This engine started life as a small Sears
compressor I used in my garage for many years, mainly to air up
tires. It picked up a leak in the tank from rust, so I was going to
junk it. Then I thought of making another compressor engine [see
Robert’s other article, “Compressor Engine,” on page 5 of the
February 2004 issue – Editor]. To be different, this time I would
make an inverted engine using the same governor, fuel and ignition
mechanics as the Au-To Air.
Inverted Issues
After building this engine, I can see why inverted engines are
few and far between. On this engine the base and exhaust valve
bracket are both attached to the head. This makes it difficult to
time and make valve adjustments. Also, if the engine sits for any
length of time, oil seeps into the combustion chamber and fouls out
the spark plug.
One thing about fabricating your own engine is the field is wide
open for your own design. The paint – and lots of spit and polish –
can separate a home-built engine from a manufactured engine or a
“look-alike” model.
As you can see, the lion heads and legs on the trucks are very
unusual. I carved the patterns in wood and cast them in aluminum in
my home foundry.
This is a hit-and-miss engine with heavy, 8-inch diameter
flywheels. It has a 2-1/4-inch bore with a 2-inch stroke. The one
end of the crankshaft did not extend through the housing, so I
added 5 inches to that end of the crankshaft. I made the round part
of the base from the cylinder sleeve of a 3 HP International M, and
I got the valves from a small Clinton engine. The flywheels are
brass and were cast by a fellow member of the Mo-Kan Antique Power
Assn. of Kansas City, Mo. Engine speed can be controlled by a
collar and setscrew that can be moved up and down just below the
flyweight governor. The fuel tank is enclosed inside the base.
As manufactured engines are getting more expensive to collect,
and rusty iron harder to find, a compressor engine may be the
perfect alternative to stay busy when cold weather sets in.
Contact engine enthusiast Robert Best at: 3521 NW 60th
Terr., Kansas City, MO 64151; Roduebase@kc.rr.com
