XJ engine swap feasability

[yossarian19]

Re: 3.5l engine swap feasability

I'm not advocating some sort of change to everyone's mindset here, but it is a little concerning that some of you haven't bothered to read, but simply offer an opinion.

The 3.5 has forged internals, free floating pistons, cross bolted 4 bolt mains and 4 valves per cylinder. I don't see how 250 hp is pushing it too hard. I've read a few threads on other boards about boost and tuning because it was stout.

I get that an LS swap is the flavor of the month or that I can avoid swapping a drivetrain with a stroker. Both of those come with their own host of problems, such as cooling an LS with a $600 radiator or working out the fuel management of a stroker. An LS swap also means a custom gauge package, hood and accessory clearance issues and most importantly, me breaking stuff with 350 hp under my foot.

I was hoping to engage in a technical discussion on how to make this work, rather than a discussion on why it wouldn't. Can the 3.5l talk to the jeep gauges? Is there a way to mate the 42RLE to the engine and make the computers talk together? Does the bellhousing even mount to it?

I understand the work involved. I don't need a lesson on an engine swap. I've ridden in an LJ with an auto and it drives just like my XJ with an auto. I guess the technical expertise of is limited to don't do it because no one has ever done it before.

I hear you and I did read your post.
I'm just not convinced it will be appreciably easier to put a Chryco 3.5 in an XJ than an LS. It may wind up cheaper, though, if only by a gauge set & a radiator. The $600 Novak isn't the only way to keep an LS cool, though.

Out of curiosity, what were you thinking as far as integrating the engine harnesses? General principles / best practices might be found by looking at (I know, I know) LS swap wiring guides, especially those concerning putting them in the GMT400 chassis as those trucks already have wiring harnesses for MPFI.

 

[Johnnie Walker]

Re: 3.5l engine swap feasability

Not too familar with this engine, but aren't these WIDE? If so, I can definitely see that as an issue that needs to be addressed.

 

[shortxjdoug]

3.5l engine swap feasability

I'm not advocating some sort of change to everyone's mindset here, but it is a little concerning that some of you haven't bothered to read, but simply offer an opinion.

The 3.5 has forged internals, free floating pistons, cross bolted 4 bolt mains and 4 valves per cylinder. I don't see how 250 hp is pushing it too hard. I've read a few threads on other boards about boost and tuning because it was stout.

I get that an LS swap is the flavor of the month or that I can avoid swapping a drivetrain with a stroker. Both of those come with their own host of problems, such as cooling an LS with a $600 radiator or working out the fuel management of a stroker. An LS swap also means a custom gauge package, hood and accessory clearance issues and most importantly, me breaking stuff with 350 hp under my foot.

I was hoping to engage in a technical discussion on how to make this work, rather than a discussion on why it wouldn't. Can the 3.5l talk to the jeep gauges? Is there a way to mate the 42RLE to the engine and make the computers talk together? Does the bellhousing even mount to it?

I understand the work involved. I don't need a lesson on an engine swap. I've ridden in an LJ with an auto and it drives just like my XJ with an auto. I guess the technical expertise of is limited to don't do it because no one has ever done it before.

What platform are you going into? An ob2 xj? Or your 96 bastard xj?

It doesnt matter particularly if the gauge package reads it at all. You're retaining the same speed sensor since youre using the 231 why not just leave the jeep harness in place. The only thing you need to figure out is tach signal, and the voodoo exists somewhere to make a 97+ cluster read a gm tach signal, surely it is just as possible for it to see tach signal from an engine of its own family. The ls2 jeep still has a full jeep harness and computer, with the check engine light wired to the gm pcm and the cluster is modified by redline performance to interpret gm tach signal.

The problem you may run into is the lack of tuning ability in the chrysler pcm. I know the hemis dont have as much play in the pcm as a chevy drivetrain and it seems to be a brand wide deal.

As far as the trans goes i dont see why the harness and tcm for the transverse unit wont run the rwd trans. That may be the only way it is possible depending on how much of the trans harness is integrated into the engine harness and how much engine sensor info it uses. You may be forced into using a later model donor since the libby and dak 42rle's have full electronic control along with some funky electronic torque converter clutch bs


.... And i dont even know if the bolt patterns on the 3.5 and 3.7 motors match, so this could all be moot either way


Btw that 3.5 makes peak hp at 6500 rpm, no thank you

 

[shortxjdoug]

3.5l engine swap feasability

http://www.turbododge.com/forums/f11/f68/152065-3-5l-manual-bellhousing.html

Take the 42rle and let nate use it as an anchor for his new boat.

If i read this correctly then the 3.3/3.5 and the wrangler 3.8 have the same bellhousing.

Sooooooo, run the jeep harness for gauges and body control, engine harness to run the motor, then stab a wrangler nsg370 6 speed behind it. If youre deadset on slushbox im sure i can find you a jk auto in tylers shop. Theyre all paying him tons of money to put ls motors in them. As long as you dont run into major flywheel issues it should be relatively straightforward. I think they have bellhousing mounted crank sensor triggers though too.


It can most likely be done....

 

[Root Moose]

Re: 3.5l engine swap feasability

And for the record my dream odd engine swap is a Lexus 1uz to an aw4..... Easier than you think.

My kind of odd-ball. 2UZ? 2UZ came mated to the A340... that's what is in the early 100 series.

I've seen people start this swap but never seen one completed - in an XJ.

 

[shortxjdoug]

3.5l engine swap feasability

My kind of odd-ball. 2UZ? 2UZ came mated to the A340... that's what is in the early 100 series.



I've seen people start this swap but never seen one completed - in an XJ.

They all came mated to an a340. The 2uz is an amazing motor for its size. The early pre vvt motors are in the 100 series cruisers and 1st gen tundras. Its as simple as building a frankentrans from the yota and jeep units

The attraction of a 1uz is a complete donor ls400 car can usually be had for under 800 bones. By the time you part it out and scrap you might break even

Sorry to hijack your thread with yota stuff josh

 

[RedHeep]

Re: 3.5l engine swap feasability

I think the discussion is healthy.

To answer a couple questions, I don't know. I don't know how the late 90's chrysler stuff will interface with my '96.

I don't know anything about a 1uz either. I'm not running out to rip the 4.0 out of my jeep, I'm brainstorming.

 

[shortxjdoug]

3.5l engine swap feasability

I think the discussion is healthy.

To answer a couple questions, I don't know. I don't know how the late 90's chrysler stuff will interface with my '96.

I don't know anything about a 1uz either. I'm not running out to rip the 4.0 out of my jeep, I'm brainstorming.

The 1uz motors are about the same power but i believe they make it a little bit lower in the power curve. I havent taken measurements to see how well it fits. Te biggest bonus to me is the use of the aw4. A 2uz brings .7 more liters displacement and almost 300 lbft of torque. Holy shit, 260hp and 300lbft of torque in an oddball engine swap that uses an aw4? Sign me up. Factory shifters, no modifying trans tunnel, and most importantly no chryco trans.

A 1uz has similar torque numbers to a jeep 4.0 but the 250 hp is a bonus as well as v8 noises. And both the 1uz and 2uz make their peak tq numbers at 3600 rpm. Your 4.0 makes its peak torque numbers around 3000 and a renix makes its peak torque numbers 2500.

Just brainstorming.


I think the 3.5 hasn't come forward as a hot swap because though its numbers look good on paper its more suited to street use, not for what we use them for. Its peak tq #s are at 4000rpm and even then its only 25lbft more than what your 4.0 makes at 1000 less rpm.

If it was going into your pile the gauge pack is fed by individual signals so it would be dirt simple. I wouldnt worry about having to build custom gauges for any motor in a pre 97 xj


Short"enjoys random motor swap discussion"xjdoug

 

[yossarian19]

Re: 3.5l engine swap feasability

Though it's got limited parts available for swaps, I really like the Atlas I6 for an XJ swap. 4.2 liter inline six, 290 HP / 275 TQ (though at higher engine speeds, like 4800 rpm for peak torque) and better fuel economy whenever you aren't using the HP.
A guy on here put a turbo Supra motor in his XJ, it was sick. That's another good option, though I don't think the naturally aspirated models have enough torque to be competitive with the 4.0 (I could also be totally wrong)

 

[altrocker1]

Re: 3.5l engine swap feasability

The manual swap makes this more interesting. Just a couple questions...

What are the dimensions of the motor? Like someone said width is always a concern in an xj chassis...

I would also be concerned about the peak power band being at 4k rpm. Are there superchargers that fit it? Something low boosted that would give it more low end grunt? The manual tranny certainly would help, but a little boost never hurts

 

[RedHeep]

Re: 3.5l engine swap feasability

I know we're all fixated on the high rpm peaks, but the torque curve is pretty respectable. it's over 200 ft lbs after 1400 rpm and stays that way through the peak at 4000 rpm. Chrysler propoganda:

What does a 4.0 dyno sheet look like?

 

[RedHeep]

Re: 3.5l engine swap feasability

The 99-01 models of the 300m are pcm/tcm and the 02-04 models are pcm only with integrated tcm. There are tuners available for those pcms.

 

[macgyvr]

3.5l engine swap feasability

Why so much 42rle hate?

mac 'owns one' gyvr

 

[shortxjdoug]

3.5l engine swap feasability

The 99-01 models of the 300m are pcm/tcm and the 02-04 models are pcm only with integrated tcm. There are tuners available for those pcms.

The problem with the whole deal is you're stuck using a jeep transmission. The 3.8 is the only chrysler motor with a rwd trans that matches the bellhousing. Google says the 3.7 in the liberty and the dakota shares its bellhousing pattern with the hemi and older chryco small blocks, not the 3.3 based family of v6s.


I would look for wiring diagrams or the pinouts for the transverse transmission vs pinouts for the jeep auto. See if they are similar and go from there. I think the jk trans control is all wrapped up in the pcm. It probably will have more in common with an 02-04 donor

Lots of guesses and maybes here

 

[Root Moose]

Re: 3.5l engine swap feasability

Were these engines ever offered with a manual transmission? Most ChryCo trannies have aftermarket controllers available... go that route to make the two units effectively stand alone.

Btw, the 1UZ and 2UZ, are they more or less the same dimensionally? Just curious.

 

[shortxjdoug]

Re: 3.5l engine swap feasability

Were these engines ever offered with a manual transmission? Most ChryCo trannies have aftermarket controllers available... go that route to make the two units effectively stand alone.

Btw, the 1UZ and 2UZ, are they more or less the same dimensionally? Just curious.

I don't think they were, though the nsg370 from the 3.8l wranglers will bolt to it.


As far as the dimensions on the yota v8s I'm not sure. I believe they are similar however they are pretty wide v8s to begin with.

 

[Hoooper]

Re: 3.5l engine swap feasability

I get that an LS swap is the flavor of the month or that I can avoid swapping a drivetrain with a stroker. Both of those come with their own host of problems, such as cooling an LS with a $600 radiator or working out the fuel management of a stroker. An LS swap also means a custom gauge package, hood and accessory clearance issues and most importantly, me breaking stuff with 350 hp under my foot.

I am running all my stock 96 gauges (except the tach, havent taken the time to set that up) from an LS. No hood clearance issues using the stock hood, accessory clearance is not a big issue and if youre concerned that you need to fab some brackets or buy a different accessory package that fits (yes there are many out there) then any engine swap is probably a bad idea for you. But youre right about the potential of breaking stuff, though I would say it doesnt make much sense to go through the effort of an engine swap for 75 HP and a couple lb ft.

 

[87manche]

Re: 3.5l engine swap feasability

boost+2uz seems interesting.

http://www.lexusv8.co.za/unusual-v8-lexus-projects/supra-2uz-twin-turbo-v8/

 

[bigdaddyjlove]

Re: 3.5l engine swap feasability

Just food for thought, but the Dodge Nitro had a 4.0 version of the Chrysler motor in it. It came witha 42re trans.

 

[RedHeep]

Re: 3.5l engine swap feasability

My original thought process was to stay in the late 90's production engines so the swap would be more plug and play. I don't know if that's the case or not, but that's what I was thinking.