The timing gears on the Flathead/Ardun are a good feature. Aluminum on
the cam and steel on the crank. They are helical to reduce or eliminate
noise. For racing they would be even more ideal if they were
straight-cut gears, but would make more noise. The slightest clearance
in the gear mesh would have the gear teeth rattling against each due to
tiny backlash motions in the cam and crank. The beloved Vincent
motorcycle engine is well known for this noise, as are the Harley and
Triumph twins. The helical gears have a small end-thrust which is less
ideal, but probably insignificant in terms of drag loss. Helical gears
make less or no noise because at least two teeth per gear are always in
mesh.
The racing small block chevy would have an ideal setup with the
reverse-rotation cam and two straight-cut gears, but the cam would
always be a non-standard hassle.
Had a dusting of snow yesterday down here in the Dismal Swamp, and a
touch of ice on the roads brought a slew of crack-ups, since folks down
here don't know how to drive on ice. We're lucky with the climate here
in coastal Virginia, the "ocean effect" usually keeps us just warm
enough to dodge snow. Cheers, Ardun Bill
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