No subject

whether in the Northern or Southern hemisphere one engine always runs
better.  Wonder what happens on the equator :-)

Actually, it's kind of funny, but most of the twin engined yachts that have
counter-rotating engines are mostly for "local" use.  Many of the more
serious world cruisers have two engines that rotate the same way.  This cuts
down on the number of spare parts you needs to carry, not only from the
perspective of spare parts, but also so that one engine can be cannibalized
to service the other.  Better to be a little less efficient overall, but
more prepared for the worst case of engine failure.

My guess as to the answer to the question is that engines rotate the same
way, generally, to cut down on the need for extra parts in the industry as a
whole.  It's just easier if starter motors are always wound to crank one
way, and for water pumps to go one way, for A/C and hydraulic pumps to go
one way.  Fan blades in general, those little alternator fans, oil pumps.
I'm sure there are more items.  These are generally off-the-shelf bolt on
parts.

There is close to nothing in an engine itself that is rotation direction
specific -- the cam is all I can think of right now.

Bernard Littau
Woodinville, WA


>     Ok, I got this from my other list subscription and thought maybe this
> list would be a little more enlightened.  I know there are 4k's in South
> Africa and other Southern Hemispherical Countries.  After laughing
> hysterically at the response to the original question, I thought I'd ask
> around to see if there was a better reason.
[snip]
>
> This was asked...Now, why do engines all turn in the same direction?
>
> They don't. Only those in the northern hemisphere do. For reasons
> similar to those that cause vortices to rotate in opposite
> directions in the
> northern and southern hemispheres, engineers found that opposite
> rotational
> direction was more efficient in the southern hemisphere.(Partially
> attributable to the rotational vortices induced in the induction
> mechanisms). Consequently, vehicles intended for southern hemispheric
> combustion require different camshafts, distributor timing gears
> (and marks)
> flipping the rear axle etc..Contra-rotation also explained the rarity of
> automatic transmissions in the southern hemisphere as auto boxes are
> dependent upon fluid pressure to operate clutches and shifts and would
> hence, require a compete re-engineering to function.
>
> One negative result of the export of non southern-optimized,
> contra-rotating
> cars to the southern hemisphere is realized in the early decay of the
> exhaust system. The induced drag in the non optimized induction system
> results in an excess of unburned hydrocarbons (raw fuel) running
> through the
> exhaust system with the expected result. Anyone who has visited
> the south is
> well aware of the increased auto-sourced atmospheric pollution and the
> accompanying din of un-muffled exhaust there.
>
>