Totally off every topic.

[John Orentas]

Talking four strokes just for now, it is much more than a 'bit of jargon' the fundamental idea that the big end pin is shared by 2 pistons/cylinders is really what makes it possible to fit a big long stroke two cylinder engine into a motorcycle frame, it also allows for a short stiff crankshaft which can withstand higher revs that the more conventional types. Though not well understood it is the asymmetric action of the pistons which everyone who has ridden a V twin will agree gives more torque and pleasing feel than for example a vertical twin engine.

 

Looking through Wikepedia it appears that people are now giving the description 'V' twin to engines that are clearly not (the term V2 is new to me too, probably American) having separated, dedicated crank pins sacrifices that compact nature of the engine though you will doubtless get away with it on a 250cc engine. Of course having 2 big end bearings and a longer crank will inevitably mean a third central main bearing making things even longer and in the case of a two stroke allows seals and a separation wall.

 

Also the V2 will give the option of timing other than 45 or 60 deg. That photo of the Suzuki looks like a near 180 deg offset, I wouldn't know if that is good or bad but I bet is doesn't feel like a 'V' twin.

Edited June 6, 2007 by John Orentas

[Big Steve]

Brilliant contraption that deltic engine, there's one sectioned at York railway museum, an engine without a cylinder head!

[Hairy-Neil]

It's just a hairsplitter's argument.

 

Aren't they the best sort.......

[Phil Speight]

I do understand honest - crankcase compression , porting etc. However , I still think the RGV at least had only one crankshaft and therefore perforce one crankcase. So ; I `m off to look at me mates RGV this very evening and will report back in`t morning.

This is a major sacrifice that I hope you all appreciate becuase every time I see the damn two stroke toy I`m reminded that it is , in fact, probably quicker than my old Jota used to be. Me mate also keeps telling me to get some insurance and borrow it for as long as I want. It`s Japanese, it`s a two stroke, it`s coverd in factory applied Lucky Strike stickers AND I`M NOT A GIRL......................on the other hand the sun shines and I do miss having a bike.

Cheers

Phil

Right - I went and looked - even prodded and poked a bit. The RGV Suzuki is ( was) a two stroke V-twin with two conrods connecting to a common crankshaft in a common crankcase. So it`s a V-twin whichever way you lookat it. I think it probably does not rely on crankcase compression to charge the cylinders .

So there.

Cheers

Phil

[anhar]

Talking four strokes just for now, it is much more than a 'bit of jargon' the fundamental idea that the big end pin is shared by 2 pistons/cylinders is really what makes it possible to fit a big long stroke two cylinder engine into a motorcycle frame, it also allows for a short stiff crankshaft which can withstand higher revs that the more conventional types. Though not well understood it is the asymmetric action of the pistons which everyone who has ridden a V twin will agree gives more torque and pleasing feel than for example a vertical twin engine.

 

Looking through Wikepedia it appears that people are now giving the description 'V' twin to engines that are clearly not (the term V2 is new to me too, probably American) having separated, dedicated crank pins sacrifices that compact nature of the engine though you will doubtless get away with it on a 250cc engine. Of course having 2 big end bearings and a longer crank will inevitably mean a third central main bearing making things even longer and in the case of a two stroke allows seals and a separation wall.

 

Also the V2 will give the option of timing other than 45 or 60 deg. That photo of the Suzuki looks like a near 180 deg offset, I wouldn't know if that is good or bad but I bet is doesn't feel like a 'V' twin.

John, I don't disagree with your description of the internals of the various types of V engines but that is not the point or at least not the point I was trying to establish when agreeing with Tim's criticism of the Wikepedia definition. The fact is that if it has two cylinders in a V, then everyone calls them V twins, whether they have a common crankpin like Harleys or the cylinders are offset to accomodate two crankpins like many Japanese bikes for example.

 

The whole description V twin, or V6 or inline 4 is merely as I said a bit of shorthand jargon to describe the general configurational appearance of the engine for the purposes of easy communication. People want a quick description of an engine and this style delivers that. It is not wrong. Of course those interested can then go into the internal details if required and many do but also many are not interested.

 

I'll bet for example that a large number of Harley owners, especially of recent machines, know that their engines are V twins simply from the appearance, indeed that is a great part of their attraction, but haven't a clue whether or not there is a common crankpin or what the hell a crankpin is anyway.

 

Thus for the sake of brevity, the expression V twin gives a perfect initial and very brief image of what the engine looks like. That's all it purports to do, regardless of the fact that different types of V twin may have different internals.

 

regards

Steve

[John Orentas]

Hi Steve.

 

Well if you are satisfied with the term being a description of the general apperance of an engine that is fine, but for me I happen to take an interest in these matters which I am sure others will consider to be obscure. V twin engines have a very long history dating back to the very earliest days of motor vehicles and the design is one of those fundamentals of classic enginering design, it goes much deeper than what the thing looks like.

 

I do by the way have a background in two stroke racing engines I both built them and raced with them in long circuit Kart racing, hence my somewhat obsessional interest.

[Hairy-Neil]

Hi Steve.

 

.....the design is one of those fundamentals of classic enginering design, it goes much deeper than what the thing looks like......

 

 

I find myself in the unenviable position of having to agree with John again.......

 

 

 

Who cares about my street cred....

[carlt]

I find myself in the unenviable position of having to agree with John again.......

Me too but I never admit it.

 

What does surprise me is that Steve is usually a stickler for correcting sloppy inaccurate use of language.

 

I had heard of V2's though. Didn't the Germans chuck them at us during WW2?

[John Orentas]

I had heard of V2's though. Didn't the Germans chuck them at us during WW2?

 

 

Don't think many of them got this far, but reading that Wikepedia thing I alighted on this:

Junkers Diesel aircraft engines. Take a look at these bloody things, must admit I had never heard of them before.

 

http://www.answers.com/topic/junkers-jumo-205

Edited June 7, 2007 by John Orentas

[anhar]

Me too but I never admit it.

 

What does surprise me is that Steve is usually a stickler for correcting sloppy inaccurate use of language.

 

I had heard of V2's though. Didn't the Germans chuck them at us during WW2?

Yes I am Carl.

 

And yes the Germans did successfully launch V2s at us. Not Harleys though far as I know.

 

Whether the term "V twin" applied to all two cylinder engines in a V formation, whatever the internals, is sloppy or inaccurate is a matter of opinion. I happen to think that for common usage, it is neither but on the contrary is a perfect description. Someone tells me their bike is a V twin and I immediately know what it will look like and so does everyone else including you and John.

 

Those that wish to delve further into the internals will do so but for most people I suspect it doesn't matter. People using the expression are not attempting to give a lecture on the internals, they wish merely to give a quick impression of the type of engine.

 

In fact the only objections are from a tiny cadre of pedants and petrol heads. Most people though are neither so perhaps the expressions need to be modulated according to the intended audience. If it is for people on this board, then clearly no engine can be described without a 900 page manual giving the details of every nut and bolt in it, lest the speaker be condemned for inaccurate terminology. If it is for normal people, then V twin gives a perfect brief description.

 

regards

Steve

[Timleech]

Don't think many of them got this far, but reading that Wikepedia thing I alighted on this:

Junkers Diesel aircraft engines. Take a look at these bloody things, must admit I had never heard of them before.

 

http://www.answers.com/topic/junkers-jumo-205

 

I think that's the design used as the basis for the Commer TS3.

Just trying, feebly, to get somewhere near back on topic, I think Junkers did produce a marine version of the design in sizes down to two cylinders, which would almost have fitted into a narrow boat.

 

Tim

[John Orentas]

I think that's the design used as the basis for the Commer TS3.

Tim

 

 

The Commer was an oddball thing with a single crankshaft, a system of bell-cranks and con-rods connected the pistons and other bits. I would not fancy getting into a plane with one of those things at the front.

[Hairy-Neil]

I think that's the design used as the basis for the Commer TS3.

 

Tim

 

It seems to have the same delayed timing of the second piston, effectively making the pistons themselves act as valves. However, it differs in that it has two crankshafts linked by gears rather than the rocking beam and single crank arrangement of the TS3.

 

 

Those that wish to delve further into the internals will do so but for most people I suspect it doesn't matter. People using the expression are not attempting to give a lecture on the internals, they wish merely to give a quick impression of the type of engine.

 

In rather the same way that many people hoover up with a Dyson.....

 

The Commer was an oddball thing with a single crankshaft, a system of bell-cranks and con-rods connected the pistons and other bits........

 

But it worked, was reliable but, more importantly, made a wonderful sound when working hard......Music to my ears....

[carlt]

Yes I am Carl.

 

And yes the Germans did successfully launch V2s at us. Not Harleys though far as I know.

 

Whether the term "V twin" applied to all two cylinder engines in a V formation, whatever the internals, is sloppy or inaccurate is a matter of opinion. I happen to think that for common usage, it is neither but on the contrary is a perfect description. Someone tells me their bike is a V twin and I immediately know what it will look like and so does everyone else including you and John.

 

Those that wish to delve further into the internals will do so but for most people I suspect it doesn't matter. People using the expression are not attempting to give a lecture on the internals, they wish merely to give a quick impression of the type of engine.

 

In fact the only objections are from a tiny cadre of pedants and petrol heads. Most people though are neither so perhaps the expressions need to be modulated according to the intended audience. If it is for people on this board, then clearly no engine can be described without a 900 page manual giving the details of every nut and bolt in it, lest the speaker be condemned for inaccurate terminology. If it is for normal people, then V twin gives a perfect brief description.

 

regards

Steve

I'm certainly not condemning you Steve. After all there are two sides to every story

[Hairy-Neil]

I'm certainly not condemning you Steve. After all there are two sides to every story

 

PMSL @ Carl.....

[Phil Speight]

Hi Steve.

 

Well if you are satisfied with the term being a description of the general apperance of an engine that is fine, but for me I happen to take an interest in these matters which I am sure others will consider to be obscure. V twin engines have a very long history dating back to the very earliest days of motor vehicles and the design is one of those fundamentals of classic enginering design, it goes much deeper than what the thing looks like.

 

I do by the way have a background in two stroke racing engines I both built them and raced with them in long circuit Kart racing, hence my somewhat obsessional interest.

A friend of mine raced Villiers engined carts years ( and years ) ago . On the front row in the Isle of Man he set off with gusto unaware that his engine was in fact running backwards. Made quite a name for himself in the following 35 seconds or so..........

Incidentally John - how would you describe a "boxer" twin? Flat twin or 180 degree V-twin? I ask because someone ina magazine recently described a Ferrari boxer as a 180 degree V 12

Cheers

Phil

[John Orentas]

A friend of mine raced Villiers engined carts years ( and years ) ago . On the front row in the Isle of Man he set off with gusto unaware that his engine was in fact running backwards. Made quite a name for himself in the following 35 seconds or so..........

Incidentally John - how would you describe a "boxer" twin? Flat twin or 180 degree V-twin? I ask because someone ina magazine recently described a Ferrari boxer as a 180 degree V 12

Cheers

Phil

 

 

Hi Phil.

 

Not familiar with the term at all, I always imagined a 'Boxer Twin' to be one of a pair of cute puppies.

 

180 deg V twin, I can do better than that I had a bike once with a single cylinder radial.

 

Cart is actually spelt Kart.

[anhar]

Well, if you accept Wikipedia there is such a thing as a 180° V engine, despite the fact that this sounds like a total oxymoron. How can two cylinders directly opposed to each other be said to be in a V formation when they don't resemble a V at all? Well according to Wiki, they can be so described when they share a common crankpin, regardless of shape. In fact they say that flat engines with more than eight cylinders are most commonly V engines, hence presumably the Ferrari V12 magazine reference which Phil mentions above.

 

On the other hand the boxer twin, as on BMW R series motorcyles, is not a V engine, having no common crankpin.

 

Just to clarify these distinctions further, it says that in German, the term for a flat engine is boxermotor and this includes both types, common crankpin and otherwise and not just those known as boxers in English, the latter being only the non common crankpin.

 

http://en.wikipedia.org/wiki/Flat_engine

 

and a little BMW R animation http://home.jps.net/~snowbum/techindex.htm

 

For more Wiki fun, it claims that a flat engine is one with horizontal pistons. Okay, so far so good but I'd assumed always that this meant opposing cylinders like a BMW R. But it then goes on to claim that a straight engine canted at 90° is then a flat engine merely because the cylinders are then in a horizontal plane, never mind that they are not opposed to each other. But who uses that definition? To me flat engine is opposing cylinders. A straight canted at 90° is still a straight albeit canted at 90°!

 

So there you are guys, when is a V engine not a V engine? When it doesn't have a common crankpin, never mind the shape of the thing. And when is a straight engine not a straight engine? Confused? Who me?

 

Great stuff.

 

regards

Steve

Edited June 8, 2007 by anhar

[Timleech]

For more Wiki fun, it claims that a flat engine is one with horizontal pistons. Okay, so far so good but I'd assumed always that this meant opposing cylinders like a BMW R. But it then goes on to claim that a straight engine canted at 90° is then a flat engine merely because the cylinders are then in a horizontal plane, never mind that they are not opposed to each other. But who uses that definition? To me flat engine is opposing cylinders. A straight canted at 90° is still a straight albeit canted at 90°!

 

regards

Steve

 

That sounds like a Horizontal engine to me.

Like the Gardner HLW, HLX etc, built mainly to go under bus floors, where the 'H' is for Horizontal.

If Gardners called tham Horizontal, that's good enough for me

 

Tim

[Phil Speight]

That sounds like a Horizontal engine to me.

Like the Gardner HLW, HLX etc, built mainly to go under bus floors, where the 'H' is for Horizontal.

If Gardners called tham Horizontal, that's good enough for me

 

Tim

What`s a bus?

Cheers

Phil

[Sir Nibble]

In fact the only objections are from a tiny cadre of pedants and petrol heads. Most people though are neither so perhaps the expressions need to be modulated according to the intended audience. If it is for people on this board, then clearly no engine can be described without a 900 page manual giving the details of every nut and bolt in it, lest the speaker be condemned for inaccurate terminology. If it is for normal people, then V twin gives a perfect brief description.

I can understand where you are coming from on this but can't really agree. It's a twin. Honda used to make 180degree twins, Triumph made 360degree twins. They looked to be of the same configuration but the difference in crank disposition was fundamental to the characteristics of the engine. To describe a twin as a V twin gives rise to misconceptions about the nature of the engine if both cylinders do not share a common crankpin. These cylinders, being 2 stroke, will be offset at 180 degrees, it will have the characteristics of a parallel twin, quite unlike a traditional V twin. Describe it as a twin and we know it has two cylinders, calling it a V twin gives rise to confusion.

[Hairy-Neil]

What`s a bus?

Cheers

Phil

 

Is similar to a coach but tend to be more basic in build and are used on regular stage work rather than private hire and contracts.....

[John Orentas]

I surprised to see what I have always thought of as a 'T' formation described 'W'.

 

I knew of a chap many years ago who owned one of only two existing Sunbeam racing cars dating back to the 1930's his problem was that his car was missing it's engine, should have been a straight eight if I remember. After several years searching he gave up and as with old boats the convention was that the second best was a contemporary engine of a similar size.

 

He was guided to the MoD and being a well connected sort of bloke he eventually found himself in an enormous hanger which was packed to the roof with mothballed vintage engines. This place was fully staffed, heated and maintained and had been so since the first war, he managed to acquire one of a thousand Napier engines, 24 litres they had been produced for use in airships and were lying there waiting for the craft to make a comeback.

 

The engines were basically a horizontally opposed 12 cylinder with another vertical bank of 6 cylinders positioned on top. An upside-down 'T' or a 'W' if you prefer.

 

Makes you wonder what else is stored away, I did see a World in Action type programme about a huge warehouse full of mule shoes.

Edited June 8, 2007 by John Orentas

[Sir Nibble]

That will be the Napier "LION". It was a very widely used aero engine between the wars. Civil, military, racing.

[Supermalc]

Interesting thread lads. Just read it for the first time to while away a few minutes.

 

Half way though I found myself in agreement with you STEVE, and disagreeing with Carl, Neil and John (I've just read one of John's posts somewhere that I actually agree with, but like Carl, will never admit it )

 

A horizontally apposed engine is one with the cylinders opposite each other in the horizontal plane. A 'V' engine is one where the cylinders are neither horizontal, nor vertical. The term is used to describe the 'look' of the engine from the outside.

 

I'm a bit envious of all your memories though..........to remember all the facts from the different build formats, especially the unusual ones.