# Curious about the I6 vs Slant 6



## Ryan525i (Feb 15, 2006)

How does BMW actually concider it a I6 when in fact it is a slant 6... I thought the I6 was like the old Jaguars the was actually called a striaght 6.


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## Rich_Jenkins (Jul 12, 2003)

Ryan525i said:


> How does BMW actually concider it a I6 when in fact it is a slant 6... I thought the I6 was like the old Jaguars the was actually called a striaght 6.


Why do you think it is a "slant 6"?


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## philippek (Jul 31, 2003)

wingspan said:


> Why do you think it is a "slant 6"?


probably because the engine is mounted at a 45-degree angle (or is it 30?)...still a str8 6 though.

Kind of the equivalent of calling a boxer engine a "180-degree V"


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## xspeedy (Apr 10, 2003)

I6 doesn't = straight six. I6 is a more general term whereby straight and slant are more specific.


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## Penforhire (Dec 17, 2005)

I'd still consider it an in-line six, regardless of the overall cant.


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## LA525iT (Oct 27, 2003)

philippek said:


> Kind of the equivalent of calling a boxer engine a "180-degree V"


:rofl:


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## Fast Bob (Jun 4, 2004)

Penforhire said:


> I'd still consider it an in-line six, regardless of the overall cant.


Exactly....when there`s six cylinders, arranged one behind the other, it`s a "straight-six", "inline-six", or "slant-six" (pioneered by Chrysler in 1960 for economy of packaging under lower hoodlines, eventually copied by others, including BMW)....it`s all the same thing.

Regards,
Bob


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## Ryan525i (Feb 15, 2006)

I understand the fact that all the pistons are right behind it makes it a inline. just everytime I take it to a shop the call it a slant six because of the angle it is.. Just curious... to me it doesnt really matter just wanted to see if I could maybe get some input on why or what the diffrence is.


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## Rich_Jenkins (Jul 12, 2003)

Ryan525i said:


> I understand the fact that all the pistons are right behind it makes it a inline. just everytime I take it to a shop the call it a slant six because of the angle it is.. Just curious... to me it doesnt really matter just wanted to see if I could maybe get some input on why or what the diffrence is.


Gotcha.

I actually had a Dodge Dart ('63) bought used when I was a poor penniless student. It had a six-cyl engine specifically called a "slant 6", which is why I asked.

I've only ever heard a bimmer engine denoted as an "inline 6" or "I6", so was curious.


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## Ryan525i (Feb 15, 2006)

lmao, think i filled your old poor penniless shoes


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## Fast Bob (Jun 4, 2004)

Ryan525i said:


> I understand the fact that all the pistons are right behind it makes it a inline. just everytime I take it to a shop the call it a slant six because of the angle it is.. Just curious... to me it doesnt really matter just wanted to see if I could maybe get some input on why or what the diffrence is.


Chrysler trademarked the term "Slant Six" to front their innovation, they were the first to do it. The term later became a generic reference, similar to "Kleenex", "Simonize","Xerox", etc.

Regards,
Bob


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## Bart001 (Apr 9, 2005)

Fast Bob said:


> Chrysler trademarked the term "Slant Six" to front their innovation, they were the first to do it. The term later became a generic reference, similar to "Kleenex", "Simonize","Xerox", etc.
> 
> Regards,
> Bob


None of Kleenex, Simonize or Xerox are generic. Each is a registered trademark.


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## Penforhire (Dec 17, 2005)

Darts were cool, especially the push-button tranny.


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## Fast Bob (Jun 4, 2004)

Bart001 said:


> None of Kleenex, Simonize or Xerox are generic. Each is a registered trademark.


DUH....Have`nt you ever heard someone say "Hand me a Kleenex", "I just Simonized my car", or "Please Xerox this letter"???? REGARDLESS of the actual product being used???? The term "Slant Six" also falls into this category.

Regards,
Bob


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## Rob325_in_AZ (Oct 22, 2004)

Alright, what am I missing?  I've never heard of a 'slant-6' before. I always assumed an I-6 had the cylinders going straight up and down, perpendicular to the ground (at least left to right, I know they'll tilt back just a bit because the drivetrain may slope downwards a bit.)


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## Pinecone (Apr 3, 2002)

Well you haven't looked carefuly under the hood of your own car. The engine is canted sideways about 30 degrees. So it is basically 1/2 of a V12.

Slant 6 is a specific name of a CHysler engien in the 60s as has been mentioned.

And when I worked for Xerox MANY years ago, they were very hard on us using Xerox as the brand name ONLY, and that the process was xerographic copying. Aspirin used to be a trademark name. And even today, most people say Xerox something, when most of the copiers are not actually Xerox products.

Also why if you go into a resturant and order a coke, many times (should be ALL the time) they may say we have Pepsi, is that OK. Coke is a registered trademark adn the company is making sure it does not become generic.


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## xspeedy (Apr 10, 2003)

I used to drive my father's old 1972 Dart Swinger for a while. It had a 225 CID Slant 6. I think that equates to about 3.7 liters or so. It wasn't fast, but the engine lasted a long, long time.


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## 300B (Sep 28, 2005)

The Chrylser slant six was an awesome engine,durable as hell.


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## F1Crazy (Dec 11, 2002)

Fast Bob said:


> (pioneered by Chrysler in 1960 for economy of packaging under lower hoodlines, eventually copied by others, including BMW)....it`s all the same thing.
> 
> Regards,
> Bob


Hmm, 300SL Gullwing introduced in 1954 had an I6 canted at 50 degrees :dunno:


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## Fast Bob (Jun 4, 2004)

F1Crazy said:


> Hmm, 300SL Gullwing introduced in 1954 had an I6 canted at 50 degrees :dunno:


Yeah, but that little fact got lost in the details....the enormity of the Gullwings`s impact just knocked everyone flat on their collective asses (BTW, I saw one not long ago, still has the original paint from 1955!) Of course, American automakers paled by comparison....Chrysler`s big innovations were torsion-bar front suspension, pushbutton transmissions, and the Slant Six....

Regards,
Bob


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## gojira-san (Mar 1, 2004)

300B said:


> The Chrylser slant six was an awesome engine,durable as hell.


Yep, there were a lot of clam boats running slant-sixes in them when I was a kid. With some simple conversions, made for a reliable marine power plant.


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## kyfdx (Aug 4, 2003)

I thought that BMW called it the L-6.. ?

With the cylinders being the slanted side of a triangle that connects the two end points of a capital L

(imagine looking at the engine from the firewall).


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## Salvator (Oct 14, 2003)

Fast Bob said:


> Chrysler`s big innovations were torsion-bar front suspension, pushbutton transmissions, and the Slant Six....


I thought I read somewhere that Torsion-bar suspensions had to be licensed from Porsche (Ferdinand, that is) as they were originally used on the VW Beetle in 1938... :dunno:


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## DustyWheeler (Apr 17, 2006)

Straight sixes are any engines with the cylinders in a straight line, regardless of cant or lean angle.
"Slant" six is just a slightly more specific term, telling us that the block is angled over somewhat to lower the bonnet line.

The biggie is this...."Inline" specifies the crankshaft / chassis centreline relationship, distinguishing the difference between the classic BMW placement, and the "transverse" six (which can be straight six OR V6 ), as in almost all front wheel drives.

Porches have Flat six engines, for example, but these are still "Inline" sixes.

A Harley has a transverse V-twin, (and so does Ducati - although slanted at a different angle) while Moto Guzzi's have inline V-twins.

JM 0.02


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## bmw325 (Dec 19, 2001)

DustyWheeler said:


> .
> 
> The biggie is this...."Inline" specifies the crankshaft / chassis centreline relationship, distinguishing the difference between the classic BMW placement, and the "transverse" six (which can be straight six OR V6 ), as in almost all front wheel drives.


I disagree on that point. "Inline" refers to the fact that the cylinders are all in a row. "Longitudinal" would be the term used to describe the placement of the engine in the chassis (as opposed to "transverse").

So, a BMW 6 cylinder engine is:
-has cylinders in an inline configuration (you might also say "straight 6").
-mounted at an angle (or "slant" to use the old Chrysler term)
-is situated longitudinally in the engine bay


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## Fast Bob (Jun 4, 2004)

bmw325 said:


> I disagree on that point. "Inline" refers to the fact that the cylinders are all in a row. "Longitudinal" would be the term used to describe the placement of the engine in the chassis (as opposed to "transverse").
> 
> So, a BMW 6 cylinder engine is:
> -has cylinders in an inline configuration (you might also say "straight 6").
> ...


I agree totally with your asessment....I have *never* heard of, nor would I ever refer to,a Boxer engine as "Inline", regardless of it`s crankshaft orientation. Boxers have a specific term to describe them....they`re "Horizontally-Opposed".

Regards,
Bob


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## DustyWheeler (Apr 17, 2006)

bmw325 said:


> I disagree on that point. "Inline" refers to the fact that the cylinders are all in a row. "Longitudinal" would be the term used to describe the placement of the engine in the chassis (as opposed to "transverse").
> 
> Hmmmm...Gotta give you points for that.
> 
> Technically, I agree.. but if you trawl through a pile of car / bike mags, you'll be lucky to find longitudinal as a descriptive term.


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## Penforhire (Dec 17, 2005)

Not really. In a twist of fate (considering the board we're on and the subject at hand), and IIRC, BMW's K-bike changed from an unusual longitudinal I4 (although earlier K75's were I3) to a transverse I4 (standard for most I4's) in the newer model. I believe transverse and longitudinal are still the terms commonly used.


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## WAM (Jan 30, 2002)

philippek said:


> Kind of the equivalent of calling a boxer engine a "180-degree V"


A 'boxer' engine is slightly different from a 'flat' or 180 degree V engine, in that the pistons of any two opposing cylinders both move in towards, or out from the crankshaft at the same time. Each of the two cylinders has an opposing throw on the cranshaft, so a boxer six would have 6 throws on the crankshaft.

A flat 6, would have only three throws on the crankshaft, so any two opposing cylinders would move in the same direction, i.e. one cylinder would be moving towards the crankshaft and the other would be moving away.

Therefore, a boxer engine's masses are balanced, at least at the two opposing cylinder level.


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## Pinecone (Apr 3, 2002)

And a Porsche engine is actually a V-6 that has a 180 degree V angle, not an inline engine.

I can't remember the German word that would denote inline, probably starts with L. 

And BTW, what car has a transverse I-6????


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## F1Crazy (Dec 11, 2002)

Pinecone said:


> And BTW, what car has a transverse I-6????


I think Volvo had a transverse I-6. :dunno:


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## Fast Bob (Jun 4, 2004)

F1Crazy said:


> I think Volvo had a transverse I-6. :dunno:


As an aside, Honda`s CBX (motorcycle) of the late `70s also had a transverse inline six....

Regards,
Bob


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## bmw325 (Dec 19, 2001)

F1Crazy said:


> I think Volvo had a transverse I-6. :dunno:


Yep-- the S80 has a transverse I6. I remember reading that volvo had to develop a very compact transmission to be able to fit the whole thing transversely.


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## mullman (Jan 5, 2006)

Yes, a boxer engine has the conrods on opposing throws of the crankshaft.
The pistons appear to "box" each other as they go in.

A pics pics here from rebuilding a vintage BMW twin:


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## khausler (Jul 13, 2004)

Mullman, I thought I recognized the Observer as your drop cloth, noticed your location, and out of curiosity looked at your home page and your boat projects. Small world - my wife and two girls and I also live in Beverly Crest.


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## mullman (Jan 5, 2006)

khausler-

small world indeed!

ssshhh - I'm the guy bending the rules building small boats for the lake.
The bylaws only say "No swimming or wading", and I plan on doing neither.

PM sent...


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## andy_thomas (Oct 7, 2002)

Pinecone said:


> And a Porsche engine is actually a V-6 that has a 180 degree V angle, not an inline engine.
> 
> I can't remember the German word that would denote inline, probably starts with L.


Reihenmotor, or perhaps just Reihen (in-line).

It's for this reason that everyone thought that the new code for the Valvetronic six was 'R6', some folks even go so far as to tell us intellectual paupers that this was a departure from the usual Mxx naming convention, and all the while R6 in German just meant "inline six" in English. Bless 


> And BTW, what car has a transverse I-6????


Alex mentioned the Volvo S80. I think the XC90's straight-six petrol engine is transverse, too.

I have heard of slant six of course, being a car nut and despite being a Pom. But it has no real place outside of Chrysler talk - I've never heard it used elsewhere. Engine configurations are traditionally independent of the way they happen to be mount in the car (what would happen if you took a 225ci /6 out of an old Dodge and shoved it bolt upright in a motorboat?).


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## andy_thomas (Oct 7, 2002)

bmw325 said:


> I disagree on that point. "Inline" refers to the fact that the cylinders are all in a row. "Longitudinal" would be the term used to describe the placement of the engine in the chassis (as opposed to "transverse").


Correct - this is the engineering designation, still. Although the term "longitudinal" seems to be rapidly becoming archaic, as the market's need to appreciate even basic engineering attributes dies away.

The nice thing about a longitudinal four in a BMW is that of course it's essentially mid-engined. 


> So, a BMW 6 cylinder engine is:
> -has cylinders in an inline configuration (you might also say "straight 6").
> -mounted at an angle (or "slant" to use the old Chrysler term)
> -is situated longitudinally in the engine bay





> I'll buy that


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