Engine Swap Overview

Discussion in 'How To' started by TwoBobsKJ, Mar 9, 2013.

  1. TwoBobsKJ

    TwoBobsKJ Full Access Member

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    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 already found a donor engine, and I had very important customer visits that required I get this done, I decided I'd do the swap even though it was COLD around here at the time. Thankfully the garage has a heater that came in very handy.

    Here's why it was past time to replace my original engine:

    [​IMG]

    Found an '07 engine from a Dodge Dakota with only 9700 miles. Some topside damage - broken upper radiator neck, power steering pump and the plastic valve cover was broken. Other than those broken parts though, it is exceptionally clean and mechanically sound. With the exception of the valve cover and the timing cover the broken parts had to be swapped out for those on the original engine.

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    Side view:

    [​IMG]

    So if you have an '03 or '04 Liberty and you want to swap in an engine from an '05 or newer (even up to a 2012) here are external components you'll need from your original engine (same components from new engine will likely be different):

    • Intake manifold
    • Oil pan
    • AC compressor, alternator, power steering pump, water pump
    • Original motor mounts (or new; more on that later)
    • Exhaust manifolds
    • Oil filler neck
    • Oil drip pan (under the oil filter)

    Internally, the right side cam sprocket and crankshaft reluctor ring must match your computer. The '02 through '04 use the JTEC computer; '05 and later use the NGC computer, so you have two options. One, pull the cam sprocket and reluctor ring from your original engine and then break down the donor and install the originals in the donor. That means you're tearing down two engines- that's a lot of work. So I purchased a cam sprocket, reluctor ring and EGR blocking plate from Engine-Guru.com so that I only needed to break down the new engine instead of both of them.

    Here's the reluctor ring for the crankshaft (1st pic) and the cam sprocket in the 2nd pic. You'll probably need to get three new T-27 screws for the reluctor ring (I did) and they're dealer-only (about $1.25 each); the screws were installed at the factory with thread lock so it's easy to strip out the screw heads. I didn't take a pic of the EGR blocking plate (new engines have an external EGR valve that your older engine doesn't have) but it's a simple 1/4" steel plate in the shape of the valve:

    [​IMG]
    [​IMG]

    If we only needed to swap out the cam sprocket we'd just take off the timing cover to remove the timing chains. But we also need to swap out the reluctor ring which is attached to the rear portion of the crankshaft - so the crank has to be removed. The 3.7 has a two-piece block, so the lower section - the bedplate - must be taken off to remove the crank. So that means the main bearings and bearing caps for each of the connecting rods is taken off to get the crank out. Get a copy of the Factory Service Manual for detailed instructions, torque specs, etc. to learn how to do both procedures. It looks intimidating at first but take it step-by-step and you'll be fine. One note: Some folks on other forums have had to remove the pilot bearing on the end of the crank so the nose of the torque converter will fit. I did NOT have to do that but compare the size of the opening in the end if your original crank with the donor motor's crank. If the pilot bearing has to be removed so your torque converter will fit you may need to take the crank to a machine shop. That bearing is pressed in very tightly and won't come out with a pilot bearing puller.

    Timing chains (new engine - nice and clean):

    [​IMG]

    Bedplate and crankshaft removed:

    [​IMG]

    IMPORTANT!! The connecting rods use "torque to yield" (TTY) bolts and MUST NOT be reused. They are not easy to find (not available at standard parts stores) and have to be ordered through the dealership. They cost me $1.20 each plus $4 shipping from a dealership in central Ohio - plan ahead on that one.

    The timing cover is the same on 3.7 blocks through at least 2010 so you don't have to replace that (I used the cover from my original engine due to the accident damage to the donor motor) but when you remove it you will have to install new gaskets. Besides the gaskets for the timing cover, you'll also need gaskets for the water pump, valve covers, intake manifold, exhaust manifolds and oil pan. The front crank main seal gasket comes with the timing cover gasket set so you're good there. But you'll certainly want to replace the rear main seal too if you have to remove the crankshaft to swap the reluctor ring so order one before you get started. The oil pan gasket is also the windage tray. Here's what it looks like:

    [​IMG]

    Once I got the old engine out it was obvious the original motor mounts were shot:

    [​IMG]

    NAPA carries them so I replaced the pair for $80.

    One frustration I ran into as I was wrapping things up - the power steering pump wouldn't bolt into the cylinder head! The '07 pump uses different bolt locations than the '03 - however, the bosses are in the correct place to put the '03 pump on the '07 cylinder head. Just have to run a tap into the bosses that are cast on the head. The pic below shows the bosses that need tapped; the other 3 are for the '07 pump bolts. Use an 8M X 1.25 tap; casting sand is all that is in the hole locations in the head so it's an easy 10 minute job.

    [​IMG]

    After using lots of Lucas Assembly Lube on the internal parts - main bearings, all connecting rod bearings and the crankshaft journals - I assembled everything being very careful of torque specs and bolt tightening order. I put on the timing cover, exhaust manifolds and cats and the new engine was ready to go back in.

    [​IMG]

    Filled the engine with all fluids, put on the intake manifold and the accessory components, reattached the wiring, said a quick prayer (!) and turned the key and Bingo! it started right up. Put 1200 miles on it the next five days and it drove like night and day. Obviously the banging/knocking is gone but the old Liberty purrs like a kitten and has a definite power improvement.

    The project isn't technically hard but having a comprehensive tool selection is necessary. The most handy tool I used was a 36" ratchet extension I borrowed to get to the transmission bolts at the top of the bellhousing. Would have been a struggle to get to those bolts off and on otherwise. I had a bit of a challenge lining up the flex plate and torque converter bolts but finally got it.

    Hope this helps others considering an engine swap. Drop me a PM if you have any questions. :favorites13:

    Bob
     
    Last edited: Jul 24, 2017
  2. tommudd

    tommudd Moderator Staff Member Moderator

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    Great job and Thanks for providing this fantastic write up Bob !
     
  3. doolop

    doolop Full Access Member

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    I'm working on a complete rebuild (no writeup) this has helped. Thanks

    Sent by using tin cans and string
     
  4. Luke

    Luke Full Access Member

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    Good grief .. you are a magician :D

    much respect!
     
  5. Dave

    Dave Administrator Administrator Moderator

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    Nice Bob. I made this thread a "sticky".

    Dave
     
  6. Honduras

    Honduras Full Access Member

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    What about the wiring? You just used the 4.7 donor harness and nothing else? What about the ECM from the 4.7, etc.?

    Sent from my iPad using Tapatalk HD
     
  7. TwoBobsKJ

    TwoBobsKJ Full Access Member

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    This is an overview of a swap from an '03 3.7 to an '07 3.7L - not to a 4.7.

    Bob
     
  8. rockymountain

    rockymountain Full Access Member

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    did you keep the 07 PCV system? You won't get the sludge in the filler tube anymore if you did. Just wondering.

    Nice job!
     
  9. TwoBobsKJ

    TwoBobsKJ Full Access Member

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    Thanks Rocky!

    No I didn't because so much was different on the '07's intake and PCV system so trying to integrate with my '03 would have taken a lot of engineering.

    I am going to do the TSB on my '03 to get rid of the oil filler gunk eventually. I have to say though...I did a lot more highway driving this winter than past years and the gunk issue was not a problem. Getting these engines up to operating temp for an extended period of time gets rid of that condensation.

    Bob
     
  10. fouros

    fouros Full Access Member

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    How did you go with removing or moving the ac gubbins. I will have to do an engine replacement soon but managed to find a low milage engine from another 04 model
     
  11. TwoBobsKJ

    TwoBobsKJ Full Access Member

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    Having another '04 engine will help you immensely - both in cost and in the time it will take to complete the project. Having to break down the donor engine to swap out the reluctor timing ring and the cam sprocket added at least one full day to my swap.

    The A/C compressor can remain connected to all hoses - I simply moved it to the side and zip tied it to part of the front fender. It was well out of the way.

    Same thing with the power steering pump - grabbed a zip tie and held it off to the side.

    Hope this helps!

    Bob
     
  12. fouros

    fouros Full Access Member

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    thanks mate I appreciate the quick reply, out of interest, how long did it take you to do the swap ???
     
  13. TwoBobsKJ

    TwoBobsKJ Full Access Member

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    Too long...

    But I did it during a cold snap in February (our winter) and was on the road visiting customers during that time using a friend's car so it took me a couple of weeks all together. I worked on it at night and on the weekend when I was home.

    Actual working time was about 4 days I'd guess - but again, working in a cold garage (even with a heater) so I was getting up off the floor to get warm. Realistically I'd estimate a 3 day job for us do-it-yourselfers just working steady and assuming all parts, tools, etc. are in place and ready to go. Since you don't have to break down the new engine to swap the cam sprocket and reluctor ring - and also the exhaust manifolds, oil pan, motor mounts - you can probably do it in 2 days.

    Bob
     
  14. phantomrt

    phantomrt New Member

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    A bit of an old thread... gonna bump it a bit.

    I am on my 2nd 2002 Liberty engine swap, using 05 engines. Pretty easy job for an engine swap in my opinion. The 2005 engines are of significantly lower cost--by about $1,000. Even with locked up / jammed engines that required the torque converter to come out with the engine, there is plenty of room for that to be done. For engine lifting hooks, I took some old spark plugs and hammered off the porcelain and welded the end of a long bolt to the remains of the spark plug, and on the other end of the bolt, a big washer got welded to it so that I can hook a chain by it. I thread them into spark plug holes and I have a good point from which I can lift the engine out.

    I do not know why, but the 02's seem to be the ones with the most engine failures. The last one that I am doing right now had about a half a quart of oil in the pan... and according to the oil change sticker on the windshield, it had 1300 miles on that oil change. Its like the oil change never got done or never got done properly. I never really took either engine apart to diagnose the actual cause of failure--such as a valve seat falling out or something.

    As everyone knows, the NGC reluctor rings on both the camshaft and the crank need to be swapped. I find that catastrophic engine failures like to destroy those reluctor rings. My current project had about 1/8" of metal worn away on one of the teeth as a result of debris within the engine making contact with it, so I got the welder out and added metal back to it and filed it down so that it looks normal. Hopefully this won't affect the operation of the reluctor. I will find out relatively soon.

    There's that place on the internet--engine guru??-- that sells the crank reluctors for $100... a bit steep for my cheap wallet. My local crankshaft supplier was able to supply me one for $40. The part is not sold by Chrysler--they want you to service the entire crankshaft.

    Anyway, I can also verify that the intake manifolds are different, with the only real difference being what appears to be the absence of a charge air temperature sensor in the '05 engine.

    None of the engines that I dealt with so far had any EGR to dink around with.

    The 2005 crankshaft has an insert in the torque converter end that needs to be removed... much like removing a pilot bearing. Some persistence with a dremel cut off wheel gets the job done.

    Exhaust manifolds are different, but swap without issue.

    Oil pans are different, but will work either way. Aftermarket oil pickup tubes appear to be all the same. The dipstick tubes are the same as well, however the oil dipsticks themselves are different. The "full" mark on the 05 dipstick is significantly higher than on the 2002. If you look carefully at the 05 oil pan, the sump is shaped differently and is a bit smaller, but appears to be the same depth. What I believe happened is that they re-designed the oil pan to raise the oil level closer to the crankshaft without increasing engine oil capacity. So, I guess you could consider using a 2002 oil pan and using the 2005 dipstick to be an "upgrade" as it should increase oil capacity by about a quart. This re-design may have been an attempt to reduce the oil starvation related failures of these engines.... with the oil pickup in a smaller sump and deeper down, it should, theoretically, work. But essentially, over-filling a 2002 engine by about a quart should theoretically do the exact same thing.

    The timing covers are identical. The parts book suggest that the timing components themselves are different, as are pistons and such. They definitely change some stuff internal to the engine, but outside, its all the same.

    Oil pressure sending units need to be swapped. The crankshaft position sensors are also supposedly 2002 specific.... I am not sure why, but they were on big time back order at the dealer. The borg-warner aftermarket one is working fine for now. Yes, engine failures like to destroy these, too.

    Compression ratios increased in the 2004-2005 engines... I think. The engine controllers don't seem to care. It runs perfectly.

    According the the parts interchange, all the model year Liberty engines are model and year specific. Contrary to this, any 3.7 engine from any Chrysler vehicle all the way to 2011 at least should be able to work just fine. I've done lots of engine swaps over the years where the difference between an engine "fitting" and "not fitting" was a different shaped bracket, or a different oil pan, or just something else that is really stupid. THen there were situations where the books said they did interchange, but I had to swap pretty much every single item that bolts to the block--like a GM 3400 from a Buick Rendevous to a Grand Am. Literally, EVERYTHING was different outside of the engine.
     
  15. TwoBobsKJ

    TwoBobsKJ Full Access Member

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    Nice update - thanks for the detailed write up. :waytogo:

    Bob
     
  16. phantomrt

    phantomrt New Member

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    I just finished up the 2nd swap. All went well aside from the radiator that just happened to spring a leak coincidentally. The 2nd engine installation went far smoother than the first one, and even the first one wasn't even that bad.

    I have roughly 900 miles on the first swap. It runs and drives perfectly with no check engine light or anything like that.

    I will add that the fuel injectors are different--so they appear. I never tried to see if they will plug in or not, but I just swapped them anyway. The '05 fuel rail seems to be all stainless steel, while the '02 is a bit of both, it appears. Either way, they will swap.

    Valve covers are different--the '05 covers are plastic, and the '02 are stamped steel. Again, they swap without issue. I believe that they even use the same gaskets.

    The '02 engine has a lock ring securing the timing chain idler sprocket onto its spline. the '05 does not have it, but the provision is there. It looks a bit scary to not have it in place, but it has worked for the last 10 years without issue.

    My weld job to the slightly damaged crankshaft reluctor ring didn't seem to affect anything. Perhaps what I did was totally not necessary, but in either case, it seems to be working right now.

    So, hopefully these things sell well--I will have five cars up for sale--2 1998 XJ Cherokees, 2 KJ Liberties, and an '05 Impala. The last Jeep that I still have will be the one I keep.
     
  17. johnnysuds

    johnnysuds New Member

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    Engine swap 2004 liberty

    Hey guys, I've got a 2004 liberty with a bad 3.7, I also have a 1997 jeep grand limited with good drive line and was hoping for some insight on a 5.2 swap into the liberty .
    Has anyone done or heard of this being done before?
     
  18. Snail Farmer

    Snail Farmer Full Access Member

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    I measured a 5.2.. it's too tall to fit in a liberty without major modification
     
  19. mx3_ryder

    mx3_ryder Full Access Member

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    For those doing the above swap, up to and including 2012 will work in 02-03 models. 02 and 03 Liberty's with the 45RFE transmission will need the pilot bearing or insert removed in end of crankshaft to accept torque converter. Check fitment of torque converter before mating transmission to engine
     
  20. nlocascio

    nlocascio Full Access Member

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    So from reading, it sounds like since i have an 02 liberty, it would be a good idea to overfill by half a quart of oil? Also what is the main source of these engines burning oil? Valve seals?