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.
