This reminds me of when I worked in an aircraft engine overhaul shop and had an oil burning engine (past the rings, chromed cylinders with cast iron rings) come in for repair. The engine was at the recommended time between overhaul, so the shop owner decided to see if the benefits of putting Bon Ami in the oil to seat the rings, as the street wisdom suggested, would really work. We ran the engine with the additive and could note no external benefits (fully instrumented aircraft, cht, egt, oil temp, oil pressure, rpm). Upon teardown, the results: were gummed up rings, junk in all of the oil passages, hydraulic lifters, and no effect on the cylinder walls (still glazed from an improper break-in procedure many hours ago). Nothing positive, all negative for this test,