Originally Posted By: Shannow
Originally Posted By: CT8
The most important thing we are missing here [a BITOG reader failure] is how much time does it take for the oil to travel from the sump to the oil pump? Any one ever look at the SAE oil viscosity temp/viscosity charts?
Here's a test engine running oils with different "W" ratings, including SAE30 with no "W" rating at various temperatures. It includes the time to get oil flowing to the rocker arms (RAOT, so same as the Esso video), and time to full oil pressures (FOPT).
clearly, the SAE30 "flows" as well at 20F as the 5W20 "flows" at 12F, and the 10W30 does at 9F...in this test engine.
So the "W" rating and the operating temperature are important.
Take any of the three oils at 30F, and regardless, none of them are going to "beat" the SAE 30 time of 3 and 6 seconds, as that's the mechanical filling rate of this engine.
Above freezing, whether the owner chose 0W, 5W, 10W, 15W, or straight 30, nothing is going to "flow to the top end" any faster
So out here in the SF Bay Area where we hardly ever see temps in the 30's F leave alone 20's - we should just run SAE30 and be done with it. We have no real need to run a multi-anything
And, all kidding aside, that's why my old boss on the ranch ran straight 30's in all the 2-stroke diesels. They tear up oil due to open port configuration. I was always on him about why not newer oils with this and that magic properties. He'd just smile and ask how long I needed the motor to run...
Having been around a bit longer now, I get it. Find the best oil for the job at hand.
Your conditions may be at the edge of what the engineers considered normal for that engine. IF that's the case you need to make allowances. Look at the world spec for that engine (to get CAFE out of the equation) and pick the right oil for the job