Bob Palmer wrote:
> Steve, et Listers,
>
> The timing order change on the 351W/C/M and 400's, as well as on more
> recent roller cam 5.0L engines is another one of those interesting
> mysteries of Ford engineering. Again, I ask, why did they do that? I have
> even considered putting a 351W cam in my 289 just in case there was some
> kind of advantage. However, there really isn't much difference in these two
> firing orders; one is just the mirror image of the other. Just make #1 = #4
> and #5 = #8, etc., and you see the two firing orders are the same. Harder
> still to believe making this small change could affect the exhaust sound.
>
> Bob
Bob,
Not that I claim to understand why Ford, or Chevvy for that matter, do what they
do. I suppose Chevvy put the spark plugs below the exhaust manifold because of
some advertising tie-in with burn salve manufacturers.
But I do believe that firing 7, then the adjacent cylinder 8 doesn't make for a
balanced sound. I would think you would want some simple harmonic distributions
to allow the rarefaction waves to extract gases from another mate of the 'bunch
of
bananas' manifold. Having two cylinders fire side by side doesn't do this. So
you can't find adjacent firing cylinders (I don't think) in the other cam.
This is worse than those rubix cubes.
1 2 3 4
5 6 7 8
The sum of the squares of the opposite cylinder times the number of times
adjacent
cylinders fire per hundred revolutions, divided by the average piston speed
times
the mach number of the exhaust gas at the valve tip will obviously lead to the
solution.
{9->
Steve (my head hurts)
--
Steve Laifman < Find out what is most >
B9472289 < important in your life >
< and don't let it get away!>
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