I wonder what this will bring at Mecum?

[Bob Kontak]

Originally Posted by javadog

Well, technically it is a 180° V 12, not a boxer. And they did make a 5 L version….

You are killing me, Smalls.



"It's a V 12"
- No one ever

[javadog]

Originally Posted by Bob Kontak

You are killing me, Smalls.

"It's a V 12"
- No one ever

Call it a flat 12, it will make you feel better.

[Bob Kontak]

Originally Posted by javadog

Call it a flat 12, it will make you feel better.

Deal.

Happy holidays!

[Tobra]

Wow, slate grey is a great color

[Tobra]

Originally Posted by javadog

Well, technically it is a 180° V 12, not a boxer. And they did make a 5 L version….

Is the 911 motor a V 6?

[javadog]

Originally Posted by Tobra

Is the 911 motor a V 6?

No, each cylinder has it's own crankpin.

[Tobra]

This is the first time anyone has told me it is not a horizontally opposed, flat 12

Testarossa motor was a 180* V-12

[javadog]

Originally Posted by Tobra

This is the first time anyone has told me it is not a horizontally opposed, flat 12

Testarossa motor was a 180* V-12

A horizontally opposed engine, like a 911 six, has a separate crankpin for each cylinder. This is not really possible with a 12 cylinder engine, as the crankshaft would not be rigid enough. That’s why Porsche paired two cylinders on each crank pin, like the average V engine. Even so, they were so concerned about torsional vibrations in the crankshaft that they took the power takeoff from the middle of the crankshaft, where there’s a “quiet” vibration node, as opposed to the end of the crankshaft.

And yes, all Ferrari flat 12 engines were 180° V 12s.

[rcooled]

Originally Posted by Tobra

This is the first time anyone has told me it is not a horizontally opposed, flat 12

Originally Posted by javadog

A horizontally opposed engine, like a 911 six, has a separate crankpin for each cylinder.

I'd always understood that 'horizontally opposed' just describes the cylinder layout as all being in the same plane, split equally on opposite sides of the crank. Certainly not an expert on these matters though...

Originally Posted by javadog

...they took the power takeoff from the middle of the crankshaft.

[masraum]

Originally Posted by rcooled

I'd always understood that 'horizontally opposed' just describes the cylinder layout as all being in the same plane, split equally on opposite sides of the crank. Certainly not an expert on these matters though...

Flat (squashed V) and boxers are different versions of horizontally opposed engines. I don't think calling a Porsche engine flat is technically correct. I think it could be considered horizontally opposed or a boxer, but flat is different.

https://www.autoevolution.com/news/there-s-a-big-difference-between-a-boxer-and-flat-engine-85305.html

I changed 2 spots in the quote below because the writer was using the term "flat" in two different ways.

The big difference in the headline refers to how each pair of opposing pistons is connected to the crankshaft. < edit >Horizontally opposed < /edit > engines like those used in the 911 to this day are considered boxers because each pair of opposing pistons moves inwards and outwards at the same time. You can visualize the movement of the pistons in the first of two videos attached at the end of this story, or in the form of a professional boxer punching his gloves together before the start of the match. Also worthy of note, this engine configuration does not require a balance shaft or counterweights on the crankshaft.

The non-boxer < edit > horizontally opposed< /edit > engine is best considered a flat V-type engine with the cylinder banks arranged at 180 degrees. Each pair of opposed pistons shares a crankpin, whereas the pistons in a boxer feature individual crankpins. Because of this apparently small difference, one piston moves inward as the other moves outward in the non-boxer design. The second clip is an animation of a flat-12 comprising six pairs firing at every 60 degrees.

The way I believe the writer meant this to read is that there are 2 sorts of horizontally opposed engines, flat and boxer. And the difference between flat and boxer is in the crankshaft configuration and how the piston pairs move relative to each other.

[zakthor]

I got to sit in a real 917 once. So small inside. Cramped like being shut into a travel trunk. Butt on the ground and feet right up at the nose. Felt utterly insane just sitting there.

Its only money 25 million.

[javadog]

Originally Posted by rcooled

I'd always understood that 'horizontally opposed' just describes the cylinder layout as all being in the same plane, split equally on opposite sides of the crank. Certainly not an expert on these matters though...

That’s not the crankshaft output gear in your photo.. See the photos below. The output gear drives a short layshaft on the bottom of the engine which takes power to the clutch. The oil pump drive is off the other side.

There is a second layshaft at the top which drives the cooling fan, distributors, etc.

[javadog]

Here’s a few photos of a 917 engine opened up and cut away in places:

https://porschebahn.wordpress.com/2011/06/17/exploded-view-of-porsche-917-12-cylinder-engine/

[Tervuren]

Horizontally Opposed seems to be what "boxer" is slang for.
The cylinders move in opposition away and towards.
If one drops the opposed and just uses horizontal, or flat, it becomes ambiguous between a boxer or a flat V.

Originally Posted by masraum

The way I believe the writer meant this to read is that there are 2 sorts of horizontally opposed engines, flat and boxer. And the difference between flat and boxer is in the crankshaft configuration and how the piston pairs move relative to each other.

[javadog]

Originally Posted by Tervuren

Horizontally Opposed seems to be what "boxer" is slang for.
The cylinders move in opposition away and towards.
If one drops the opposed and just uses horizontal, or flat, it becomes ambiguous between a boxer or a flat V.

No, it is just a term for engines with the cylinder banks directly opposite on another, as opposed to another arrangement of cylinders, like a v-engine, an inline engine, a radial engine, etc.

A boxer is only one type of horizontally opposed engine.

A flat engine is slang for a horizontally opposed engine.

[Tervuren]

What are modern flat engines that aren't cylinder banks opposite each other?
I've never seen a flat radial, but perhaps they were a thing.
I suppose there could also be horizontal cylinders in offset planes, but haven't seen one of those either.

Originally Posted by javadog

No, it is just a term for engines with the cylinder banks directly opposite on another, as opposed to another arrangement of cylinders, like a v-engine, an inline engine, a radial engine, etc.

A boxer is only one type of horizontally opposed engine.

A flat engine is slang for a horizontally opposed engine.

[javadog]

Originally Posted by Tervuren

What are modern flat engines that aren't cylinder banks opposite each other?

Like what, exactly? I'm not aware of any offhand.

[Tobra]

VR6 VW motor is like that. Makes for thick cylinder walls and tolerance for forced induction

[javadog]

Originally Posted by Tobra

VR6 VW motor is like that. Makes for thick cylinder walls and tolerance for forced induction

It's a V6, with a 15 degree V angle and a siamesed block. Basically, they took an inline 6 and shortened it to fit in their cars by offsetting every other cylinder.

Clever design, one of my favorite engines. Made a fabulous noise. If my R32 had had higher profile tires and a slightly different seat, I might still have it.

[stevej37]

I'm guessing $30.1 mil