</font><font color="blue" class="small">( They are not that great. )</font> The oil doesnt have to be that great. The oil only has to protect the moving parts adequately enough to prevent premature failure. What you are talking about is how much "margin" in those numbers do want to have? Marketing is at work in this particular issue.
Bottom line is this: "Is your engine adequately protected from severe machine wear or not? How much protection do you need?"
If longer drain intervals is important to you, then get the lube with the most additives, as this poster described. However, if the original poster describes that Delvac is a very good product, then YES this Delvac will provide adequate protection for the user.
As a basic approach, a user changes the oil when the additives are depleted. You can use oil analysis for this determination or use time based recommendations from the mfg or oil supplier (since the mfg has no idea the operating conditions for you, so he assumes worst case, i.e. severe operating conditions).
Overall, Junkman is probably accurate in this case. As a tractor owner you really dont need to crunch all these numbers and evalute the merits of each oil. What is the most important thing for us is that the oil is changed periodically BEFORE any significant damage occurs to the engine. Synthetics do a better job of it. No question about it. I seriously doubt any of us are going to use our tractors enough to ever see an overhaul required....i.e. 4000-8000 hrs.
I use Delvac 1 in my new Kubota
L3130 and change oil based on the mfg recommended 100 hr intervals.
just my $0.02 worth.
dwight
OBTW, maybe my dad was right.
"Buy the cheapest gasoline you can find and buy the most expensive lubricants you can find".
