Talk:Flat-twelve engine

Suggestion that flat 12 engine be merged with Flat-12 page
There has been a suggestion that flat 12 engine be merged with Flat-12 page, but I see that no one has discussed this yet.


 * Support - The pages are obviously about the same thing. The flat 12 engine page doesn't seem to add any additional value to Wikipedia and the Flat-12 name is consitant with the Flat-4, Flat-6 and Flat-8 pages. The flat 12 engine page should be changed to a redirect. -- Xagent86 (Talk | contribs) 10:33, 17 February 2007 (UTC)


 * I added the info from the flat 12 engine page - mainly about the Jiotto Caspita - and since no-one else seems to object to the merge, the pages should be merged. --Xagent86 (Talk | contribs) 12:10, 31 March 2007 (UTC)


 * Merge is now complete. --Xagent86 (Talk | contribs) 12:33, 31 March 2007 (UTC)

Suggestion that calling a flat engine ANY kind of a V design be stopped, it is technically inaccurate
The V in regards to a V-6, V-8, V-whatever, refers to the configuration of the cylinders. In a V engine, the cylinders are in a V shape, hence the designation. Calling a flat engine a boxer engine by default is also wrong, as a boxer engine is a type of flat engine, but not all flat engines are boxer engines. It is like the old adage, a robin is a bird, but a bird isn't necessarily a robin. The term flat engine refers to an even number (usually) in total of cylinders that are flattened out, opposed to each other in some way, either with a central crank and opposite sided cylinder heads, or two crankshafts and no cylinder "head" to speak of, but a shared combustion chamber. An engine with any number of cylinders all lined up, even if the engine itself is laid over on it's side, is still an inline design, because the cylinders are all IN LINE with each other.

https://www.autoevolution.com/news/there-s-a-big-difference-between-a-boxer-and-flat-engine-85305.html shows that the boxer style flat engine has individual crank journals for each connecting rod associated with each piston. That means that each opposing cylinder/piston pair could be aligned to be on the same exact point in the stroke cycle or variations up to and including totally opposite from each other, but would still be a "boxer" engine. Where with the other generally accepted flat engine layout, the one where the connecting rods share a crank journal, the opposing cylinder pairs would have their respective pistons in opposite points within each cylinder at the same time, with the obvious overlap as each piston is traveling in or out. 32.212.104.223 (talk) 18:19, 9 July 2017 (UTC)

Edit: Actually, the term "horizontally opposed" when referring to this layout IS accurate, as the cylinder banks are on opposing sides of the crankshaft in many cases, AND they are horizontally on the same level. I am not 100% sure that there are not flat engines that have 2 separate crankshafts and a shared combustion chamber between two opposing pistons. But trying to call all flat engines boxer engines is as incorrect. 32.212.104.223 (talk) 18:30, 9 July 2017 (UTC)
 * Those engines exist, but they're a form of opposed piston engine and so are not called "flat engines", just to keep them clearly separate. Note that not all opposed piston engines have two crankshafts though, and they're often vertical.
 * A flat engine is also called a "180º V engine". This is because it's technically indistinguishable from a V engine. A "179º V engine" would presumably meet your rigorous condition that it be "V shaped", yet one would be hard-pressed to tell them apart without a protractor. In contrast, a boxer engine has a clear technical difference. Although it's not impossible (and I'm sure someone somewhere must have tried it, probably an early two-stroke), I know of no V-shaped boxer engines.
 * I have no strong feeling over flat vs. 180ºV - both terms are used. But boxer and opposed piston are specific types, and would be wrong for the general term. As it's so easily confused, horizontally opposed is also a problem and ought to be avoided, even though that's used too. Andy Dingley (talk) 19:51, 9 July 2017 (UTC)


 * Actually, it is VERY distinguishable from a V engine, both visually and technically. The V refers to the physical layout of the cylinder banks, NOT how the rods connect to the crankshaft.  The boxer, as far as I know, by design, IS a flat engine, as are many other flat engine designs.  But what differentiates it from other flat engines is the connecting method of the pistons to the crankshaft.  It uses the separate crank journals.  You can do the same thing with V engines, it doesn't now somehow make them a boxer engine.  They are still V engines because of the V.  All different names for them, horizontally opposed, opposing pistons, they are all still flat engines.  And technically, yes, an engine with an angle of 179º COULD still be called a V engine at that point, but I am not going to find a protractor.  My specific issue is with calling ANY type of flat engine design a 180º V.  That's it.  It is physically impossible.  It IS possible to make a V shaped, by your definition here at least, Boxer engine, using the separate crankshaft journals as the basis, I presume so anyway.  You could set it up so that the crank had pretty much an infinite variation of when each piston was at whatever point in the combustion order, in theory.  The problem would come when vibrations set up from bad timing/firing combinations and a bunch of other stuff happened.  I have heard that it could shake an engine and possibly the vehicle itself apart too without some sort of external balancing agent.
 * The problem comes when people start to presume that all flat engines are boxer engines, when that just isn't the case.
 * But back to your "and so are not called flat engines". If they are flat engines, then they are flat engines.  If the cylinder banks are on the same relative horizontal (or vertical) plane, then they are a flat engine design.  32.212.104.223 (talk) 20:12, 9 July 2017 (UTC)
 * The issue is sourcing. I can easily source "180º V engine", but I'm still waiting on these V-shaped boxer engines, or on "A flat engine isn't a V because it's not V shaped". Andy Dingley (talk) 20:58, 9 July 2017 (UTC)

Berlinetta Boxer and the non-boxer engine
A works drawing of the Ferrari 'boxer' crank, confirming that it isn't a boxer engine. Andy Dingley (talk) 22:25, 9 July 2017 (UTC)

Subaru 1235 - Flat twelve oder Boxer?
According to its own Wikipedia article, the Subaru 1235 F1 engine, also mentioned in this article, was a Boxer engine, not a flat 12 with shared crank journals for opposing pistons. Does anyone have more information on this engine? — Preceding unsigned comment added by Lolle42 (talk • contribs) 14:25, 27 April 2020 (UTC)