Quote:
I believe the detergents and dispersants in modern oils will attack the poured-lead bearings in antique engines.
Well, consider this.
Most SA ND oils are simply high sulfur content, minimally refined Group I oils with a small amount (3 ppm) of foam-inhibitor. During combustion, these elemental molecules mix with moisture to form sulfuric and nitric acids.
There are no dispersants, no detergents, no Anti-wear, no metal inhibitors, no VII's, no rust inhibitors, no added anti-oxidants.
In my view, SA ND oils are only good for coating rakes, plows, shovels, etc before storing them.
So how did these ancient machines survive?
They had large clearances (loosey-goosey), low compression ratios, large bearing areas, oversized components for the moderate loads, and were made of only cast iron and steel alloy components, and Lubricants had to be changed at very short intervals.