.........Searching the forums there seems to be some debate on the type (synthetic vs. non) of oil you should run. The only thing that seems consistent is people adding ZDDP to their oil of choice. I'm curious as to what weight people are running and if one brand as shown better results over another with these engines. Are these engines prone to sheering oil?...............................
Again we have the "what oil is best" thread and every time it is the same old answers, "this is what I use and it is the best", and pages of posts with no substance of what is real and valid information, and somewhat lacking in common sense?
Just because the average GN owners want the "best" for his baby, the more expensive is not necessarily the best in most cases.
The last thing I want to see or hear is "info and data" quoted from the manufacturer, or from the advertising department, and their product is automatically the "best", but best for what?
They have no clue that our engines are based upon a 50 year old design, and it is a performance application with forced induction.
Forced induction, or turbo engines, will put much more contaminates into the crankcase, and hence into the oil, than your almost new daily driver, and the operating envelope is much different.
The point here is any oil will be contaminated and needs changed before the additives are used up. A race car will need a change about every 20 passes, and a modified GN on the street should have the oil changed between 1000 and 2000 miles depending on how hard it is driven.
One comment that messes with my head is using Diesel oil in a high performance engine?
My Dodge diesel never has been over 3000 RPM, and usually is pulling well below that number. Traditionally diesel oil is formulated with less anti-foaming additives, and much more detergent to clean the cylinder walls, just what you do not want in a performance build.
The answer I get from guys using synthetic oils is that it will last longer. Really, are you going to leave contaminated oil in your engine for 15,000 miles, or even 7000 like some claim? Hell no you won't. So spend your $$$ on more often oil changes, because it will NOT protect your engine any better than regular oil regardless of the brand.
Over the years we have built, installed and shipped over 600 turbo Buick engines, and we inform the customer if synthetic oil is used, there will be no warranty whether it is a flat tappet or roller cam.
One property we have found with regular vs. synthetic oil is that the synthetic oil does not adhere to friction surfaces, or any internal surfaces, like regular oil. Synthetic oil will drain off cylinder wall and bearing surfaces in a day or 2, regular oil never will.
I know there are many different opinions on oil choices, like other items, but basing your choice on experience, operating use and factual information rather than emotion or advertising, would serve your purpose better.