended up forming sludge, whereas dino will "trap" them and allow the filter to do it's job.
More specifically, the solid particulates were LEAD combustion products that are supposed to be kept in suspension by the (ashless) dispersant additive in AV oil. (Much like the soot dispersants in diesel engine oils of today)
Mobil's AV-1 dispersant failed to do it. Aircraft engines that were operated on MOGAS (Autogas STC) didn't have any problem with AV-1 at all and very few engines that operated on 80 octane had problems (MUCH less lead) . Mobil's syn AD additive actually did the opposite and caused lead "sludging"....They paid dearly for it. There was a huge class action suit.
Automotive synthetic engine (and gear) oils of today are FAR superior. It's just the benefits of using it in a marine engine are not realized because marine engines don't get extended drain intervals. None of the manufacturers allow an extended drain interval when using synthetics In a gear box, synthetics actually produce less heat and gears take less power to operate. (which is why the OEMS deliver gear boxes and transmissions with syn-oil nowadays.....it raises their CAFE ratings)
Synthetic oil will leak through a given size hole a little faster than a non-syn when it's cold because synthetic oils flow better when cold. Get both of them hot and they'll flow through the same hole at about the same rate.....
