TJ LS motor!

[Nellocore]

Has anyone gone down this road and put a LS motor in your TJ? I've been looking around and I've seen a few. I'd like to know the differences and pros and cons

 

[jps4jeep]

difference between an LS and what?

It's been done plenty of times, number of manufacturers making stand alone wiring harnesses for them. depending on the motor, they are a great power maker, some are fairly cheap to buy. recfently bought a 5.3 with less than 70K miles complete from intake to pan, with exhaust manifolds, wiring and ECM and paid $800. My standard is to rebuild any motor I swap in with un-known history, this motor is going into a light weight buggy and will not bother rebuilding.

I am holding out for a LS 6.0 LQ9, and if I come across one, I will be selling the 5.3.

 

[Nellocore]

The differences was between the LS and the normal wrangler 2.5 and 4.0. So If I were to drop an LS is my wrangler it's still street legal? And do you still use the computer or bypass it?

 

[jps4jeep]

OH ok, light years ahead of a 4.2, same reliability as a 4.0, about 130 hp more depending on what engine you use. I am only comparing the to the 5.3 LS block since it is the most readily available and easiest/cheapest to find.

the specs are

4.0 are 180 hp 235 ftlb (and depending on the year they are all a little different)

5.3 (LM7 truck motor) are 300 hp and 325 ftlb

if you can find the L33 5.3 from 05-07, it is an aluminum version of the LM7 and is good for about another 15 hp and 15 ftlb over the LM7. there was also a LM4 which was an aluminum block motor, but are hard to find in wrecking yards.

is it a legal swap, depends on your state and how you execute the swap. In my state (massachusetts) for me to swap to a LSX motor in a jeep, (this is the short list) the motor has to be same year or newer than the vehicle (a 99 motor into a 94 is fine, a 99 motor into a 04 is not legal) if the motor was originally equip with ODBI or II, it must be retained. All smog equipment on the new motor must be retained, can not go from EFI to Carb.


You should, and probably have to re-use the ECM. you can carb an LS motor, but not generally for street applications in a vehicle that was originally equip with EFI. But why go to a carb, you will loose so much of the advantage of the LS motor swap.

Painless, FAST are two manufacturers off the top of my head that make plug and play harnesses for LSX motors.

 

[Nellocore]

I really can't wait to swap I have an 04 wrangler. I was looking at parts list and stuff it looks like I have some saving up to do and your helping me alot!

 

[Nellocore]

Is the motor you found for 800 the LS1 aluminum block?

 

[jps4jeep]

No it's a 5.3 LM7 from an 06 gmc 1500

the LS1 is a 5.7 motor. if you want an aluminum block, look for the LM4 or L33 from the trucks. the LS1 carry's a higher price becauswe everyone and their brother has heard of an LS1. The LS1 was used in the Corvette and in F-Body from 97-04 rated at 305HP - 325HP and 250 ftlb. The fact being, some if not most of the truck motors from a more current platform make the same (or more) power, more torque, and will have 4 bolt mains as opposed to 2 bolt mains. the aftermarket has addressed these motors and parts are cheaper than an LS1.

 

[jps4jeep]

oh, to do a 50 state legal swap, your looking at about $5000-6000 which includes the motor and trans, harness and all the misc. parts assuming you do it properly, don't hack anything together because in the end, you'll just have a hacked together POS.

 

[Nellocore]

My dads been a mechanic his whole life he will more then likely be helping me the whole way through. He has rebuilt a 454 and alot of 350s so hopefully he can help out. The price range is kinda what I expected in your honest opinion is it worth it? I always wanted to give my jeep alil more power and I figured go big or go home and replace the motor.

 

[jps4jeep]

if you have that much money that is disposably income, then it's worth it. I would replace the motor in my YJ, but it runs so well so I see no need to replace it. when it does die, I will probably go with either a 5.3 or a 6.0 and Auto, but I will be doing it out of necessity.