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Discussion Starter #1
I’m given to understand there are some differences between the 3.6 engines between the jl and jk’s.

Does anyone know about some of these differences? How about a good source for information? I can’t seem to find any information out there.
 

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The biggest one I've heard of, maybe the only one, is the stop/start thing with the engine... where it stops the engine when you stop, and automatically restarts when you put your foot on the gas.

I wouldn't like it, but you can turn that feature off with a button on the dash. The problem is that you can't permanently turn it off on a menu somewhere. You have to push the disable button every time you start it up... assuming you don't like it, that is.

I don't own a JL. That's just regurgitated from what I've read.

As far as I know, that's the only significant change. Same basic engine.
 

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Discussion Starter #6
Crap. According to those articles the aussies had a 3.6 in their 2010 jk’s!

My 2010 jk had that 3.8! Crap again.

Well, temper tantrum over that still doesn’t indicate any differences between the engines in the jk and jl. Of course there may not be any. I’ve just run across a couple of references to such.

I’ll just keep looking.

Very good article btw.
 

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Crap. According to those articles the aussies had a 3.6 in their 2010 jk’s!

My 2010 jk had that 3.8! Crap again.

Well, temper tantrum over that still doesn’t indicate any differences between the engines in the jk and jl. Of course there may not be any. I’ve just run across a couple of references to such.

I’ll just keep looking.

Very good article btw.
Its in the article, a lot of differences:
Cooled EGR valve
New valve train
New PCV
Smaller oil sump
Higher compression
ESS
JL Pentastar is a more complicated version with the same power output.
 

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Discussion Starter #8
Its in the article, a lot of differences:
Cooled EGR valve
New valve train
New PCV
Smaller oil sump
Higher compression
ESS
JL Pentastar is a more complicated version with the same power output.
Those articles (I followed the links) showed the differences between the 2010 3.6 and the 2016 3.6. I’m grateful. I didn’t even know about the 2010 model, that’s what’s in my 2015.

However it doesn’t tell me the differences between the 2016 3.6 and the version in the jl.

Again. Thanks. At least I know more than I did.
 

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Those articles (I followed the links) showed the differences between the 2010 3.6 and the 2016 3.6. I’m grateful. I didn’t even know about the 2010 model, that’s what’s in my 2015.

However it doesn’t tell me the differences between the 2016 3.6 and the version in the jl.

Again. Thanks. At least I know more than I did.
There are only two versions of Pentastar in this specific article "2010" is JK version and "2016" is JL version.
Since its Australian market it could be that they go by calendar year and not by "model tear" like in US, anyway its the same engine.
 

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Thanks but that doesn’t tell me the differences, if any, between those engines for the jk as opposed to the jl’s.
It does under the "Pentastar Upgrade" section. The engine was updated in 16 but the updated version didn't make its way into Wranglers until the JLs were released.

For 2016, FCA released an updated version of the 3.6 L engine for the Jeep Grand Cherokee and Dodge Durango. This engine now featured two-stage variable valve lift (VVL), a cooled EGR, a new intake manifold, new fuel injectors, and new ignition coils. It also features upgrades to the variable valve timing (VVT) system, an increased compression ratio (11.3:1), lower internal friction and lower weight. These improvements help to increase power as well as efficiency.[10] The new version, however, has lost its flex-fuel capability.
 

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Discussion Starter #12
There are only two versions of Pentastar in this specific article "2010" is JK version and "2016" is JL version.
Since its Australian market it could be that they go by calendar year and not by "model tear" like in US, anyway its the same engine.
Ok. Thanks. I’m not an engineer but from what I read the jl version is better if only because it’s lighter and uses fewer parts........right?
 

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Discussion Starter #13
It does under the "Pentastar Upgrade" section. The engine was updated in 16 but the updated version didn't make its way into Wranglers until the JLs were released.

For 2016, FCA released an updated version of the 3.6 L engine for the Jeep Grand Cherokee and Dodge Durango. This engine now featured two-stage variable valve lift (VVL), a cooled EGR, a new intake manifold, new fuel injectors, and new ignition coils. It also features upgrades to the variable valve timing (VVT) system, an increased compression ratio (11.3:1), lower internal friction and lower weight. These improvements help to increase power as well as efficiency.[10] The new version, however, has lost its flex-fuel capability.
Thanks for pointing that out.
 

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Discussion Starter #14
Its in the article, a lot of differences:
Cooled EGR valve
New valve train
New PCV
Smaller oil sump
Higher compression
ESS
JL Pentastar is a more complicated version with the same power output.
But lighter and with fewer parts. I’m guessing a better engine overall.
 

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Ok. Thanks. I’m not an engineer but from what I read the jl version is better if only because it’s lighter and uses fewer parts........right?
Better emissions control and possibly better gas mileage were probably the motivations behind the change.
 

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But lighter and with fewer parts. I’m guessing a better engine overall.
On paper yes,
In reality they shaved metal from everywhere including crankshaft:
Crankshaft journal width: 68 mm (previously 72 mm); and,
Crank pin width: 54 mm (previously 59 mm).
Im not an engineer but 1/5 inch smaller crankshaft pins/journals doesn't look like they made it stronger.
Only time will show is it better or not.
 

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On paper yes,
In reality they shaved metal from everywhere including crankshaft:
Crankshaft journal width: 68 mm (previously 72 mm); and,
Crank pin width: 54 mm (previously 59 mm).
Im not an engineer but 1/5 inch smaller crankshaft pins/journals doesn't look like they made it stronger.
Only time will show is it better or not.
Yeah not enough information to say really. Less rotating mass (and less friction) is usually a good thing, but depending on if they adjusted the rod and main bearing clearances and/or made the bearings more robust only time will tell. With the tools available today like CFD and FEA and FEMA, everything is designed (and frankly a good deal of the "testing") via simulations on a computer. This has lead to many benefits obviously, but it's mostly theoretical and a best-case-scenario kind of thing. The real data comes via customers beating on their junk and the feedback from the dealer network. Then they can see where the all of the computer data fell short, and changes/improvements can be made. But only after many miserable owners have had to deal with the failures. Que sera, sera as they say.
 

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So were the changes made to have a better product for the consumer or to help the bottom line of FCA? Given the track record of FCA.
 
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Discussion Starter #20
On paper yes,
In reality they shaved metal from everywhere including crankshaft:
Crankshaft journal width: 68 mm (previously 72 mm); and,
Crank pin width: 54 mm (previously 59 mm).
Im not an engineer but 1/5 inch smaller crankshaft pins/journals doesn't look like they made it stronger.
Only time will show is it better or not.
Yeah. Time will tell.
 
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