Jeep LS swap for the LJ

glockman

I hate Jeep trucks
Location
Pleasant Grove
I've been thinking and researching this for way, way to long. Apparently so long that my coworker was tired of listening to "someday" plans and found me a good deal on a motor.

What I'm starting with
2006 LJ Rubicon with 107K miles on the stock 4.0 and craptastic Auto trans.
It's currently on the stock Rubi 44's and I'm running 37's with 4.88 gears. RCV front and Chromo rears.

Parts I plan to use in the swap
5.3 from a 2004 Suburban with F-body C6 Corvette oil pan, F body Exhaust manifolds and truck intake.
4L60E -I can't imagine it will fail if the 42RLE lived this long.
Chevy manual shifted NP241 with JB SYE kit.
150 tunes new harness and PCM tuning. - Harness done by me.
PCM Tuned by-

I'll keep the stock jeep dash, PCM and gauges.
Tach will be addressed with a Jeep speed 32 tooth crank tone ring or a Novak emulator.
Oil pressure gauge will be jeep sensor located in the oil filter/cooler housing.
Coolant temp will be 98 camaro 3 wire unit sending to the GM PCM and the Jeep dash.

Daves Unlimited motor mounts.
Daves unlimited high mount A/C bracket York compressor mount, not retaining A/C
Superior radiator with shroud and spall electric fan.
B&M front mount trans cooler is already mounted prolonging my 42RLE suffering.
Camaro shifter in the stock jeep console - If I can't make that work, I'll probably do a Lokar. Jeep shifter with Novak adapter and bracket
Not sure on T-case shifter. - Novak cable shifter
Not sure on drive line mods required.- Used Gaylons. He did a Ford Bronco rear flange to mate the 1310 CV on my Rubicon shaft to the 1350 Ford flange in the JB conversions SYE.
The front output on the NP241C has a flange. They installed a dodge flange to my jeep shaft to mate to the flange on the T case.

For exhaust I would like to run the crossover below the bell housing vs around the front of the oil pan. I also want to run one cat and a 3" single exhaust to exit in the stock location.

This is a pretty huge undertaking for me. I don't think I will ever sell the LJ and I have hated the trans and under powered 4.0 since we bought it. I think this will solve all those issues and I hope to keep it as stock looking/functioning and reliable as possible so I can enjoy it for many years. That means I'll have to fight my urge to get things done quickly to keep the quality of work at a level I won't regret later. Do it once and do it right.

I pick the engine up tomorrow and will start collecting parts. I am a decent wrench but this is my first LS swap so anyone with any experience, please point out issues you see with my plan. I'm open and grateful for any and all advice.
 
Last edited:

I Lean

Mbryson's hairdresser
Vendor
Location
Utah
I love the direction. :D

One question though--I was under the impression you need to install an engine that is the same year, or newer than the vehicle it's going in. Is that not still the requirement for emissions checks?
 

glockman

I hate Jeep trucks
Location
Pleasant Grove
From all the info I read for Ut county, it has to be the same family of engine. Since the LS in 05 was the exact same as in 06 this should fulfill the requirement. The code is somewhat vague also. Several people I talked to said as long as it passed the emissions values for the 06 jeep they didn't care what engine it was.
 

UNSTUCK

But stuck more often.
Very jealous of this build. There’s something magical to me about an LJ with an LS.
A few random thoughts:

-if you can’t thin down the stock harness on your own, speartech is with every penny. It’s a brand new harness built to your specs. Everything just fits as you want it.
-150 tunes will do the basic thin out of your harness. This means some wires will be too short and most will be way too long. I’m ocd about wiring and was not pleased with what they sent me. I redid most of that harness for the commando I built. I just do all my own wiring now anyways. That way I can only blame myself. A Novak harness I used was pinned wrong in a few places in a tj I built. That’s was a fight.
-150 tunes will give you a basic tune on the pcm. Turning off that vats is most important. I have a local guy in Lehi that tunes my stuff. He’ll do a ride along afterwards and play with trans shift points and pressures. I think i paid about $250 last time for his service.
-I think I have all/most of the Novak parts to keep your dash in place. I can dig for them if you want them.

Good luck! There’s a few guys that have done these swaps and know their way around them pretty well on here. It’s not nearly as bad as you might be thinking it will be.
 

Greg

Make RME Rockcrawling Again!
Admin
I love the plan! Sounds like you have all the details worked out. Making the factory gauges work with the 5.3 will be so nice. IMO the 5.3 has a totally opposite powerband than a 4.0.... the 4.0 is great for low end power and the 5.3 LOVES higher RPM's, but still has enough grunt down low to cruise around. The gear ratios of the 4L60E will favor the V8, especially the low 1st gear and deep OD ratio. You'll be real happy with the 4.88's and 5.3!

How many miles are on the 5.3? If it's 100k or more, I'd suggest a quick refresh of a few items and an upgrade or 2. I'd replace & upgrade the oil pump (high volume), replace the water pump and highly recommend an aftermarket cam with a double roller timing chain. It might be worth having the heads gone thru, replace the valve seals (so you don't have any problems burning oil sooner rather than later) and upgrade the valve springs, if you do upgrade the cam.

The factory cams are weak, you'll see some pretty significant gains with an aftermarket cam without effecting driveability. The 5.3 I swapped into my TJ was completely stock and while it moved the Jeep pretty well, it could have been a lot better with a aftermarket cam. I did regret keeping it stock, once it was all done.
 

Pile of parts

Well-Known Member
Location
South Jordan
From all the info I read for Ut county, it has to be the same family of engine. Since the LS in 05 was the exact same as in 06 this should fulfill the requirement. The code is somewhat vague also. Several people I talked to said as long as it passed the emissions values for the 06 jeep they didn't care what engine it was.
This is what I have understood as well. Not necessarily same year or newer as long as it meets the requirements of the vehicle receiving the donor.
 

glockman

I hate Jeep trucks
Location
Pleasant Grove
Very jealous of this build. There’s something magical to me about an LJ with an LS.
A few random thoughts:

-if you can’t thin down the stock harness on your own, speartech is with every penny. It’s a brand new harness built to your specs. Everything just fits as you want it.
-150 tunes will do the basic thin out of your harness. This means some wires will be too short and most will be way too long. I’m ocd about wiring and was not pleased with what they sent me. I redid most of that harness for the commando I built. I just do all my own wiring now anyways. That way I can only blame myself. A Novak harness I used was pinned wrong in a few places in a tj I built. That’s was a fight.
-150 tunes will give you a basic tune on the pcm. Turning off that vats is most important. I have a local guy in Lehi that tunes my stuff. He’ll do a ride along afterwards and play with trans shift points and pressures. I think i paid about $250 last time for his service.
-I think I have all/most of the Novak parts to keep your dash in place. I can dig for them if you want them.
Great info, thank you. I may try doing my own harness. I'm an electronic tech by trade and lt1swap.com has pretty detailed instructions. If not, it's good to know speartech is the way to go. I kind of thought that, but I think I needed confirmation.
I'll take the Novak parts if you have them and the number for your tuner in Lehi. That would be way better than sending the pcm off.
 

glockman

I hate Jeep trucks
Location
Pleasant Grove
How many miles are on the 5.3?
It's got 130ish I think. I planned on having Cleggs go over the heads. I'll look at a water and oil pump. I'm trying to balance replacing stuff that makes sense without letting project creep drain my budget and time. I will likely do a cam but not initially. That is one place I won't have to buy twice if I upgrade later.
Ive been reading and rereading the pirate 5.3 tj thread (all 240 pages) and it's cool to see your old tj mentioned. Thanks for the F body oil pan part#s :D
 
Last edited:

glockman

I hate Jeep trucks
Location
Pleasant Grove
But also want to thank you for doing a build thread on it. Document the crap out of everything, please :D.

- DAA

I plan to. I'll try and keep a running total too so everyone can get an idea of the cost. I hope to have the thing back on the road for around $4k before selling my old drive train. If I get the big $$$$ for my 241OR that number will decrease significantly. People seem to think those things have Toyota stamped on them somewhere.
 

bryson

RME Resident Ninja
Supporting Member
Location
West Jordan
I think it's tight to squeeze the mechanical fan in and I don't know if they pull enough air.
Fit is one thing to contend with for sure, but most electric fans won't pull anywhere near what a mechanical fan will.

If you do stay with electric there are many proven solutions for your application though, so you shouldn't have an issue.
 

Black Label

Owner Black Label Design
Location
Northern Utah
I’ve been in your shoes. The LJ is such an amazing Jeep and works so well with the LS.
This is mine... not going to hi jack your build but if to have any questions fell free to ask.
2006 LJR
2004 5.3L 4L60E with the OR tcase going to be a 6.0L in a few months.

Jeep has 52K on it and the engine has less then 40K rebuilt transmission did all the work myself, wiring install everything, with a buddy and used some Novak parts. Sent the gauge to redline to have them work it over. Best idea.

Only thing I hate is the air filter, which I’ll address when I do the 6.0L

7D159C07-420A-471A-A295-BC09E318EBD2.jpeg7EEE923A-29E8-4217-8531-21DD7D6DFBE9.jpeg4211E5B6-3C1B-48BA-B649-7E9A79DE9D84.jpeg
 

glockman

I hate Jeep trucks
Location
Pleasant Grove
I’ve been in your shoes. The LJ is such an amazing Jeep and works so well with the LS.
This is mine... not going to hi jack your build but if to have any questions fell free to ask.
2006 LJR
2004 5.3L 4L60E with the OR tcase going to be a 6.0L in a few months.

Jeep has 52K on it and the engine has less then 40K rebuilt transmission did all the work myself, wiring install everything, with a buddy and used some Novak parts. Sent the gauge to redline to have them work it over. Best idea.

Only thing I hate is the air filter, which I’ll address when I do the 6.0L
That looks great.
Did redline just rework your tach? What made you go that route vs the emulator? I've heard people have success with both.

What radiator/fan are you using?
What shifter are you using?
 

DaveB

Long Jeep Fan
Location
Holladay, Utah
I'm in the middle of an LS 5.3/4L60E swap in my Scrambler. I used the Dave's Custom motor mounts (got to love the name) which allowed me to center the motor in the narrow CJ frame. I have about 1.5" of clearance between the radiator and the mechanical fan. I'm not sure if a CJ engine bay has more space than the LJ however. The swap I'm in the middle of now is going to a driver's side drop front axle so that the driveline clearance to the tranny pan and the power steering pump to the steering shaft is better. The messy thing that still lies ahead is the exhaust routing, its going to be a tight fit.
 

Bart

Registered User
Location
Arm Utah
Love the direction and following this thread closely. Same plans that I have for my 07 JKUR. Very interested in the Utah County emissions stuff.
 
Top