V12 - do cylinders fire in pairs or staggered?

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? :)

Reply to
Dean
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One cylinder at a time. Harley Davidson Motorcycles engine cylinders/pistons both fire at the same time.Unless things have changed lately. cuhulin

Reply to
cuhulin

What is 720 divided by 12?

Reply to
aarcuda69062

Guess what cuhulin? The HD engine fires one cylinder at a time too. If the HD engine had both cylinders firing at the same time, I would imagine that catastrophic engine damage would be the result. The HD 45 degree V Twins connecting rods share a common crankpin. The front cylinder fires, the rear cylinder fires 315 degrees later and the front cylinder starts the cycle over again 405 degrees later. That's what accounts for the HD's distinctive sound, shakiness and sounding like it's out of tune even when running perfectly. As for the V12, I don't know. You can certainly look up firing orders for various V12's on the internet.

Reply to
Lhead

True in as much as the ignition system is a waste spark system.

The firing sequence of a H-D V twin is; fire-crank rotates 315*fire- crank rotates 405*fire-crank rotates 315*fire-crank rotates 405* lather, rinse, repeat.

Reply to
aarcuda69062

I guess I was mistaken.I once saw a program on tv about motorcycles, a guy said Harley Davidson motorcycle engine pistons both fire at the same time.I have never owned a Harley Davidson motorcycle before.Well, I have, but that one was a made in Italy one cylinder Harley Davidson motorbike. cuhulin

Reply to
cuhulin

I think I knew that about Hardley's but I've never owned one. I don't have a spare room/garage to park it in. So I ride a bike I can park on the street, 1975 BMW R90/6. Those bikes had a wasted spark ignition. Altough sometimes I use a substitute electronic ignition that is one cylinder at a time and timed off the crank, not the cam.

So where do you park a V12 car?

Reply to
disston

Right next to the gas pump.

Reply to
gringomasloco

If it's a modern one, the same place you park any other car. The V12s being built these days aren't all that much larger, physically, than a V8 'cause they use smaller pistons. Just from looking at it, you probably won't be able to tell it's a 12 instead of just a big 8 without counting plug wires/injectors. (Unless, of course, it has a "V12" brag molded/stamped/painted on the valve covers or similar, which SHOULD make it fairly obvious...)

The old 40s/50s vintage 12s, on the other hand, might need an extension on your garage to get 'em inside and close the door.

Reply to
Don Bruder

Depends. Here is an article that should help.

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HTH Ben

Reply to
ben91932

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

Reply to
cuhulin

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

Reply to
Steve

Twice as much "oomph" per combustion phase?

Reply to
Don Bruder

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)?

Reply to
Mortimer

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).

Reply to
Steve

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.

Lugnut

Reply to
lugnut

Steve wrote in news:4LCdnR_Lc5llQmnVnZ2dnUVZ snipped-for-privacy@texas.net:

Might there be a gain in torque?

Reply to
Malcolm "Mal" Reynolds

Steve wrote in news:7bednR_nlacMnmjVnZ2dnUVZ snipped-for-privacy@texas.net:

Wouldn't this be the equivalent to a V6?

If you're gonna do

Reply to
Malcolm "Mal" Reynolds

The good old Deltic engine.

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Reply to
Mortimer

Malcolm "Mal" Reynolds wrote in message news:Xns9B37A13F1F77CTBAnoonecarescom@87.106.137.111...

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

Reply to
nanotech

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