Bad oil??

I've generally used Valvoline products since the mid 1980's. I did run Castrol in a few motorcycles. I still like the VR1 Racing product, though I realize the zinc has been reduced so I'm reading with an open mind, may move to something else. I certainly like 20W50 for boats, 10 weight is just too thin for this use in my opinion.

But ... I've never had an engine fail from "bad oil". Lots of boats, tractors, cars, and trucks have run a variety of oil, nothing has ever prematurely worn or failed that I know of because of oil brand.

It makes sense to run the higher zinc oils in boats that rev high, accelerate hard. But, we all know that lots of boat owners put whatever 10W30 is cheapest in their engines. If they change it on schedule, it's likely their boat will last just as long as mine!

Brian, that's not really an oil related failure, but rather a gasket failure.   

I've said in a few threads that I'm a Valvoline user for the most part - but I do use Amsoil in my '97 diesel Suburban. I'm in the middle of a long term oil test with an Amsoil dealer from PA. I run Amsoil Synthetic Diesel & Marine 15W40. My used oil analysis sheets show around 1350 ppm zinc.

I'm sure it would make incredibly good boat oil, I've thought about using it or another Amsoil product. I'll have to be convinced that the VR1 Racing oil is not up to task before I make the switch, it's just so easy to pick it up at Autozone when I need it.