Jeep Inline 6 Engine to Debut in April

[Stratus109]

Inline 6 engines are the bomb. I have a 4.0 in the garage with 230k on it still going strong. I welcome a torquey i6 with open arms.

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[The Bean]

The investment group that owns Jeep, Ram, Chrysler, Dodge and several more auto brands (several European brands).

Stellantis isn’t an investment group. Stellantis is the new name for FCA after it was merged with PSA (although it was written that FCA acquired PSA, because FCA had more equity and would create a stronger intial evaluation), which owns Peugeot, Citroen, and DS. The Stellantis name only exists on the corporate marketing level though; so for NA cars you’ll still see the FCA US LLC branding.

 

[Iamstubb]

The USN loved their radials.

A friend of my dad's has several huge radials. I know airplanes but know nearly nothing about radials. Photos from a visit to my dad's friends about 15 years ago.

Best sounding engine, period. I love them radials.

 

[ShadowsPapa]

The Jeep 4.0 liter is legendary, but Chrysler couldn't squeeze the necessary MPGs from it for CAFE.

It was a mid-1980s design which went through a large number of changes to resolve NVH. In about 95 the blocks were even marked NVH. MOPAR added ribs to the left side to stiffen the block, a stud girdle was added to stiffen the lower end, a cam retainer plate was added about 99 I think to replace the spring and button to keep the cam back. I can't recall when they moved to a damper on the timing chain to quiet it (double roller).
It was long in tooth. I'm not so sure it didn't keep living in Chinese built vehicles for a bit longer.
Some say it was also scrapped due to the age of the tooling, etc............. ?

 

[CMac]

Don't worry guys: Stellantis will see to it that it'll be de-rated to about 284hp and 290 ft-lbs of torque. It'll be advertised to get 23 mpg... but in reality will get about 14. ???

Still... I'd seriously consider the upgrade.

 

[Wolf Island Diver]

My immediate (and mostly pointless) thoughts after not bothering to read anything on this new engine.

1. But, but, but…. I seem to remember the 4.0 being too long for front impact standards, so the JK got a garbage minivan engine that ran on the crushed souls of TJ enthusiasts.

2. I hope it’s not a bimmer engine with a bunch of plastic doohickeys inside the block that break after 20k miles, ruining the engine, but are considered “maintenance items” by zee Germans.

3. I hope it’s not made by Stellantis or Motori (just kidding, I love my little diesel boat motor)

4. I hope they’ve learned to clean casting sand out of the engine blocks and design heads right the first time around.

5. I hope it’s some kind of freakish b@$t@rd of the Datsun KA-24E and the AMC 4.0 and drives and sounds like a tractor.

6. I hope they make they make a diesel version! (macaroni with the chicken strips….uhhhh!)

 

[Labswine]

It was a mid-1980s design which went through a large number of changes to resolve NVH.

Some say it was also scrapped due to the age of the tooling, etc............. ?

If I recall, one of the main reasons that Jeep dumped the 4.0L I-6 was that they couldn't get any more MPGs out of it with current technology at the time. I call BS on that because with my '96 GC Laredo with the 4.0L, when I got it it, it was getting like 15 mpg running around and maybe 19 mpg on the highway.

Simple mods were multi point fuel injectors (Bosch FMS 22#/hr from the Mustang 5.0L) where the originals were Bosch single point 19 #/hr so better fuel atomization, opened up the intake for better breathing plus the venerable K&N air filter, changed the exhaust for less restriction like mandrel bent tubing, a more free flowing cat and muffler (the cat went bad anyways so it was replaced with a free flow one)...hot-rodding 101, better breathing better power, ergo, better HP/lb ratio meant the engine didn't have to work so hard to do the same job.

After these mods, I was averaging 19 mpg running around, an average of 23 mpg highway (with traffic as well, going back and forth across Connecticut on I-95) and saw a best of 25.5 mpg on a trip to Florida from Massachusetts and back, averaged 24+ mpg that trip. Plus, it had over 175K miles on it by that point!!! That engine had over 240K miles on it when I donated the car to charity because of electrical issues, not mechanical issues.

So, if they truly wanted to get better fuel economy out of that engine, they should have make easy modifications that would have allowed that.

 

[Caraholic]

I remember the old 4.0 was unable to meet new standards and the investment needed to keep the old tooling was prohibitive. They knew in 2001 that it was gonna die by 2006 MY if I recall rightly

 

[ShadowsPapa]

I get 20s to mid 20s in summer, 17-18 combined driving in winter although I now park my car in winter. A few tweaks and it's not that hard to do. And that's a fairly heavy car - 3,200-3,300 pounds.
Mine is a 94 and I know the later ones did a bit better with better intake design and so on.
Finding those injectors is a chore - I bought some "cleaned and tested" Bosch injectors for mine and it's actually made things worse than the stock injectors which has 130,000 miles on them!

 

[ShadowsPapa]

I remember the old 4.0 was unable to meet new standards and the investment needed to keep the old tooling was prohibitive. They knew in 2001 that it was gonna die by 2006 MY if I recall rightly

The AMC people who moved forward after 1988 (to MOPAR) also said the tooling and molds were going south and the equipment was too expensive to keep up. Some of that had been around since 1985 as the first 4.0 was 1986 model year if I recall correctly. My first 4.0 was an 87 Comanche which I used as a farm truck.

 

[NachoRuby]

If I recall, one of the main reasons that Jeep dumped the 4.0L I-6 was that they couldn't get any more MPGs out of it with current technology at the time. I call BS on that because with my '96 GC Laredo with the 4.0L, when I got it it, it was getting like 15 mpg running around and maybe 19 mpg on the highway.

Simple mods were multi point fuel injectors (Bosch FMS 22#/hr from the Mustang 5.0L) where the originals were Bosch single point 19 #/hr so better fuel atomization, opened up the intake for better breathing plus the venerable K&N air filter, changed the exhaust for less restriction like mandrel bent tubing, a more free flowing cat and muffler (the cat went bad anyways so it was replaced with a free flow one)...hot-rodding 101, better breathing better power, ergo, better HP/lb ratio meant the engine didn't have to work so hard to do the same job.

After these mods, I was averaging 19 mpg running around, an average of 23 mpg highway (with traffic as well, going back and forth across Connecticut on I-95) and saw a best of 25.5 mpg on a trip to Florida from Massachusetts and back, averaged 24+ mpg that trip. Plus, it had over 175K miles on it by that point!!! That engine had over 240K miles on it when I donated the car to charity because of electrical issues, not mechanical issues.

So, if they truly wanted to get better fuel economy out of that engine, they should have make easy modifications that would have allowed that.

My TJ Wrangler 4.0 sport got maybe 17mpg, at best. And that was a 2 door vehicle with no air conditioning. But it also suffered from our familiar brick like aerodynamics.

 

[Wolf Island Diver]

My understanding was that the 4.0 was made by dwarves and when middle earth was forgotten the knowledge to craft such fine pieces of machinery was lost. Although apparently Sauron survived which explains the Nissan CrossCabriolet and the new trend of having to control air vent direction via touch screen.

 

[RichDSport]

I hope this is an advancement in power and fuel economy and not just a nostalgia play for Stellantis. Everyone who owned an XJ loved the 4.0 Litre engine. It was a total blast to drive with the manual transmission. I owned an RX-8 for a couple of years, and it was fun to drive but got horrible fuel economy. There’s a reason why the rotary isn’t being used anymore, and I wonder about the economy of an inline six. Even BMW is moving away from them, which is kind of too bad.

 

[ShadowsPapa]

My TJ Wrangler 4.0 sport got maybe 17mpg, at best. And that was a 2 door vehicle with no air conditioning. But it also suffered from our familiar brick like aerodynamics.

20 points from Gryffindor for the use of the term "aerodynamics" in the same paragraph as Jeep Wrangler.

 

[Klutch]

The AMC people who moved forward after 1988 (to MOPAR) also said the tooling and molds were going south and the equipment was too expensive to keep up. Some of that had been around since 1985 as the first 4.0 was 1986 model year if I recall correctly. My first 4.0 was an 87 Comanche which I used as a farm truck.

The 4.0 wasn't available until 87. I owned a 1986 Comanche for 21 years. (Sold it when I bought my JT.) That Comanche had the "upgrade" engine which was a Chevrolet 2.8 Liter V6. Jeez did that engine suck. And yes, my Comanche came from the factory with a Chevrolet Engine, Chevrolet transmission and a Chevrolet S10 interior. That's how AMC rolled back then.

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