Above: right side view
Below: left side view
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ENGINE NO. TWO DATA
Cylinders: 2
Type: 45º V-Twin, DOHC
Bore: 1.062”
Stroke: 1.125”
Displacement: .995 cu in/cyl x 2 + 1.993
cu in
Compression Ratio: 7.9:1
Ignition: Glow plug
Cooling: Air
Fuel: 15% nitromethane/methanol mix
Max. RPM: 11,000
Est: Horsepower: 2.0
BUILDER'S NOTES
Background -- This engine
was a somewhat similar version of the first DOHC Harley-Davidson
motorcycle engine (the one prior to the current Porsche-designed
model). It doesn't follow the Harley pattern exactly but at
least looks somewhat similar.
Construction -- The
valve train was timing gears and timing belt to the cams.
It was a somewhat difficult engine to make and the results
were OK but not stupendous. It could use more development.
Of course you can say that about almost any one-off engine.
The second one you would make would have some improvements.
This engine crankcase was made in two halves which I made in
pieces which I were welded in place. I then finished them in
the mill. The crankshaft was steel and a bear to make as it
was in three pieces per the Harley system. This consists of
crank throws with tapers to lock into the main journals. I'm
not sure that Harley did this in this engine as I never got
to see the inside of one, but it requires some very close tolerances.
Operation -- This twin ran
OK but used a single model carburetor which was not too flexible.
If I do any more develpment
on this engine I would design and install a couple of slide
valve carbs.
On Castings...
I got interested in making
my own foundry and casting some of the parts for my engines.
It sounded good but I soon realized tha if I were to only make
one unit I might as well go directly to the billet and hog the
parts out from scratch. After all, with castings you have to
make patterns, get them to cast properly, and still machine them.
I finally decided to eliminate the casting process, since I only
make one of each engine. The foundry worked well but was not
much of a solution to making small engines, one at a time. I
spent time later in making fixtures which gave me two more axes
in my mill. I call it MDC or "manual digital control".
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Detail of carburetor
and camshaft drivetrain.
ENGINE DETAIL PAGE LINKS
(click on buttons)
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