Quote Originally Posted by kitz
So the oil pump delivers this flow to the bearings (and all other friction components). The amount of flow the positive displacement gear pump supplies and the restrictions in the supply circuit including the bearings etc determine the pressure the that the system operates at up to the setting of any internal pressure regulating devices that may be present in the system.

Remember the first rule of fluid flow. Flow creates pressure, not vice versa ............. Uh maybe I got off track a little ........
Kitz
As to your comments in the first paragraph I'm quoting, I would only add oil viscosity to your list of factors contributing to pressure readings. I know YOU understand that concept as you referred to it in the previous paragraph (not quoted). Virtually every single inquiry I can recall about oil pressure readings fails to mention two factors; oil viscosity, and observed pressure reading at X rpm. Sometimes it will be prompted out of the questioner, most often not. Well intentioned responders will say something like "Yeah, I get X pounds of pressure at idle"...........totally meaningless as a comparator since it's very incomplete information.

As for the second paragraph; No, not off track at all from the original intent of the thread. However, as someone who has been trying to teach the concept that flow is more important to lubrication than the pressure reading in of itself, I will warn that you're engaging in frustrating endeavor. The concept of oil pressure being the source of lubrication is so deeply ingrained that there is often no room for consideration of it's source or it's significance. In my opening post here I mentioned that pressure, and more importantly a change in pressure when all other factors (viscosity, temperature, engine speed, etc.) is most useful as a diagnositic tool rather than a guarantor of lubrication occuring. The whole point of the story in the link I attached was that the guy destroyed two new engines because he believed that a relatively high pressure reading on his gauge meant he was getting oil to the bearings. He was wrong, and in it's original text he went into great detail as to how he caused his own problems. As you can see, folks have chosen to argue the point even in the face of empirical evidence contrary to popular misconception. When you (me, anybody) appears to be attacking the sacred cow of oil pressure, in the interest of putting it in perspective, all open mindedness seems to flee.