Engine swap
- Thread starter Kip8080
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john e denson
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- Dec 3, 2020
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john e denson
Full Access Member
- Joined
- Dec 3, 2020
- Messages
- 61
- Reaction score
- 20
I am pretty sure 2002 to 2004 are a direct swap. then 2005 to 2012. You can check treads in here to find out for sure
Engine Swap Overview
So my '03 started with a very mild internal tapping noise last summer that would come and go. But just before Christmas it transitioned to a definite knock that only got worse. Three weeks ago it got so bad that listening to the radio was a waste and my neighbors could hear me coming. Since I'd...
www.jeepkj.com
Good info here.
^^^ That’s the thread I was going to suggest they read. The 02 is a bit of a unicorn. Details in that thread.
24turbo
New Member
Only potential problem I can see is the centering button on the front face of the torque converter. The 42RE transmission (03 onward) button is smaller than the 45RE transmission (02 model year and early 03). 03 and newer crankshafts have a pressed in spacer to compensate for the smaller button on the 42RE. Not sure if not having this button "center" the TQ to the crankshaft (because it is too small to fit properly) would cause long term problems.
I did the opposite and put an 03 into a 02 and had to remove the spacer to get the torque converter to seat properly. It was not easy to get out.
I did the opposite and put an 03 into a 02 and had to remove the spacer to get the torque converter to seat properly. It was not easy to get out.
Shankster
Full Access Member
Yes it is. I do not believe a 2002 and 2004+ are directly interchangeable though - The 02 and 03 have a 12 tooth reluctor ring on the crankshaft and the 2004 and later have a 32 tooth reluctor ring. You would either have to use the computer and sensors that came with the engine or completely disassemble both engines and swap the reluctor ring over. I wasn't aware of the issue with the button on the torque converter so that sounds like another reason to avoid the swap.
I went with this short block and it's been doing great for a couple of years. The owner also seems very knowledgeable and answered any dumb questions I had:
2002 2003 Dodge Ram Jeep Liberty Nitro 3.7 Engine Short Block JTECH
Contact us for price and additional information THIS IS A COMPLETELY REBUILT SHORT BLOCK ASSEMBLY, THAT INCLUDES NEW PISTONS ,RINGS ,BEARINGS(MAIN,ROD,THRUST WASHERS AND BALANCER). FREEZE PLUGS AS …
I just went through an engine swap for a 2003 3.7L . Got a reman engine from Tristar (Autozone) which failed in less than a month. Took 2 months to get a replacement, which appears to be failing as well (consistent cyl misfire, probably a bad head).
Regarding your simple question, there is no simple answer. Yes, a block is a block... and your block is the same as any 2002 or 2003 chrysler 3.7L v6, including the Ram 1500 3.7L v6, so the block should be a direct swap. However, there's more to it than just the block.
Your new engine, old trans, old ECU and old TCU will all have to be reviewed to see if all 4 are compatible. If not, then expect additional high costs to make them so.
I tried to save my Liberty because I took exceptional care of it for 20 years and it looks like it just rolled out of the showroom yesterday. My swap experience turned out to be a complete nightmare, I totally regret doing it, and I strongly recommend that you shrug your shoulders and get another vehicle.
Don't be sentimental, its just transportation.
I will add another experience that is different that dtennes’ but does not invalidate their ordeal. So sorry the engine swap turned out to be a debacle! That totally *****.
I replaced the engine on my 2008 KK in 2014. It had a bad rod bearing, probably from the factory, as it only had 86k miles on it. I had built my Jeep up with a lift and tires, skid plates, sliders, and other mods and didn’t want to start again from ground zero.
I went with a Jasper remanufactured engine. These go through rigorous reconditioning, where they also fix inherent factory problems. They come with a 3 year, 100k mile warranty that INCLUDES labor. My Jeep is now at 217k miles and the Jasper engine is still happy. I have no data on it, but I would say it runs smoother and makes slightly more power than the original. Anyhow, Jasper stands behind their remanufactured engines and transmissions and I highly recommend using them even though it is more expensive at the front end.
I replaced the engine on my 2008 KK in 2014. It had a bad rod bearing, probably from the factory, as it only had 86k miles on it. I had built my Jeep up with a lift and tires, skid plates, sliders, and other mods and didn’t want to start again from ground zero.
I went with a Jasper remanufactured engine. These go through rigorous reconditioning, where they also fix inherent factory problems. They come with a 3 year, 100k mile warranty that INCLUDES labor. My Jeep is now at 217k miles and the Jasper engine is still happy. I have no data on it, but I would say it runs smoother and makes slightly more power than the original. Anyhow, Jasper stands behind their remanufactured engines and transmissions and I highly recommend using them even though it is more expensive at the front end.
Shankster
Full Access Member
There are reputable engine builders out there who will send you a good engine and stand behind their product. I agree you need to do the math (will my vehicle be worth at least the salvage value + what I'm putting into it?) and if it doesn't add up it's probably best to have the thing hauled away. I spent less than $2k all-in on my engine swap (flengines4less short block) and I have a perfect running (touch wood), pristine 02 Limited now so mine worked out well.
That's disturbing about Autozone - I bet they source engines from a mass production budget rebuilder (somewhere south of the southern border) - I think a small shop specializing in these engines is probably the better way to go and they know how to fix some of the things Mopar screwed up 20 years ago. And you give them your VIN and they'll send you something guaranteed to work with what you've got.
Shankster
Full Access Member
Looks like we were typing at the same time - well said, lfhoward! I looked at Jasper engines but they were beyond my budget.
I'm honestly happy that you had a good experience. I didn't want a Tristar, actually picked out a block that had been re-milled to fix the porting issues from the original design.... and then the shop went ahead and bought the Tristar and stuck me with both the tab and the fallout. Saw the post about Jasper engines and by coincidence ran into a guy today that bought a trans from them that ran great.
Shankster
Full Access Member
My apologies if my post came across as a criticism - wasn't meant that way. I don't think you did anything wrong or made a bad decision - seems you just got really unlucky, twice, which totally *****. And I see that Tristar remans their engines in the US, not south of the border. I guess the main point I was trying to make was that (I assumed) the vast majority of these reman engine swaps turn out good. Then again, how would I know that, I don't have the stats. It would be interesting data if only it existed and would help with these tough decisions.
Lol, didn't read it as criticism so no worries there. I'm going to add a little "tales from the trenches" commentary immediately following...
"Tales from the trenches" or "Things to keep in mind if you are going to do a KJ engine swap":
1. If it's a KJ Liberty, it's not just an old vehicle. It's been obsolete for over 20 years.
2. Certain parts have a long, but not infinite life span: MAP, IACV, TPS, IAT, O2 sensors, manifold breather valves, PCV, etc. Best to assume that anything you can touch probably needs to be replaced.
3. Finding parts for a swap is a challenge, and in some cases impossible. Example: Specifically a 2003 3.7L Crank Pos sensor. It should be a match for the 2002 and 2004... but there is no explicit association in any catalog anywhere, only the implication that because the 2002-2004 3.7L blocks are identical, the CKS *should* be the same across all 3 years.
4. Chinese aftermarket parts on AMZN are univerally garbage and will only create ratholes you do not want to deal with. NEVER USE THESE PIECES OF GARBAGE. Maybe some established AutoZone/Advanced/OReilly retailed parts from mans like Echlin are ok, but stick with true Mopar, or Crown Automotive for reliability.
5. From trial and error, Mopar is obviously the #1 reliable replacement source, #2 is Crown Automotive (especially for anything to do with sensors and engine controls like the TPS, IACV, etc), #3 and 4 are interchangeably NGK and Bosch.
6. You are dealing with 20 YO wire harnesses and connectors. There will be fraying, crumbling insulation, and 4th rate garage goofs will eventually destroy every single engine sensor connector in your vehicle by breaking the locking tabs causing downstream electrical connection failure. Check the locking tabs on all connector housings and inspect for kinks (there will be broken strands under the insulation). Read my posting on "How to build ignition wiring replacement", and use that as a guide to also build replacement wiring and connectors for various sensors/etc. https://www.mouser.com/ is my goto for electrical component rebuild components.
7. If you blow a ring, you will need to replace the catalytic exhaust because it will be totally fouled, and you'll get all kinds of MIL codes. Make sure all O2 sensors are replaced when the new CC goes in, a new CC doesn't do much good if the sensors are whacked.
8. You should plan on replacing all of your sensors in general. I ultimately did because engine fouling can/will wreck your MAP, IAT, Evap Solenoid... and I simply got to the point where I decided to bite the bullet and do everything.
9. There's a few more odds and ends but anyone that does this job will figure those out in due course without any big surprises.
10. After all that, in my mind, the biggest threat to a successful swap is probably the fuel delivery system. This is where the risk of obsolescence really kicks in. I have been avoiding the very contemplation of replacing the fuel pump because while OEM is generally available (make sure you have a *visual* match, because there are supposed replacements that are not spec), you need a very specialized part to do the job. That part is a circular locking flange that is necessary to seal the gas tank after you replace a fuel pump. This part is obsolete, and NOBODY makes them, especially Mopar. If you ruin the original part, the only place you can get one is a yard. You have to either drop the tank, or cut through the floor of the cargo area to get at it, so yard salvage is a nightmare. Even if you find one, it will probably be thoroughly corroded unless you luck out and find something that was garage kept for 20 years. If you must do this, and get a good flange, hand the work over to a reliable garage to do the job right by dropping the tank for the install.
I think you get the perspective for my "walk away" suggestion. If you love to work on cars, this will certainly challenge you and I wish you good fortune. I've been unsuccessfully troubleshooting a lingering p0304 for the last 10 months, so what started as an acceptable "challenge" has evolved into pure frustration.
1. If it's a KJ Liberty, it's not just an old vehicle. It's been obsolete for over 20 years.
2. Certain parts have a long, but not infinite life span: MAP, IACV, TPS, IAT, O2 sensors, manifold breather valves, PCV, etc. Best to assume that anything you can touch probably needs to be replaced.
3. Finding parts for a swap is a challenge, and in some cases impossible. Example: Specifically a 2003 3.7L Crank Pos sensor. It should be a match for the 2002 and 2004... but there is no explicit association in any catalog anywhere, only the implication that because the 2002-2004 3.7L blocks are identical, the CKS *should* be the same across all 3 years.
4. Chinese aftermarket parts on AMZN are univerally garbage and will only create ratholes you do not want to deal with. NEVER USE THESE PIECES OF GARBAGE. Maybe some established AutoZone/Advanced/OReilly retailed parts from mans like Echlin are ok, but stick with true Mopar, or Crown Automotive for reliability.
5. From trial and error, Mopar is obviously the #1 reliable replacement source, #2 is Crown Automotive (especially for anything to do with sensors and engine controls like the TPS, IACV, etc), #3 and 4 are interchangeably NGK and Bosch.
6. You are dealing with 20 YO wire harnesses and connectors. There will be fraying, crumbling insulation, and 4th rate garage goofs will eventually destroy every single engine sensor connector in your vehicle by breaking the locking tabs causing downstream electrical connection failure. Check the locking tabs on all connector housings and inspect for kinks (there will be broken strands under the insulation). Read my posting on "How to build ignition wiring replacement", and use that as a guide to also build replacement wiring and connectors for various sensors/etc. https://www.mouser.com/ is my goto for electrical component rebuild components.
7. If you blow a ring, you will need to replace the catalytic exhaust because it will be totally fouled, and you'll get all kinds of MIL codes. Make sure all O2 sensors are replaced when the new CC goes in, a new CC doesn't do much good if the sensors are whacked.
8. You should plan on replacing all of your sensors in general. I ultimately did because engine fouling can/will wreck your MAP, IAT, Evap Solenoid... and I simply got to the point where I decided to bite the bullet and do everything.
9. There's a few more odds and ends but anyone that does this job will figure those out in due course without any big surprises.
10. After all that, in my mind, the biggest threat to a successful swap is probably the fuel delivery system. This is where the risk of obsolescence really kicks in. I have been avoiding the very contemplation of replacing the fuel pump because while OEM is generally available (make sure you have a *visual* match, because there are supposed replacements that are not spec), you need a very specialized part to do the job. That part is a circular locking flange that is necessary to seal the gas tank after you replace a fuel pump. This part is obsolete, and NOBODY makes them, especially Mopar. If you ruin the original part, the only place you can get one is a yard. You have to either drop the tank, or cut through the floor of the cargo area to get at it, so yard salvage is a nightmare. Even if you find one, it will probably be thoroughly corroded unless you luck out and find something that was garage kept for 20 years. If you must do this, and get a good flange, hand the work over to a reliable garage to do the job right by dropping the tank for the install.
I think you get the perspective for my "walk away" suggestion. If you love to work on cars, this will certainly challenge you and I wish you good fortune. I've been unsuccessfully troubleshooting a lingering p0304 for the last 10 months, so what started as an acceptable "challenge" has evolved into pure frustration.
Engine replacement checklist:
https://www.jeepkj.com/threads/engine-replacement-checklist-kj-2002-2003-and-maybe-2004.80359/
https://www.jeepkj.com/threads/engine-replacement-checklist-kj-2002-2003-and-maybe-2004.80359/
