Coolspring Spotlight: 25 HP Evans Engine

This circa 1920 25 HP Evans engine features power operated intake and exhaust valves.

| December/January 2015

  • 1920 25 HP Evans engine
    The circa-1920 25 HP Evans engine at the Coolspring Power Museum.
    Photo courtesy Gas Engine Magazine staff
  • 25 HP Evans intake and exhaust valves
    The Evans engine features power operated intake and exhaust valves.
    Photo courtesy Gas Engine Magazine staff
  • Masseth and Black vacuum pump
    The Masseth and Black vacuum pump being driven by the Evans.
    Photo courtesy Gas Engine Magazine staff

  • 1920 25 HP Evans engine
  • 25 HP Evans intake and exhaust valves
  • Masseth and Black vacuum pump

Manufacturer: Evans Mfg. Co., Butler, Pa.
Year: 1920
Serial No.: NA
HP: 25
Bore: 11-1/2-inch
Stroke: 16-inch
Ignition: Hot tube
Governing: Throttle
Owner: Paul Harvey
Museum location: Power Tech Annex

This display consists of a 25 HP Evans gas engine driving a Masseth and Black vacuum pump, officially known as a gas pump power. Located in Butler, Pennsylvania, Evans was a manufacturer of oil field equipment and made 4-cycle gas engines that were noted for their exceptionally smooth running and long life.

The engine is a typical 4-cycle gas engine that Evans made. The unique feature of the engine is that it has both the intake and exhaust valves power operated. “From available literature, it looks like this was designated as one of their commercial engines and probably one of the larger engines that Evans made,” Coolspring’s Clark Colby says.

The vacuum pump that the Evans powers by flat belt is a Masseth and Black, also built in Butler, Pennsylvania. Masseth and Black made an extensive line of oil field equipment but did not make their own gas engine. According to advertisements, the pump served a couple of different purposes. The main one was to draw a vacuum on nearly exhausted gas and oil wells to increase production in the cases where the rock pressure had gone pretty much to zero. The other advertised use was for mild pressurization of a gas line to distribute gas in small towns.



Both the engine and the vacuum pump spent their working lives in Fairview, Pennsylvania, but on separate applications. The engine worked in a pressure plant where it drove a compressor to re-pressurize natural gas to the oil wells to increase oil production. The vacuum pump served within a mile and a half of the location where the Evans spent its working life and was used to draw a vacuum on some oil wells to provide a little bit of secondary recovery. Today, the units are appropriately belted together and provide a unique display of oil field technology.

Want to learn more about this engine and 38 others? Check out Coolspring: Discovering America’s Finest Antique Engine Museum and see them run on the Coolspring Museum DVD.



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