Tracking Down Historical Combustion Engines in the USA

A Special MWM Moment of Thomas Adam

In 2015, Thomas Adam set out on a research expedition through the USA, searching for known and unknown combustion engines of historical interest. To find such rare exhibits, he especially focused on the engine collections in various well-known technology museums.

One of these was the Coolspring Power Museum (CPM) in Coolspring, Pennsylvania, which had been established in 1985. The place turned out to be a veritable engine Eldorado: The museum boasted an extensive collection of engines from the USA and other countries.

Hidden behind a huge horizontal engine, Thomas Adam was surprised to find a small, somewhat dilapidated engine with the type plate “Benz & Cie.”. The great question: “How did this engine come to the USA, and what was its purpose?” The answer was readily available. He was also pleased to learn that the museum staff were planning to restore the engine.

The number 21542 that appears on the company nameplate is a Benz factory number. The engine on display is a HoRo RI-24 high-pressure crude-oil engine manufactured by the Benz factory in Mannheim Neckarstadt. The first HoRo engines equipped with Prosper L’Orange’s prechamber system were delivered starting on September 4, 1920. Accordingly, this Benz & Cie. engine is one of the first new prechamber diesel engines delivered back in the time—a valuable find!