Think of it this way, lead babbit bearings are probably the softest thing to use for a bearing, but with an oil film under pressure, the crank and bearings never actually make contact. The force of combustion is supported on that oil film. Most of bearing wear occurs on start-up, before oil pressure comes up. Coolant thins out that oil film and allows contact between the crank and rods and the bearing inserts. The reason lead babbit is used is it will allow hard particles to imbed in the lead and not score the crank.

Some race cars use an oil pressure accumulator, a tank of pressurized oil held closed when the engine is shut down, then allowed to fill the engine with pressurized oil the next time it's cranked for start. It's simply an inverted cylinder with a valve in the bottom that's connected to the ignition circuit. The oil fills the cylinder compressing the air in the top until it reaches operating pressure. I've seen these on nitro-burning dragsters.