All these Engine Of The Day honors, and no Russian iron? And yesterday was May Day, comrades? We're going to remedy that oversight right now!
You can't contemplate Soviet machinery without the Red Army Choir performing The Hymn Of The Soviet Union, so crank up the volume! The air-cooled MEMZ 45° V4 was the powerplant used in the beloved Zaporozhets, a true proletariatmobile built from 1958 through 1994. The MEMZ-968 was the largest and most powerful of the Zaporozhets engines, displacing 1.2 liters and generating 42 horsepower, and it was used from 1972 all the way to the end of the vehicle's run in 1994. It was simple and easy to maintain, very well suited to the climatic extremes of the Soviet Union, and definitely qualifies for workhorse status.
[Wikipedia, MEMZ official history]