It's the Western Enterprise Engine Co. of Los Angeles, CA.

-In 1930, they introduced the L-7, sometimes known as the 7-1. It produced 170 HP and had a displacement of 745 cu in.

-Actually it was a 7-cylinder radial engine that received ATC-45 Type Certificate.

-The Western Enterprise Engine Co. manufactured the L-7-1 radial shown below. It could deliver 170 HP at 2000 rpm.

“Western L-7-1”

-The cylinders have L-type combustion chambers with side valves.

“Western L-7-1 cross-section”

From Appendix 12: The German magazine Flugsport featured a side view drawing of the 170 HP L-7 (or L-7-1). It also included a view of the crankcase and cylinder number 1 at the "12 o'clock" position.

“Western L-7 schematic drawings”