Modern/Current XJ Replacement?

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Feb 10, 2013 | 05:05 PM

#46

motorcharge

CF Veteran

Joined: Mar 2012

Posts: 1,369

Likes: 0

From: Richmond, VA

Model: Cherokee

Quote:

Originally Posted by BimmerJeeper

Is the crappy 0331 head from the 2000-01 XJ's also used on all the post-01 Jeep Liberty models?

No. Liberty's never had the 4.0 and the 0331 problem was exclusive to the XJ.

Quote:

Originally Posted by BimmerJeeper

Thanks for the clarifications.
I definitely can feel the low end torque in my 1998 4.0L i6.

Salad, are you sure the old 1990s engines are called PowerTech? Everyone on these forums only says that the 1990's "Powertech" XJ engines are bulletproof. Goes to 300k and has torque, as you said. Why did the earlier poster say these "PowerTech" engines are bad? Or did he just mean the NEW post-2001 "PowerTech" engines are not as good? This says Powertech is post-2002, which would make sense.

Powertech motors didn't come to be til the mid-2000s. The first was a v8 in Grand Cherokees, then a 3.7l v6 for the Libertys. There was a 4.0 i6 powertech based on the AMC 4.0 in WJ Grand Cherokees that people sometimes refer to.

Quote:

Originally Posted by BimmerJeeper

I don't know much about IFS, but it seems like it would make for better off-roading. Each wheel can do its own thing. Isn't that what all those "parked on a curb" photos are trying to convey? One wheel is totally out of whack with the rest of the Jeep. I'd think IFS is what this is all about.

It's better for certain situations, rock crawling isn't one of them. It's definitely better in low center of gravity off road vehicles like trophy trucks, sand rails, and most off road racing. If I were going to do Jeepspeed racing I'd seriously look at swapping out both axles for both IFS and IRS.

You don't want IFS with a straight rear axle on trails, rocks, ect because it really throws center of gravity out of wack and makes for really odd balancing act situations. It's also easier to get hung up on stuff and you can't lock differentials on IFS like you can on a solid axle afaik.

Feb 10, 2013 | 05:39 PM

#47

belvedere

CF Veteran

Joined: Jul 2012

Posts: 1,395

Likes: 1

From: SD

Year: 1998

Model: Cherokee

Engine: 4.0

Quote:

Originally Posted by salad

In terms of direct replacement though, in 2002 Chrysler put their 3.7L V6 into the KJ platorm. Reliability issues aside, as far as I've managed to tell it gets about the same fuel economy as the I6 and puts out less power. One of the hallmarks of the 4.0L I6 is low-end torque for doing grunt work. Despite improvements to overall power output the 3.7L lacks that torque at lower RPM that wheelers seek. All of its power is made above 4000 RPM

Being used in Dodge Caravans as well it was quickly deemed "gutless minivan POS"

The 3.7 was never used in any minivan.

Feb 10, 2013 | 07:34 PM

#48

Bob98Classic

Member

Joined: Dec 2012

Posts: 200

Likes: 2

Model: Cherokee

Correct, 3.7 was not in the mini van, but the 3.6 at 283hp/6 speed trans,would be a killer...

Feb 10, 2013 | 09:44 PM

#49

salad

Herp Derp Jerp

Joined: Nov 2011

Posts: 18,251

Likes: 17

From: Parham, ON

Year: 1999

Model: Cherokee

Engine: 4.0L OBD-II

Quote:

Originally Posted by BimmerJeeper

Salad, are you sure the old 1990s engines are called PowerTech? Everyone on these forums only says that the 1990's "Powertech" XJ engines are bulletproof. Goes to 300k and has torque, as you said. Why did the earlier poster say these "PowerTech" engines are bad? Or did he just mean the NEW post-2001 "PowerTech" engines are not as good? This says Powertech is post-2002, which would make sense. http://en.wikipedia.org/wiki/Chrysler_PowerTech_engine

From that page:

"Chrysler also used the "PowerTech" name on other engines used in Jeep vehicles, including some later units of the 2.5 L I4 and 4.0 L I6 designs inherited from AMC after buying that company out in 1987, and the 2.4 L Neon four-cylinder engine."

If you look at the Chrysler marketing stuff, PowerTech and High Output were often used synonymously. When they dropped the HO designation for the 4.0s, only the PowerTech branding remained. If you check your build sheet you should see a line item for "4.0L I6 Power Tech Engine". You'll also find the same nomenclature in the FSMs.

Interesting read about the 4.0L: http://www.allpar.com/mopar/40.html

Quote:

Originally Posted by belvedere

The 3.7 was never used in any minivan.

Whoops you are correct. I was thinking of the 3.8L and JKs, not 3.7L and KJs

Feb 11, 2013 | 03:16 PM

#50

Kevin108

Member

Joined: Jun 2009

Posts: 194

Likes: 0

From: Portsmouth, VA

Year: 2000

Model: Cherokee

Engine: 4.0

Quote:

Originally Posted by BimmerJeeper

Is the crappy 0331 head from the 2000-01 XJ's also used on all the post-01 Jeep Liberty models?

No but the TJ/WJs did have heads that worked for swaps. They were labeled TUPY.

Feb 11, 2013 | 10:11 PM

#51

Kevin108

Member

Joined: Jun 2009

Posts: 194

Likes: 0

From: Portsmouth, VA

Year: 2000

Model: Cherokee

Engine: 4.0

Quote:

Originally Posted by motorcharge

lol no they're not. The 4 door JK has a bigger wheelbase than the XJ and is really similar in size, but slightly wider. It's also got more stock ground clearance than an XJ does.

I have an 85 Ramcharger and it's nowhere near as small as a 4 door JK is. Hell the interior of a 4 door JK has less room than my XJ does.

Vehicle____Wheelbase__Length__Height__Width
XJ_________101.4"_____167.5"__64.0"___69.4"
JK 4-Door__116.0"_____173.4"__70.9"___73.9"
Bronco_____104.7"_____183.6"__74.4"___79.1"
Ramcharger 106.0"_____184.6"__73.1"___79.5"
K5 Blazer__106.5"_____184.8"__73.8"___79.6"

A JK is roughly 6" wider, longer and taller than an XJ with 15" more wheelbase but only 6" narrower, 10" shorter and 4" lower than a full-size. I also learned an XJ is only 3" wider than a Corolla.