Oil pressurization is not what makes a hydrodynamic bearing, such as main crankshaft or connecting rob bearings work. What makes the bearing work is the rotation of the shaft; the best analogy I ever heard is that the shaft 'water skiis' on the oil. As the shaft rotates, it shears its way through a layer of oil, and the shear forces all balance and are evenly distributed around the shaft. But when you push sideways on the shaft and move it from the center of the bearing housing, the shear forces where the shaft gets closer to the outer housing skyrocket; this is what supports a crankshaft in a running engine.
A lot of people seem to think that something like a crankshaft or connecting rod bearing touches the shaft only occasionally, only on start- up, etc., etc. but in fact, the shaft virtually never touches the bearing shells. Bearings are made out of lead, aluminum and copper generally and you can easily scrape the bearing material out of the bearing shell with a pocket knife. Such a bearing would not last even a few revolutions of the main shaft if it were not coated with oil.
Pressurizing galleys to feed main and con rod bearings merely makes sure the gap is full of oil and provides enough oil flow through the bearings to cool them. Note that small, one cylinder engines have no pressurized oiling systems and yet function very well with hydrodynamic bearings. So getting oil to each bearing, under pressure, is important but not crucial nor is it particularly time critical regarding the difference between a few seconds or perhaps twice that amount of time.
Brian
There probably is oil the bearings but I THINK you need oil pressure to provide a lubicating layer between the moving parts. Not an expert here
