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"Nicholas Bourne" <nbourne@optusnet.com.au> wrote in message
news:457958b7@dnews.tpgi.com.au...[color=blue]
>[/color]
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>> No self-respecting engineer would design an engine with a firing order of
>> 1-2-3-4 because the power pulses would be too uneven.[/color]
>
> I have a commodore with a buick based V6 in it that has a 6-1-2-3-4-5
> firing order, i'm sure somewhere in the the world is a 1-2-3-4 firing
> order.
>[/color]

The OP has an in-line 4 cylinder engine with cylinder numbers, from front to
back, 1,2,3,4, and the firing order is definitely NOT 1,2,3,4 for his
engine. IMO, telling him that it could be 1,2,3,4 because it may be that
somewhere in the world is not useful advice and is likely to reinforce his
notion that 1,2,3,4 is the correct firing order when in fact it is
definitely wrong.

In the case of an engine with 2 banks like a V or horizontally opposed
configuration, there is more than 1 way to number cylinders. For example on
a V6 engine, one configuration is to have cylinders 1,2, and 3 on one bank
and 4, 5, and 6 on the opposite bank; and another configuration is to have
1, 3, and 5 on one bank and 2, 4, and 6 on the opposite bank. Obviously,
cylinder number designation is a big factor in determining firing order.

Engineers determine firing order by trying to smooth out, or balance the
power strokes with the other 3 strokes of a 4 cycle engine. If the firing
sequence had adjacent cylinders on the same bank firing, the engine would be
unbalanced. In the case of the Buick engine you cited, note that the firing
order sequence is even-odd numbered cylinders, suggesting that the cylinder
numbering sequence is odd on one bank and even on the opposite bank. The
firing sequence does not have adjacent cylinders on the same bank firing.
--

Ray O
(correct punctuation to reply)