Pretty sure this is a Ryan ST-A sports aircraft, equipped with a Menasco D4 Super Pirate engine.

There were many European companies making such air-cooled inverted inline aero engines in the 1920s and '30s, but the most famous and numerous were the de Havilland Gypsy and the Blackburn Cirrus lines. The American Cirrus Engine company making their British engine in Detroit was bought by Menasco in 1935 and some ideas incorporated into their engines like this D4. Menasco from Los Angeles was the unique completely American manufacturer of such engine types, having made their first in 1929.

The Ryan ST-A aircraft is famous all by itself and is quite pretty:

https://www.pilotweb.aero/aircraft/flight-tests/flight-test-ryan-st-a-th...

The plane and the engine in the photo look a tad worse for wear externally, probably from all the students prodding it about for years. Kind of unique stuff to practice engine/aircraft maintenance on!

Someone put the engine in upside-down!

If I were a mechanic and wore white while working around and underneath an engine, I'd be covered in oil and grease in no time! In fact, mine would get dirty as soon as I walked out the front door! The only thing that wouldn't look oily or greasy would be my hair.

When I was in trade school, most of the engines and transmissions had been torn apart and reassembled so many times the fasteners had shop wear.
My guess is this shop plane never left the hangar.