I've got a great PDF on oil that covers just about anything you would want to know. Everything from bypass filters to technical specs to brand comparison charts (wear rating, ect. ) It was last updated in 2003, so it is a few years old. Unfortunately, the online link no longer works and I can't upload it because of it's size, 3 MB, 177 pages. So, if anyone is interested shoot me a pm and I will get it to you. I'm not advertising anything, just trying to spread some excellent information, especially those new to oil. 
