[Jay S]

We have a variety of different fuels with different injection methods powering engines here. Gas, Diesel and propane with carbs, TBI, MPFI, direct injection, electronic direct injection, and stupid simple fuel mixers. Just my opinion, but I think the diesel oil became popular on the carb’d engines because the oil does not stay very clean very long, and they like the combo of antiwear additives and extra detergents to extend the miles between oil changes to decent intervals. Metal hardness has been creeping down in camshaft components, and need more and more protection, the diesel oil might be the best choice anymore if you need more protection for that stuff. But oil can only take things so far when the metal is junk.

To me there is no question the fuel type and fuel delivery method make a difference on engine life and oil, and best results are usually not with the same oil on everything. The electronic direct injection make a pretty remarkable difference on cylinder wear. It use to be on over the road trucks we would need to do an inframe OH at 700,000 miles, with a combination of a lot of different tech, some OTR engines more than doubled that now. My propane engines run non-detergent oils. The oil always looks new when it is changed, and oil analysis reflects that also.. As good or better than any modern fuel system. On wet fuels, anything below some type of direct injection has an impact on washing cylinders with fuel, and eventually get to the oil.

I have not had much better luck with the “modern machining” than the old school machining. It almost never fails that something in the modern engine fails not long after the old engine.

A few months ago I found a 78 Trans Am for sale with a W72 that had 320,000 miles on the original untouched engine, bought new by the owner. Highest milage I have ever seen on a Pontiac. I wanted to buy it but my wife would kill me. Lol

This fall a friend came across an early 2000s Ford F-150 that had 670,000 miles with the engine untouched, he took a picture of the odometer. He told him Ford should give him a new pickup for driving it that long. Hard to read, but here is photo he sent me, pretty impressive.