Above: right side view
Below: left side view
ENGINE NO. EIGHT DATA
Type: Hit & Miss Vertical
Displacement: 0.996 cu in
Compression Ratio: 7:1
Ignition: Coil/Spark plug (later glow
Cooling: Automotive coolant
Fuel: 15% nitromethane/methanol
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.
ENGINE DETAIL PAGE LINKS
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