I now understand a flat 12 is called a V-12 if it has a flat plane crank. I still think it is confusing to call it a V-12. Would flat crank V8 boxer?
Calling Flat 12 a V-12
- Thread starter borgward
- Start date
I wasn’t aware that anyone was calling a boxer 12 a V-12. Got a reference? Which company?
I think that’s a bit of pedantry...because it was the arrangement of cylinders that led to the nomenclature, not the arrangement of crank pins.
So, my Packard engine is a flat 8 because it has 8 crank pins? Nine main bearings?
Packard called it an eight. Not a flat eight. Nothing flat about that engine, individual crank pins notwithstanding...
So, my Packard engine is a flat 8 because it has 8 crank pins? Nine main bearings?
Packard called it an eight. Not a flat eight. Nothing flat about that engine, individual crank pins notwithstanding...
Yes, its crank ain't flat. The V12 can be spread to 180° or by any angle as it's basically a combination of six cylinders which just share crank pins, but don't really need each other. When Jaguar for a few last years used two Magneti Marellis on its HE engine, people could go on with just one half running (not being too concerned or not taking notice at all, it was said, until the cat took notice for them).
The boxer is basically adding 2+2+2... with lots of main journals.
The boxer is basically adding 2+2+2... with lots of main journals.
Ferarri. The 1993 Testarossa for example.
Maybe they did not want to call it a boxer because that's what Porsche calls their flat engines.
There is a difference between a 180* V or "flat" engine and a boxer.
Boxer engine pistons "box" - they reach TDC or BDC on opposing cylinders simultaneously. In a "flat" or 180* V engine, the pistons share a journal. The 912 engine in the famous Porsche 917 is a "flat" - 180* V.
Boxer engine pistons "box" - they reach TDC or BDC on opposing cylinders simultaneously. In a "flat" or 180* V engine, the pistons share a journal. The 912 engine in the famous Porsche 917 is a "flat" - 180* V.
That is a Testarossa engine, there is nothing V about it. A boxer and flat engine are technically different although both are flat.
Almost the same engine as in the 512BB...which Ferrari itself called...
The Berlinetta Boxer
Not V-12...
Having built both, I would trust Ferrari’s nomenclature on this subject...
it's a 180-degree V12
It uses the same kind of crankshaft a V12 would use.
Nope, it's not a boxer. I was able to find this gif that shows the difference between a boxer crankshaft and that used in a V-engine. The boxer is on top. Ferrari didn't use that boxer crankshaft on either the BB-series or the later Testarossa.
A V-12 can certainly have a flat plane crank. Two different animals. So if there's any confusion it's because people aren't using or understanding proper terminology.
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it's a 180-degree V12
It uses the same kind of crankshaft a V12 would use.
Nope, it's not a boxer. I was able to find this gif that shows the difference between a boxer crankshaft and that used in a V-engine. The boxer is on top. Ferrari didn't use that boxer crankshaft on either the BB-series or the later Testarossa.
My Packard has a crank like the one on top. No shared journals. One journal per rod. That’s a boxer, then?
So, under your definition, what is it?
Further, if Ferrari didn’t use a boxer crank, but called the engine and the car a boxer, what does that say about the definition ?
I’ll be straight up, this definition of flat plane crank and shared, or not, journals, to define “V” or “flat”, is new to me. How recent is it? The simple definition of cylinder arrangement has always been straightforward. This still strikes me as pedantry.
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That's the issue I have with the article, which conflates cylinder configuration with piston/crank configuration, then makes up its own rule that a boxer is a boxer, but not flat, and deserves its own special appellation, while criticizing pedantry but also engaging in it.
Inline, Vee (which notably includes vee-angle), flat, are universally understood to refer to the cylinder orientation, and nothing else.
If one wants to note the distinction between a flat engine with a boxer arrangement, and one that doesn't, that's fine, but that doesn't change the fact that both are flat engines.
What next? V8s with flat cranks as "dual fours" but not V8s? That would be silly, and unnecessary.
While the V only denotes angled banks, the .gif above really showed what defines a boxer.
"Flat" here just meant the same as opposing banks, 180° (or 178°) bank angles. Flat cranks would be independent from it, but have there ever been flat crank twelves, would they make any sense? (12 cylinder boxers don't seem to do either.)
A V12 instead of sharing crank pins can use articulated rods. That way its two cylinder banks don't even use the same stroke length. Primarily aero engines or the typical "Transmash" or "Zvezda" format diesels derived from aero diesels e.g.
Mazda drew its W12 without articulated rods. Regarding the Volkswagen double VR engines (called W12, W16) such have to be loose terms not telling much about rotating assemblies – except that they aren't like the boxers'.
"Flat" here just meant the same as opposing banks, 180° (or 178°) bank angles. Flat cranks would be independent from it, but have there ever been flat crank twelves, would they make any sense? (12 cylinder boxers don't seem to do either.)
A V12 instead of sharing crank pins can use articulated rods. That way its two cylinder banks don't even use the same stroke length. Primarily aero engines or the typical "Transmash" or "Zvezda" format diesels derived from aero diesels e.g.
Mazda drew its W12 without articulated rods. Regarding the Volkswagen double VR engines (called W12, W16) such have to be loose terms not telling much about rotating assemblies – except that they aren't like the boxers'.
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Interesting article.
www.carthrottle.com
Here's Why Ferrari's Old 'Flat-12' Isn't Exactly A Flat-12 At All
The Ferrari Testarossa's engine often leads to a bit of an argument, and it's time to settle it
www.carthrottle.com
+1
Add radial.
I can buy “flat - 12” for the Berlinetta Boxer, which wasn’t a boxer....
so, like squares and rectangles...
All boxers are flat, but not all flat engines are boxers...
But, please don’t call a flat engine a “V”...
so, like squares and rectangles...
All boxers are flat, but not all flat engines are boxers...
But, please don’t call a flat engine a “V”...
