Big and small and in between; shows us some wonderful engines!

The Ferrari 512BB 'Berlinetta Boxer' engine is most definitely a flat 12 'boxer'.

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I think he was referring to the opposing pistons not going in and out together--literal interpretation of boxer engine.

Here is the Berlineta Boxer/Testarossa crankshaft:

049_002.gif


And here is a Ferrari Flat-12 competition crank. Different than the street car crank above, but still technically not a 'boxer.'

ferrari211.jpg




By that strict definition this Subaru 12 is said to be a true boxer design like their 4 cylinder.
GFXBRxZZ3YdrXs6WJDTINBzSr8kn3bsbCnjcA6gQwkQ.jpg
 
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I think he was referring to the opposing pistons not going in and out together--literal interpretation of boxer engine.

Here is the Berlineta Boxer/Testarossa crankshaft:

049_002.gif


And here is a Ferrari Flat-12 competition crank. Different than the street car crank above, but still technically not a 'boxer.'

ferrari211.jpg




By that strict definition this Subaru 12 is said to be a true boxer design like their 4 cylinder.
GFXBRxZZ3YdrXs6WJDTINBzSr8kn3bsbCnjcA6gQwkQ.jpg

Yes, I understand exactly what he is referring to. My point is that referring to a flat engine as a V misses the point of using a flat engine design and in particular why Ferrari chose a flat engine.

In a V engine, a genuine V not a mislabeled flat engine, the forces of the moving masses of pistons and con rods on each bank do not balance each other, there being no oppositional symmetry. This can generate vibrations. In most V engines, the power levels involved in normal driving conditions versus the mass of the engine and of the car it is connected to results in no serious vibrations. (Also these days, computer design allows all sort of damping tricks.) In high powered engines in lightweight cars, that is, racing machines or at least ‘hot’ street cars, these vibrations can be significant and weighty damping mechanisms are typically required. Ferrari addressed this problem in their V12 engines in a very unique way… (wait for it).

In a V8 (four cycle) engine, there are eight cylinder-firings in a two-revolution full cycle. It is natural to have the banks separated by 90° = 1/8 of 720° to have even spacings between firings. It would seem natural for a V12 engine to have its banks separated by 60° = 1/12 of 720°. But Ferrari chose 65°! Why? (Aside: In the 1961-1963 F1 seasons, Ferrari used a 120° V6.)

The equally spaced firings in a V engine means that the vibrations caused by the motions of the pistons and con rods are the same all the time, every two-revolution full cycle. But a Ferrari V12 is not a conventional V12. It is really sort of two slant sixes sharing a common crankshaft with each con rod having its own rod bearing journal and counterweights, in contrast to the typical sharing of a journal by two con rods. The 65° separation is possible because there is no sharing of journals and they can be aligned to each individual piston’s place in the firing cycle. The ‘syncopated’ firing helps to break up the vibrations into a larger number of smaller ones. This is incidentally part of the unique sound of a Ferrari V12 at high revs. (The closing of Pink Floyd’s Welcome to the Machine is a Ferrari V12 BTW.) A drawback of this design is that the engine is longer and heavier, having twice the number of journal/counterweight sets and a longer block to accommodate them. (Anyone remember the Long Block Lampredi?) Also, at 65° between banks it is tall.

A flat-12 design would solve a number of problems. With opposed cylinders instead of cylinder banks at asymmetric angles to each other, the vibration situation is greatly reduced, especially when there are a large number of cylinders spreading the individual firings around the cycle. This allows sharing of journals and a shorter lighter crankshaft and block. And of course there is the much lower CG. Avoiding the steering mechanism argued for putting the wide engine behind the driver, an arrangement already extensively used by Ferrari in racers. The Formula 1 cars of the 1960s and the 312PB Enduro racer of the early 1970s had shown the feasibility of a mid-engine flat-12 and Ferrari went ahead with a production road machine in that form: first the 365BB and the quick follow-on 512BB.

The final B in 312PB, 365BB and 512BB all stood for ‘boxer’. Note the quotes around the word as I also used in my original post on this subject. What was meant was that the pistons moved horizontally like a prize fighter’s arms, not the more technical meaning of separate journals for the corresponding pistons on each bank with each piston advancing or returning in sync with its partner. (BTW which one is really more like a boxer’s 1-2 punch?)

It is the distinctive character of a flat engine, the absence of significant vibrations resulting from asymmetric cylinder bank relationships (V8, V10, V12) and the damping weight reduction this allows that distinguishes the flat engine from V type engines. To say it is a 180° V completely misses that point.

As I said earlier, no one distinguished flat from boxer until Ferrari decided to use the word Boxer. No, you can’t do that! Only Porsches are boxers! (Pretty much the case in those days.) The reason that Porsche used the boxer design is that in their original flat 4-cylinder layout, having the piston pairs move in the same direction could cause side to side swings of the light (air cooled) engine block – not a good thing. It is when Porsche got up to 8 cylinders that they went from true boxer (no quotes) to lighter shorter conventional shared journal flat designs. Why? Recall that the additional journals mean a longer heavier engine. While they pretty much have the problem licked today with computerized suspension and stability control systems, the ‘interesting’ (quotes intentional) feature of driving a rear engine Porsche back then was trailing throttle oversteer. AKA the fun things that happen when you go at a good clip into that fast sweeper and it turns out to be decreasing radius. Back off on the gas and physics takes over. With all that mass inertia behind the rear axle, the back end comes out, perhaps quite nastily. Note that the Boxster is a mid-engine design and there is not a whole lot of anything behind the rear axle.

Dividing engines into boxer, V (even when flat!) and inline is not very satisfactory. Non-boxer flat engines are distinct from V’s in their vibration suppression characteristics. And what is a 65° 12-cylinder engine with one journal per piston? (Like a boxer) A V12 or a Siamese twin six? And it all started when Ferrari dared to use the B word. I am unaware of any widespread use of the term ‘boxer’ before that. Even Porsches were called flat 4 etc. And never until then was any flat engine ever called a V.
 
"Air of snobbery". Ha ha, ok, whatever dude. I gave you the pertinent info but, you wish to ignore it. Even Porsche calls what they (917) and Ferrari built "180 degree Vs"
 
Rolls Royce Vulture X24 aircraft engine, early WW2
Basically two old Peregrine V12s wrapped around a single crankshaft

The Manchester bomber used two of these underpowered and unreliable monstrosities
Legend has it that more Manchesters were lost to engine failure than enemy action
When re-equipped with four Merlin V12s instead, the Manchester became the legendary Lancaster bomber

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