| Howell
V-Twin 4-Cycle Gas Engine
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This is a V-Twin engine
that is machined entirely from bar stock. It has no
prototype as it is entirely my own design. Being a
single crank pin 90 degree engine, it is extremely
smooth and vibration free. V type engines other than
90 degree can not be balanced except with special
balancer shafts, etc. that you wouldn't want! Witness
the vibrating 45 degree motorcycle engines...... The
engine is a long stroke, moderate speed design which
provides plenty of torque. A robust cooling system
allows the engine to run indefinitely with a load and
never overheat.
Cylinders are of cast iron. Crankshaft is steel. Most
of the rest of the engine is of aluminum alloy. Knife
and fork aluminum alloy connecting rod ends operate on
a single hardened crank pin. This configuration
produces an interesting exhaust sound! An internal oil
pump ensures that lots of oil gets to all the internal
moving parts. The crankcase holds two ounces of oil.
The engine is equipped with ball bearings on all
rotating shafts. A sheet metal shroud on each
cylinder/head directs cooling air from a pair of belt
driven fans. Dual 2-Jet Throttles have oiled foam air
cleaners. The valve rocker arms have ball bearing
rollers on the valve stem end and clevises with lock
nuts on the push rods for valve clearance adjustment
on the other end of the rocker arms. The valve train
is designed so that there is no side thrust on the
tappets or the rocker arms which causes undue wear on
other engines.
The engine operates without any oil getting on the
outside due to "O" ring seals at all joints
and an efficient crankcase check valve ventilation
system which maintains negative crankcase air
pressure.
The ignition system is twin Hall sensor and twin TIM-6
electronic ignition modules and two model engine coils
operating on 6 volts. Each cylinder is treated as a separate
engine and this precludes the need for a
distributor. The spark advance/retard is easily
adjusted during operation. Spark plugs are the low
cost 10mm NGK CM-6.
This is NOT a beginners project, but anyone who is
particular about his work, has built a few other
successful internal combustion engines and has a 7
inch or larger lathe and a milling machine with a 6
inch rotary table should not have any problems
building this engine.
Besides just being a nice engine to have and operate,
this engine would be great fun on a bicycle or in a
radio controlled boat, car, tank, etc.! This is a
small "real world" industrial quality engine
capable of doing "long hours" of hard work.
My engine operates all day long at shows driving a
generator and is stopped only long enough for
refueling.
The plans include all
engine features in the photos (except the mounting
rails) including the throttles, cooling fans and air
shrouds, plus an ignition system schematic diagram and
timing gear cutting charts.
The quality CAD generated and laser printed plans set
consists of 41 sheets of drawings and 3 sheets of
construction notes.
Specifications: Flywheel Diameter:
4",
Cylinder Bore: 1",
Piston Stroke: 1-1/4",
Compression Ratio: 5:1,
Displacement: 1.96 C.I. (32cc),
RPM Range: 800 - 4,500,
Height: 6.9",
Width: 8.3",
Length: 5.8" Experience
Level: 5
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"I built the 'Howell' V-Twin' last year. Runs great!!
Fabulous engine!!" - Jim Billings (Fort
Worth, Texas)
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