Above: right side view
Below: left side view



Cylinders: 1
Type: Hit & Miss Vertical
Bore: 1.062”
Stroke: 1.125
Displacement: 0.996 cu in
Compression Ratio: 7:1
Ignition: Coil/Spark plug (later glow plug)
Cooling: Automotive coolant
Fuel: 15% nitromethane/methanol mix
Max. RPM: 5,300
Est: Horsepower: 0.75


Background -- Since all my previous engines had been air-cooled, it seemed like a good time to investigate a liquid-cooled unit. This single also included a governor which was operated by a horizontal flyball unit that blocked the intake to control the engine's speed. The open crankcase design allowed curious observers to see how an engine like this operates.

Construction -- The crankcase was held to the base with four brass posts, allowing for a view of the crank, connecting rod and piston bottom. An overhead camshaft carries the exhaust cam and governor. A two-to-one drive open belt was used for cam operation. I made a small vane-type pump to circulate the coolant in the space between the cylinder liner and the outer sleeve. This pump was driven by an o-ring belt off the rear of the crankshaft. A small variable venturi carburetor was used in an atmospheric intake scheme similar to what I used in engine number 3. The blue painted gear you see in the picture is merely a flywheel: it has no use other that that.

Operation -- The engine started readily and ran well but the governor was very abrupt and the engine spit fuel through the carburetor while governing. Very uncouth, that guv'nor. I ultimately decided that governing through the intake valve was not the best way to go and modified the governor to block the exhaust valve instead. This seemed to be more effective and did not waste fuel, make a mess or create a fire hazard. The flyball governor worked very quickly, popping in and out continually. After some experimenting it became obvious that the engine was too high speed a unit to use a governor effectively. Possibly it could work if it had spark ignition but I didn't think it was worth the effort to change. Finally the governor was removed and the engine ran quite well, although the liquid coolant was pretty messy to use. Live and learn.





Detail of open crankcase.

(click on buttons)



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