20 HP Stanley Cylinder

This is a piston valve 20 hp Stanley cylinder machined casting. The design is by Dave Nergaard and he has several for sale. It is designed to be bolted to an existing Stanley engine with the only modification being to reverse the eccentric drives to the valves because of the piston valves. Traditional slide valve Stanleys had a weakness in spalling or galling when the oil injector into the steam line did not work or under high steam pressures and high superheat. It was very difficult to get at the valve face through the steam chest opening to machine the face smooth. Therefore it is much easier to replace the casting with a piston valve design that is both 10 % more efficient and will never spall because there is no side loading of the valve. A further improvement of this design would have shorter steam passages between the valve and the cylinder heads.

New Cylinder 20 HP Stanley This is a piston valve 20 hp Stanley cylinder machined casting. The design is by Dave Nergaard and he has several for sale. It is designed to be bolted to an existing Stanley engine with the only modification being to reverse the eccentric drives to the valves because of the piston valves. Traditional slide valve Stanleys had a weakness in spalling or galling when the oil injector into the steam line did not work or under high steam pressures and high superheat. It was very difficult to get at the valve face through the steam chest opening to machine the face smooth. Therefore it is much easier to replace the casting with a piston valve design that is both 10 % more efficient and will never spall because there is no side loading of the valve. A further improvement of this design would have shorter steam passages between the valve and the cylinder heads.


		Dave Nergaard and Tom Kimmel


(Note: Click on a picture for a larger view, then enlarge it further through your browser.)


For More Information or availability for purchase, please email: nergaard@verizon.netLittleton, Massachusetts - Both machined and unmachined blocks available.



20hp Stanley piston blocks



Stanley 20 hp "D" Valve cross section

Stanley Piston Valve Block