Rotella 15w40

greymouser7 said
a point of observation (not intending to contradict yellowrose, or anyone)
Is that there have been knuckle heads that have replaced their oil with automatic transmission fluid and driven for weeks or months...”I never had any problems running X, Y, Z motor oil whether for diesel, or nonsynthetic, or whatever oil doesn’t represent but a sliver of real estate.

those previous mentioned knuckle heads with automatic transmission fluid in their didn’t have any initial problems either.

what we all understand is the rate of wear regarding particular oil, rings, machine-finishes is the REAL question

and without SCIENTIFIC data, personal experience,

unless you basically are a race team or can measure cylinder bore wear with a measurable method of oil use

-is just a shot in the dark, it isn’t significant evidence.

Yep. You can be pretty abusive to the engine with oil and it will still live.

It is very difficult to see the difference in oils without accurate dyno testing and that’s dang expensive.

One thing I found is that the better oils significantly increased my valve spring life. By a pretty wide margin. At one point at 75 runs I had to shim the springs and at 125 runs they were used up. With a quality oil, I could go nearly all year (sometimes over 170 runs) before they needed a shim and then I could get another 75-80 passes out of them, as long as I played nice and shifted at 8500. If I stretched it out to 8800 or a bit more trying to make a hero run if I had Disney land conditions it would cut spring life by about 35%. And that is costly when youare dirt poor like me.