This is the engine in a 1911 Buick Model 33

This is the engine in a 1911 Buick Model 33: a 165-cubic-inch (2.7-liter) four-cylinder valve-in-head engine (OHV), rated at 22.5 horsepower.

You can also see the magneto and water pump...the water pump almost looks like a modern turbocharger. Directly below the spark plugs are the priming cups. When starting a cold engine, these cups are filled with gasoline and then their valves opened, allowing fuel to flow directly into the cylinders.  Makes for an easy and quick start which is strictly by hand crank; the electric starter had not yet made its way into production automobiles.

Also visible are two copper lines running to sight glass on the dashboard, allowing the driver to visually confirm that oil was circulating through the lubrication system.

The brass pipes carry hot coolant/water from the engine to the top of the radiator via the water pump. As the water flows downward through the radiator, heat is dissipated into the surrounding air. The cooled water then exits from the bottom of the radiator and returns to the water pump, where the circulation cycle begins again.