714 South 4th St. Hamilton, Montana 59840
R.M. Owen must have wanted to build a long-life, substantial home lighting plant for people who could not access public power sources.
His idea was to use a rotary valve in the engine. The valve itself was a cone-shaped plug with two recesses in the near vertical side of the plug. As the plug turned, the recesses provided a passage from the intake to the cylinder; then as it rotated further, it provided a passage from the cylinder to the exhaust port. Since the valve had two recesses diametrically opposite from each other, it was only necessary for the plug to rotate 180 degrees for the four cycles or 720 degrees of crank shaft rotation. This is a ratio of 4 to 1 crankshaft to valve rotation, different than any common four cycle engine.
This tapered plug caused other design problems. If the tapered plug was inserted into the receptacle with even a slight force it would bind or seize similar to the action of the Morse tape on a drill shank. To overcome this, the valve was driven by a spring loaded ramp. The ramp was in the form of a triple entry thread, and if the plug had a tendency to drag or bind, it would climb the ramp lifting the plug to relieve the drag.
The spring loaded ramp solved the binding problem if the direction was always in the forward direction, but if for some reason the direction was reversed, due to backfire or reversed cranking, the ramp would force the plug down and it would bind. To prevent this, a one way clutch was inserted in the drive shaft to the valve to prevent any backward rotation. If backward rotation did occur the dog type clutch would release. Then on forward motion the dogs would drop into their indents and operation would continue normally.
The unit is of a clean design with no external moving parts. The valve, oil pump, governor and timer contacts are all driven by a vertical shaft which in turn is driven by a helical gear on the main shaft. All moving parts are supplied with oil from the crank case by a rotary pump; even the outboard bearing on the generator is pressure lubricated.
The control panel originally provided automatic starting and stopping, using watt-meter type relays to keep the batteries fully charged.
The nameplate lists the serial number as 101 and a generator rating of 85 amperes at 32 volts. Using an efficiency of 80% this translates to approximately 4.55 HP from the engine. Using the tabulation in the March issue of GEM, a 3 x 4 inch bore and stroke engine would develop 4.56 HP at 1800 RPM, a very common speed for such a generator.
Although the name of R. M. Owen appears in the index of Wendel's Gasoline Engine book there is no other information listed. I acquired the engine generator set from a friend who did not have any of the history of the set. Any additional information would be very welcome. Enjoy the photos of the engine and its parts.