This is completely unrelated to an modern automotive synthetic oil. First off, the problem was with the lead in the avgas which obviously isn't an issue with automobiles. And second it was related to the fact that being an ashless oil there wasn't much in the oil in terms of any kind of additives to scavenge the lead. PAO is a poor lead scavenger by itself. So only if you had pretty significant blowby in the engine was this a problem.
An automotive synthetic in a automobile engine never was and never will be a problem like that which plagued AV-1, even if you are running leaded gas.
Originally Posted By: stickybuns
There was a time in the 1990's when Mobil synthetic gas engine aviation oil was destroying some engines. Mobil pulled it from the market and kept lawyers in Mercedes for quite some time. See
http://www.avweb.com/news/news/182891-1.html?redirected=1
Some excerpts that sum it up if you don't want to read everything:
"Cylinder removal consistently revealed abnormal top-end wear, stuck and sludge-fouled oil control rings, and a thick coating of black sludge on the underside of pistons and on visible portions of the crankcase interior. "
"But it's those same smooth, ultra-slippery molecules that give synthetic oil its Achilles' heel: the inability to hold lead salts and other contaminants in suspension. The synthetic oil molecules are simply too [censored] slippery to hang onto such contaminants, so they settle out of solution and form sludge deposits, particularly in areas of oil stagnation such as prop hubs, oil pans, and the inside of pistons."