Direct fit -- upgrading a 2004 (Gen 3) 5.3L LS to a Gen 5 2019 5.3L?

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Laredo Matt
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Direct fit -- upgrading a 2004 (Gen 3) 5.3L LS to a Gen 5 2019 5.3L?

Post by Laredo Matt »

Has anyone upgrade a older (Gen 3) LS 5.3 to a modern (Gen 5 2019 and new) 5.3L?

Since the jeep is stripped to frame I thought now would be the time to replace the older LS a PO had swapped. No history on it and rebuilding for more power isn't really a route I want to go for a multitude of reasons.

I've tried to compare block specs for Gen 3 (old engine) to the new a Gen 5 but not really finding exactly what I need. Size wise, they are pretty close in overall dimensions and I'm sure there is more than enough room in the engine but. Ideally, I'm hoping it is a direct bolt in so I won't have to relocate engine mounts etc. AND there won't be an issues with firewall. I haven't been able to find any block specific measurements to see if the blocks are same size or have changed.

I know this is probably pretty specific cased and question and there is a good chance no-one can answer but if you have an tech websites or jeep shops you think might be able to could help I'd appreciate it any references.

thanks!
Matt
83 Cherokee Laredo WT
L8T 6.6L, 6L90
GEN III LS Swap (LM7 block)
4L60E
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Stuka
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Re: Direct fit -- upgrading a 2004 (Gen 3) 5.3L LS to a Gen 5 2019 5.3L?

Post by Stuka »

You will need a new standalone controller. Your gen3 ECU won't work with the gen5. Tuning them is also quite different.

You will also need to look into your fuel system as gen5's are direct injected.

As far as engine mounts, you will most likely need a different "mount", but I would think the frame side could remain the same.

The thing I am not sure on is transmission mating. The gen5 engines have either a 6, 8, or 10 speed transmission depending on application. A standalone will let you use a 4L transmission, but I am not sure what is required in terms of flexplate or torque converter.
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Pevious Jeeps: 1981 J10, 1975 Cherokee, 2008 JK, 2005 KJ, 1989 XJ

Topic author
Laredo Matt
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Re: Direct fit -- upgrading a 2004 (Gen 3) 5.3L LS to a Gen 5 2019 5.3L?

Post by Laredo Matt »

Thanks Stuka and all fair points.

My post was more focused on engine (specifically block) fitment but you are spot on wrt all the other components and changes to consider. My current plan is to purchase a newer complete drivetrain (engine, trans, transfer case) from a low mileage salvaged 4x4 vehicle. It would come with computers, trans controller, harness etc.

I really want to avoid moving frame mounting locations etc. as I don't want to change weight distribution, fitment in engine bay etc. My thinking (hope) is that If I stay in the same motor family ie. Gen V LS vs. current Gen III LS and same displacement (5.3L) the motor mounts points on the frame won't need to change. At least I have my fingers I've got my fingers crossed. Given differences in block dimensions (minor but there are some) i'm still trying to do my research to make sure that is the case.

If not, I'd consider other options / displacements and really kind of like the idea of diesel. Still a lot of decisions to make. For now, trying to progress on body and paint. As everyone knows here, a lot of blocking and sanding left to get it to a point its ready for color.
Matt
83 Cherokee Laredo WT
L8T 6.6L, 6L90
GEN III LS Swap (LM7 block)
4L60E

rocklaurence
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Re: Direct fit -- upgrading a 2004 (Gen 3) 5.3L LS to a Gen 5 2019 5.3L?

Post by rocklaurence »

I believe the mounts are the same: engine, trans etc. You will need a lift pump to feed the High Pressure fuel pump that is mounted on the engine. Stucka is correct regarding the ECM/controls and finding someone to tune these will be harder because theyre new.
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Re: Direct fit -- upgrading a 2004 (Gen 3) 5.3L LS to a Gen 5 2019 5.3L?

Post by babywag »

rather than spending a bunch of $$$$ on later setup...
why not swap in a gen iii 6.0?
uses same pcm(just needs reflash/tune), wiring, etc. etc.
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'88 GW (aka Babywag)

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Laredo Matt
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Re: Direct fit -- upgrading a 2004 (Gen 3) 5.3L LS to a Gen 5 2019 5.3L?

Post by Laredo Matt »

babywag wrote: Fri May 14, 2021 12:58 pm rather than spending a bunch of $$$$ on later setup...
why not swap in a gen iii 6.0?
uses same pcm(just needs reflash/tune), wiring, etc. etc.
The jeep came with a gen 3 5.3L but no history, high mileage etc.

Since I want to do the entire drivetrain, including 8 speed trans and transfer case, this seems like the smart route. All components matched from factory. Plus new features like Dynamic fuel management will improve mileage and overall drivability.

Tune will take some time to get everything deleted but plan to use factory harness as well not to mention all accessory components. I'm building a daily driver that is still capable off road (light to medium) on occasion but modern and reliable is more important. A bit more money but when you add in all the components included not as big a difference and for the intended use and with low miles it seems like a smart path in the long run. Still haven't pulled the trigger but leaning this direction.
Matt
83 Cherokee Laredo WT
L8T 6.6L, 6L90
GEN III LS Swap (LM7 block)
4L60E

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Laredo Matt
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Re: Direct fit -- upgrading a 2004 (Gen 3) 5.3L LS to a Gen 5 2019 5.3L?

Post by Laredo Matt »

rocklaurence wrote: Fri May 14, 2021 6:42 am I believe the mounts are the same: engine, trans etc. You will need a lift pump to feed the High Pressure fuel pump that is mounted on the engine. Stucka is correct regarding the ECM/controls and finding someone to tune these will be harder because they're new.
Tune is one I'll need to solve. Will definitely need to delete several features. I have a buddy who has been a ford mechanic forever and has all the right computers. He may at least be ale to point me to a tuner if it isn't something he wants to do. Need to fully think through that side of the equation as well.
Matt
83 Cherokee Laredo WT
L8T 6.6L, 6L90
GEN III LS Swap (LM7 block)
4L60E
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jpswapmohn
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Re: Direct fit -- upgrading a 2004 (Gen 3) 5.3L LS to a Gen 5 2019 5.3L?

Post by jpswapmohn »

read ALL of this: http://www.ifsja.org/forums/vb/showthread.php?t=188457

cu4whln is the first person I am aware of that has swapped in a new LT version motor. In my consideration of going the same route, it has been very informative. He is a great guy and always willing to offer information/support. In our discussion, he honestly recommended that I find a shop that is capable of doing the swap for me based on the many considerations he had to work out and cost.

From what I can tell, my having an early LT1/4L60e in my rig, or having a Gen III or IV swap in yours will have little impact on getting a GEN V powertrain into one of our rigs. Essentially, we will have to start with a clean slate from the frame rails. He went through a few different considerations for motor mounts. He did land (if I recall correctly) on a mix of LS motor mount bases and LT engine mounts. Everything else appears to be different.

I am still in the research stage of this swap, so I have no real personal experience to offer. From what I have read (internet never lies..), the LT swap wiring is simpler than the LS based on it being largely self-contained with the ECM and trans controller in the trans..

Hope that helps you on the journey. PLEASE let us know how you progress!
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Topic author
Laredo Matt
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Re: Direct fit -- upgrading a 2004 (Gen 3) 5.3L LS to a Gen 5 2019 5.3L?

Post by Laredo Matt »

jpswapmohn wrote: Sun May 16, 2021 6:34 pm read ALL of this: http://www.ifsja.org/forums/vb/showthread.php?t=188457

......

Hope that helps you on the journey. PLEASE let us know how you progress!
Great thread....thanks for the pointer! I was only able to start it this morning before work.. Have my afternoon reading now :)
Matt
83 Cherokee Laredo WT
L8T 6.6L, 6L90
GEN III LS Swap (LM7 block)
4L60E
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