V12 - do cylinders fire in pairs or staggered?

Back in the 1960s a used car lot down town had an old 12 cylinder
Lincoln car for sale, for $3,500.I tried the car out around the
block.The car didn't seem to have much power.Across the street from that
used car lot there was another used car lot.They had a 1953 Corvette car
for sale for $3,500.
cuhulin

Dean wrote:
> I've always wondered this, whether in a V12, all the cylinders fire
> one by one or in pairs? Any 750i/S600 owners out there?

I don't know of any common engine, from 4 cylinders to 20, that fires
cylinders simultaneously. What on earth would be the point?

In article >,
Steve > wrote:

> Dean wrote:
> > I've always wondered this, whether in a V12, all the cylinders fire
> > one by one or in pairs? Any 750i/S600 owners out there?
>
> I don't know of any common engine, from 4 cylinders to 20, that fires
> cylinders simultaneously. What on earth would be the point?

Twice as much "oomph" per combustion phase?

--
Don Bruder - - If your "From:" address isn't on my whitelist,
or the subject of the message doesn't contain the exact text "PopperAndShadow"
somewhere, any message sent to this address will go in the garbage without my
ever knowing it arrived. Sorry... <http://www.sonic.net/~dakidd> for more info

"Don Bruder" > wrote in message
...
> In article >,
> Steve > wrote:
>
>> Dean wrote:
>> > I've always wondered this, whether in a V12, all the cylinders fire
>> > one by one or in pairs? Any 750i/S600 owners out there?
>>
>> I don't know of any common engine, from 4 cylinders to 20, that fires
>> cylinders simultaneously. What on earth would be the point?
>
> Twice as much "oomph" per combustion phase?

True, but offsetting one bank of cylinders by half a crankshaft revolution
means you get 12 small surges of power rather than 6 large ones, so the
engine is smoother: the explosions from one bank fill in the gaps between
the explosions on the other bank.

Silly question: in a 4-cylinder engine, it's normal to have the pistons at 0
or 180 degrees on the crank shaft, so two are at the top of the travel (one
about to do induction, the other about to do power) when the other two are
at the bottom of the travel. But would it make the engine smoother if the
pistons were at 0, 90, 180 and 270 degrees (though in a random sequence to
avoid a travelling wave)?

Don Bruder wrote:
> In article >,
> Steve > wrote:
>
>> Dean wrote:
>>> I've always wondered this, whether in a V12, all the cylinders fire
>>> one by one or in pairs? Any 750i/S600 owners out there?
>> I don't know of any common engine, from 4 cylinders to 20, that fires
>> cylinders simultaneously. What on earth would be the point?
>
> Twice as much "oomph" per combustion phase?
>

Which only makes the power delivery less smooth. If you're gonna do
that, one bigger cylinder makes more sense. Adding cylinders and making
them fire sequentially, even if the spacing between firings isn't even
(ala the Dodge Viper V10) makes for less vibration and torsional loading
on the crank than fewer, bigger power pulses. There does come a point
where crank length makes adding cylinders impractical, but a V12 isn't
close to that. EMD made a 20-cylinder medium-speed diesel for
locomotives and ships for a while in the 70s and 80s, but it proved less
reliable than a higher-powered V16 because the crank and case (there
isn't really a "block" in that kind of engine) had flexing problems.
Especially in locomotives, it was pretty good in ships (I've ridden on a
ship powered by 2 of them).

Steve > wrote in
:

> Dean wrote:
>> I've always wondered this, whether in a V12, all the cylinders fire
>> one by one or in pairs? Any 750i/S600 owners out there?
>
> I don't know of any common engine, from 4 cylinders to 20, that fires
> cylinders simultaneously. What on earth would be the point?
>
>
>

Might there be a gain in torque?

Steve > wrote in
:

> Don Bruder wrote:
>> In article >,
>> Steve > wrote:
>>
>>> Dean wrote:
>>>> I've always wondered this, whether in a V12, all the cylinders fire
>>>> one by one or in pairs? Any 750i/S600 owners out there?
>>> I don't know of any common engine, from 4 cylinders to 20, that fires
>>> cylinders simultaneously. What on earth would be the point?
>>
>> Twice as much "oomph" per combustion phase?
>>
>
> Which only makes the power delivery less smooth.


Wouldn't this be the equivalent to a V6?


If you're gonna do
> that, one bigger cylinder makes more sense. Adding cylinders and making
> them fire sequentially, even if the spacing between firings isn't even
> (ala the Dodge Viper V10) makes for less vibration and torsional loading
> on the crank than fewer, bigger power pulses. There does come a point
> where crank length makes adding cylinders impractical, but a V12 isn't
> close to that. EMD made a 20-cylinder medium-speed diesel for
> locomotives and ships for a while in the 70s and 80s, but it proved less
> reliable than a higher-powered V16 because the crank and case (there
> isn't really a "block" in that kind of engine) had flexing problems.
> Especially in locomotives, it was pretty good in ships (I've ridden on a
> ship powered by 2 of them).
>
>
>
>
>

"lugnut" > wrote in message
...
> There is one loco engine I remember that could be called firing 2
> simultaneously. It fired 2 pistons but, only one cylinder. Was used
> extensively in the 30's, 40's & 50's. Biggest one I saw or worked on was
> a 10
> cylinder. IIRC, the could be built with as many as 20 cylinders. I think
> they
> may still be building them for industrial and marine applications. You
> probably
> know which one I am talking about.

The good old Deltic engine. http://en.wikipedia.org/wiki/Napier_Deltic

Malcolm "Mal" Reynolds > wrote in
message 11...
> Steve > wrote in
> :
>
> > Dean wrote:
> >> I've always wondered this, whether in a V12, all the cylinders fire
> >> one by one or in pairs? Any 750i/S600 owners out there?
> >
> > I don't know of any common engine, from 4 cylinders to 20, that fires
> > cylinders simultaneously. What on earth would be the point?
> >
> >
> >
>
> Might there be a gain in torque?

ok for your information yes some industrial engine where made that way

fairbanks morse oppose piston is one working on diesel 2 cycle principle

allischalmer dozer tractor one of there series worked that way it was a 6
cyl the first model was a normal sequencing firing order but the other secon
model was the same 6 cyl but firing a bank of 2 cyl at the same time the cam
was different
it was call a "BIG BANG ENGINE" the advantage of a big bang engine was that
it gave way more low end torque then the standard firing sequence

"Mortimer" > writes:

> "Don Bruder" > wrote in message
> ...
>> In article >,
>> Steve > wrote:
>>
>>> Dean wrote:
>>> > I've always wondered this, whether in a V12, all the cylinders fire
>>> > one by one or in pairs? Any 750i/S600 owners out there?
>>>
>>> I don't know of any common engine, from 4 cylinders to 20, that fires
>>> cylinders simultaneously. What on earth would be the point?
>>
>> Twice as much "oomph" per combustion phase?
>
> True, but offsetting one bank of cylinders by half a crankshaft revolution
> means you get 12 small surges of power rather than 6 large ones, so the
> engine is smoother: the explosions from one bank fill in the gaps between
> the explosions on the other bank.
>
> Silly question: in a 4-cylinder engine, it's normal to have the pistons at 0
> or 180 degrees on the crank shaft, so two are at the top of the travel (one
> about to do induction, the other about to do power) when the other two are
> at the bottom of the travel. But would it make the engine smoother if the
> pistons were at 0, 90, 180 and 270 degrees (though in a random sequence to
> avoid a travelling wave)?
>
>

Yamaha has a cross plane crank four cylinder engine:

Check the demo at:

http://www.yamaha-motor.com/sport/msite/micro_v1.aspx