The straight 6 is back

[935k3]

In a Mercedes. Mercedes Six

[THarrison351]

And 'lectric too!

[MrObsessive]

I'd sure like to see straight sixes make a comeback across the board! While I like dual cam sixes like I have in my Challenger, I like the smoothness that comes with that straight six, not to mention the better proportions it gives a car. Gets rid of those 'front wheels too close to the door' appearance.  

[Classicgas]

But they covered it in plastic. Plus the car to me has no style. Just another jelly bean.

[espo]

Interesting to see that Mercedes is going with an inline 6 program. A lot of money and R & D had to go into the development of this engine. BMW has in the last couple of years also has developed inline 6's again. One of the biggest inherit advantage to the inline engine is the smooth power delivery. One of the past problems was even fuel distribution, but with modern Fuel Injection systems I don't see where that would be a problem any longer.   

[Rob Hall]

25 minutes ago, espo said:

Interesting to see that Mercedes is going with an inline 6 program. A lot of money and R & D had to go into the development of this engine. BMW has in the last couple of years also has developed inline 6's again. 

BMW never went away from inline 6s.   I've read that FCA may be working on a new inline 6 for Jeep. 

Edited October 16, 2018 by Rob Hall

[espo]

Just now, Rob Hall said:

BMW never went away from inline 6s.   I've read that FCA is working on a new inline 6 for Jeep. 

I would appreciate any additional information on the Jeep. We have an '09 Wrangler with 99k and are thinking can we afford a new one or put an LS motor in our old one. We had a TJ years ago with the 4.0 liter 6 and it was a good setup at that time. 

[Rob Hall]

5 minutes ago, espo said:

I would appreciate any additional information on the Jeep. We have an '09 Wrangler with 99k and are thinking can we afford a new one or put an LS motor in our old one. We had a TJ years ago with the 4.0 liter 6 and it was a good setup at that time. 

I read an article about it on Allpar last month..still just a rumor at this point, but it seems plausible.    I liked the 4.0 6 my WJ had.  Though the 3.6 DOHC V6 in my WK2 has more power and torque. 

https://www.allpar.com/mopar/V6/tornado.html

Edited October 16, 2018 by Rob Hall

[espo]

Thanks for the information. I'll watch and see how this goes. As far as the Wrangler goes we would need something with a lot of low end torque since it sees some pretty steep rock climbing when we go Wheel'n.  

[Ace-Garageguy]

34 minutes ago, Rob Hall said:

... I've read that FCA may be working on a new inline 6 for Jeep. 

FCA ought to look seriously at licensing GM's 4.2 Vortec inline-six...if the tooling still exists. Would save tons of development dollars, and it wouldn't be the first time a GM engine ended up in a Jeep. AND...it was developed specifically for 4WD applications, with a front axle passthrough in the sump.

Edited October 16, 2018 by Ace-Garageguy

[Rob Hall]

4 minutes ago, Ace-Garageguy said:

FCA ought to look seriously at licensing GM's 4.2 Vortec inline-six...if the tooling still exists. Would save tons of development dollars, and it wouldn't be the first time a GM engine ended up in a Jeep.

That engine hasn’t been in production in a decade...

I doubt if FCA would be interested in an obsolete GM engine. 

Edited October 16, 2018 by Rob Hall

[Ace-Garageguy]

9 minutes ago, Rob Hall said:

That engine hasn’t been in production in a decade...

I doubt if FCA would be interested in an obsolete GM engine. 

What, exactly, makes it "obsolete"?

It's a solid platform, uses the most advanced aluminum casting technology, already had variable exhaust cam timing, and is easily adapted to current engine management peripherals.

Again, what's the "obsolete" part?

The engine wasn't phased out because there was anything wrong with it...GM just moved away from building vehicles that could package an inline 6.

It's doubtful that starting from a clean sheet would produce a superior block, head, or mechanical internals.

Edited October 16, 2018 by Ace-Garageguy

[Rob Hall]

4 minutes ago, Ace-Garageguy said:

What, exactly, makes it "obsolete"?

It's a solid platform, uses the most advanced aluminum casting technology, already had variable exhaust cam timing, and is easily adapted to current engine management peripherals.

Again, what's the "obsolete" part?

It's long out of production, it would probably not be cost-effective to get it to meet 2020 emission standards, and the tooling has probably been scrapped.   I think it's better for FCA to develop their own products than use someone else's castoffs... now if it were a current engine, they could probably make a business case for it or a JV of some sort. 

Why would any company want to use some other company's engine that's been out of production for decade?  Makes no sense....

Edited October 16, 2018 by Rob Hall

[Ace-Garageguy]

1 minute ago, Rob Hall said:

It's long out of production, it would probably not be cost-effective to get it to meet 2020 emission standards, and the tooling has probably been scrapped.   I think it's better for FCA to develop their own products than use someone else's castoffs... now if it were a current engine, they could probably make a business case for it or a JV of some sort. 

You may note in my first post RE: I said "if the tooling still exists".

Meeting emissions standards for a relatively recent engine design is primarily a matter of subtle tweaking of combustion chamber dynamics, valve event timing, and engine management peripherals and software.

[Ace-Garageguy]

9 minutes ago, Rob Hall said:

...Why would any company want to use some other company's engine that's been out of production for decade?  Makes no sense....

To you, perhaps.

Development cost of an entirely new engine design is heavily resource and capital-intensive.

Starting with a well-designed, proven platform that's a "modern" engine in every sense of the word could save a company tens if not hundreds of millions of dollars.

Jeep (AMC) bought in GM's odd-fire V6 eons ago...and eventually, GM bought it back...for pretty much the reasons I cited in both cases.

[Rob Hall]

8 minutes ago, Ace-Garageguy said:

 

Jeep (AMC) bought in GM's odd-fire V6 eons ago...and eventually, GM bought it back...for pretty much the reasons I cited in both cases.

Ancient history.  Not relevant.  And it hadn't been out of production for a decade...

Edited October 16, 2018 by Rob Hall

[Ace-Garageguy]

3 minutes ago, Rob Hall said:

Ancient history.  Not relevant.  And it hadn't been out of production for a decade...

Again, I'm curious.

If the tooling exists (as it well may), and if the engineering and design data are still available, what possible difference does a "decade" make?

Engine designs don't get crusty, rusty, and crumble, or get flat tires, or rot.

[Rob Hall]

If you think it’s such a great idea, write FCA a letter.  They will probably dismiss you as another crackpot.  

[Ace-Garageguy]

2 minutes ago, Rob Hall said:

If you think it’s such a great idea, write FCA a letter.  They will probably dismiss you as another crackpot.  

Thanks, Rob. That's the most convincing, well thought argument I've seen so far. Well done.  

[iamsuperdan]

I would love to see the old Jeep 4.0L inline 6 back in a new Jeep. I had a few Jeeps with that engine, and it was bulletproof. Had a 93 XJ Sport and put just over 440,000km on it before I sold it,. Then a 2005 Jeep TJ Sport that got about 80,000km in a year and a half. Tons of power and low end torque, decent economy, no issues. My next Jeep was a 2008 JK Sahara with the 3.8L V6, and it was so anemic. I loved the rest of the Jeep, but that engine was just awful.

 

Bill, you would probably know the answer to this. Was the 4.0L engine used in the 92 and later Jeeps based on that 4.2L GM engine that came from the AMC days? Or was it a brand new engine? I suppose I could google this, but I'd rather do it old school and ask someone.

 

 

 

[Rob Hall]

The Jeep 4.0 6 was an AMC design evolved from an engine dating to 1964 is my understanding.  No GM connection that I know of.    My ‘00 GC had the 4.0, was a good engine.   There was a 4.2l version in earlier Jeeps and and other AMC products. 

https://en.m.wikipedia.org/wiki/AMC_straight-6_engine#4.0

Now there were GM 4s and V6s in some Jeeps in the past, but no GM inline 6 that I’m aware of. 

Edited October 17, 2018 by Rob Hall

[Ace-Garageguy]

7 minutes ago, iamsuperdan said:

Bill, you would probably know the answer to this. Was the 4.0L engine used in the 92 and later Jeeps based on that 4.2L GM engine that came from the AMC days? Or was it a brand new engine? I suppose I could google this, but I'd rather do it old school and ask someone.

 I don't know. The only reason I'm somewhat knowledgeable about the recent 4.2 GM L6 is because I've looked at them extensively, first from the standpoint of swapping one into my old Jag XJ6 (and then after wondering why such a GOOD engine design was shelved early). The pre-1948-designed Jag engine is severely limited as far as delivering modern levels of streetable power due to its long stroke (though it was able to meet emissions standards through 1987 with electronic engine management and cam timing and compression ratio tinkering...and cats) but with polished cam covers and Webers it's gorgeous in a hot-rod, and can be scary-fast in a light car.

The GM 4.2 L6 makes close to a hundred HP more than the Jag in stock trim, is plenty torquey to drag a heavy car around...and it's much lighter than the massive cast-iron blocked Jag. As I've already done a 700R-4 gearbox swap to replace the old Borg-Warner 35 3-speed auto box, a modern engine that easily fits the engine bay is the next logical step in my Jag's development (I had a modular 4-cam Ford V8 slated to go in the hole, but it's a difficult swap, and the engine was stolen during a move). Owners of the 4.2 DOHC GM 6 are reporting over 200,000 miles of relatively trouble-free service too, with minimal maintenance. The big Jag engine needs religious care to stay in tune...not that I mind that in a sports car or a hot-rod, but in a big saloon I'd prefer to twist the key and go.

The trans swap made it an entirely different car, with the additional gear and lockup torque-converter working well with the engine's relatively low RPM torque curve, but an additional 100HP (without sacrificing idle quality) would make it go like a decades newer car...especially as the chassis and handling are on a par with (or better than) just about any large new vehicle.

Sorry for the digression. I know almost nothing about the 4.0 engine in the Jeep.  

[Rob Hall]

As far as the short lifespan of the GM Atlas 6, I assume it’s because of the demise of the Trailblazer and it’s GMT360 siblings.  The related Atlas 4 carried on a while longer in the Colorado and Canyon.   The Atlas 5 was short-lived also.

The inline 6 presumably was too long to fit in GM’s transverse engine FWD/AWD cars and CUVs, where V6s fit better. 

I assume they never offered it in the full size pickups since they already had a V6 available in them. 

Edited October 17, 2018 by Rob Hall

[Ace-Garageguy]

23 minutes ago, Rob Hall said:

As far as the short lifespan of the GM Atlas 6, I assume it’s because of the demise of the Trailblazer and it’s GMT360 siblings.  The related Atlas 4 carried on a while longer in the Colorado and Canyon.   The Atlas 5 was short-lived also.

The inline 6 presumably was too long to fit in GM’s transverse engine FWD/AWD cars and CUVs, where V6s fit better. 

You are absolutely correct.  

[1930fordpickup]

That 6 in the Jeep goes way back to Rambler. That is the start of it. 

The 6 in the Trailblazer is good but I am not sure they got good gas mileage.  They will last a lifetime just as all good 6's do. It would be a good choice Bill.