2002 3.7l engine parts compatability

Discussion in 'KJ General Discussion' started by garden_t00l, Oct 16, 2016.

  1. garden_t00l

    garden_t00l New Member

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    Hi, new here and trying to help my parents get their jeep back on the road. Its a 2002 liberty sport with the 3.7l They were told that the engine is different than a 2003, but everything I could find shown that the engine is the same up to 2004 changing a bit in 2005. It needs a head replaced and the number 1 piston replaced. I glanced at the head and it for sure has a bent valve, broken valve seat and some other damage which may or may not be from my cousin trying to work on it for them. I was told the lobe was worn down on the cam, but have not seen it as it had already been taken apart. It also got the piston pretty good. So heres my question if as they need to keep the cost down. I would just like to double check that a head will fit from a 02-04 engine and if they decide to go the other route will a 02-04 engine basically drop in?
     
  2. TwoBobsKJ

    TwoBobsKJ Full Access Member

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    The short answer - yes, any Chrysler product's 3.7 from 2002 through 2004 will work, meaning you DON'T have to get an engine from a Liberty to make it work on your parents' Jeep. All of the 3.7 blocks are the same up to at least 2012 - but as you mentioned, starting in 2005 the computer used in Chrysler products changed and so the cam sprocket and reluctor ring are not compatible in the later years with your 2002. However, you can purchase the sprocket and ring for the '02 thru '04 and put them in a newer block and all will play nice with each other.

    Take a look at the Engine Swap Overview sticky in the How-To section for more details.

    If you want to grab just the cylinder heads from a newer engine you won't have to change the sprocket and ring out since you'll be using yours. I'd suggest putting in new heads for both sides since the machining may be a little different on a newer year head than the '02. The compression ratio is actually higher on the later model years than the '02.

    Hope this helps :waytogo:

    Bob
     
  3. Conundrum2006

    Conundrum2006 Full Access Member

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    If your talking to a junk yard / salvage yard their interchange is more limited than what will work, the Hollander interchange they use is based a lot on what the factory says, so it misleading because the factory doesn't often come back to correct errors. That's why I'll go between the Hollander interchange and aftermarket if In doubt.

    Any Chrysler 3.7 engine between 2002-04(?) will drop in with minimal swapping of things like oil pans and sensors. Even Mitsubishi used the 3.7, but I think that's started after 06


    I think you can use any head to 2012. Don't worry about egr on a non egr car (if you don't have egr) As long as you use the original exhaust manifolds the egr is out of the exhaust loop.

    I thought the passenger side cam rear where the sensor is might have changed but that's a easy swap if it is diffrent.
    The biggest challenge aside from parts is going to be putting the timing back correctly but there are some good write ups on this as well.

    I don't know what you budget is but a new motor might be faster, then again in checking the used prices around me and the prices are too high for 13 year old 100k mile motors.
    Some people here have gotten a 3.7 from eBay that was originally for the Mexican market Maybe that's an option as well



    Sent from my iPhone using Tapatalk
     
  4. Logan Savage

    Logan Savage Full Access Member

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    I'm a little confused about the 02 -04 working . After reading this thread & others I went on ebay & put in 2004 jeep liberty pcm . All the pcm's had 4 connectors . My 05 has 4 & my 02 has 3 .
     
  5. renegade 04

    renegade 04 Full Access Member

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    The reason why the 2002 and some 2003's had 3 connectors is due to the they had external transmission control modules. From 2003.5 forward, with the exception of CRD's all the PCM's had 4 connectors due to a integrated transmission control module.
     
  6. TwoBobsKJ

    TwoBobsKJ Full Access Member

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    Yep, the '02 thru '04 Libbys use the JTEC computer while the '05 and later use the NGC computer. The tranny controller was changed but that didn't affect the engine controller.

    If you put an '05 or later 3.7 in an '04 or earlier you'll need to change the cam sprocket and reluctor ring.

    Bob
     
  7. 04Liberty

    04Liberty Full Access Member

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    Also keep in mind if you swap or have to replace a head to use the matched set cams, cam timing changed a bit in 05.
     
  8. Roepar79

    Roepar79 New Member

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    2002 3.7 into a 2004 ?

    Hey Guys,
    I picked up a 2004 KJ with a blown engine and I have a 2002 takeout 3.7 engine(100k miles)from my brothers wrecked libby is this compatible?
    I've heard of the other way around but not a 02 into a 04
    Thanks
    Roepar
     
  9. TwoBobsKJ

    TwoBobsKJ Full Access Member

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    Short answer - no, the '02 won't swap into an '04 directly without changing the cam sprocket and reluctor ring from the blown '04 into the '02 from your brother. Read through the Engine Swap Overview to get an idea of how this works - except in reverse in your case.


    Bob
     
    Last edited: Jan 5, 2018
  10. Roepar79

    Roepar79 New Member

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    Bob
    Thank you , and for that helpful (engine swap overview) info.
    Roepar