V8 Firing Orders
Out of curiosity I have been "collecting" V8 firing orders. So far I
have found 5 unique firing orders for a conventional 90 deg bank angle
cruciform crank V8. For clarity, cylinder numbering is from the front
of the engine to the back, so odds are on one bank, evens on the other.
They,
along with their twins (cylinders numbered back to front), Ford
numbering system equivalent, and a partial list of engines that use them
are:
Original Twin Ford
12784563 15436872 15486372 Ford Flathead Lincoln Flathead Ford Y-block Lincoln OHV Buick Nailhead
18547236 14527638 18364527
18736542 12634578 18654273 caddy flathead Olds OHV
18726543 12734568 15426378 MEL wedgeblock Ford FE
18436572 15634278 13726548
Caddy OHV Desoto Firedome Chevy smallblock Pontiac Mopar B AMC 1st
& 2nd gen Olds 2nd gen Porsche 928.
The Chevy 4/7 swap simply moves the 90 deg sequence adjacent pairs to
another position. The charging robbing effect is identical except for
being relocated from 5/7 to 2/4.
Cylinders 5/7 and 2/4 both have
the intake ports grouped as pairs with only a divider wall between the
ports so it does not alter the geometry of the 90 deg in firing order
separated ports.
I have never seen a credible explanation as to how this helps anything other than cam makers profits.
One
noticeable thing about the original SBC firing order is that it not
only has most names in the list, it also has all the most performance
oriented names in its list/ball valve.
I wonder what firing order Jaguar,
BMW, MB, Audi, Ferrari, Rover, Aston Martin, Toyota and Nissan use, that
is after they are all converted to the Chev cylinder numbering system.
That is by doing the obvious and starting at the big end journal closest
to the snout as 1 and counting along in sequence to end at 8 closest to
the flywheel.
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