How the Engine Lubrication System Works

Here's how the engine oil works to lubricate the moving parts in your engine.
Engine oil begins and ends its journey in the oil sump, at the bottom of the car's engine. An oil pump, driven by the crankshaft, sucks oil up through the pickup tube and pushes it through tiny machined galleries in the engine block to lubricate key components.
Oil pressure is created when oil flow is let through a tiny hole. The hole acts like a restriction, as the oil is let through at a high velocity, sufficiently coating and lubricating essential parts.
Oil then flows from the pump to the filter. The filter consists of an anti-drain back valve and a bypass valve. An OEM Toyota filter is taken apart and a paper filter is discovered to be the filter material.
Further down the line, the oil flows to the crank bearings, and up through the connecting rods to shoot oil at the piston walls and connecting rod bushings. The oil control ring on the piston are what's responsible for scraping excess oil off the cylinder walls so it doesn't get burned during combustion above the piston.
An oil galley feeds the head of the engine up near the top. It first leads off to lubricate the camshaft bearings (through the hollow camshaft), before splitting off into the variable valve timing solenoid and into the VVT-i gear.
A small channel leads off the head to pressurize the timing chain tensioner on the timing cover. A small squirt of oil also lubricates the timing chain itself.
Any remaining oil in the head, block, crank case or timing cover is left to drain down into the oil sump, where the oil is cycled back around into the lubrication system all over again.
The engine demonstrated in this video was from a 2001 Toyota Corolla with the 1ZZ-FE VVT-i engine.