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why not 4.0L in a 56 CJ5

Discussion in 'Early CJ5 and CJ6 Tech' started by muttboy, Jan 14, 2011.

  1. muttboy

    muttboy New Member

    Ok folks. Same 56 CJ5 from earlier posts. I'm sure I don't want a diesel now. Got lots of easier to acquire parts in my orbit. I still kinda wanna keep the F134 just to see what its like. But, I really want a FI 4.0L. So, give me some good reasons why I can't use one. Advance Adapters says I can with the S465 (plus I get 4spd!) and the stock T-case. However, I keep getting different answers. Anyone got some dimensions and specs? I realize that the fan shroud must go. No problem there. I'm only concerned with too much weight ahead of the front axle I'm also curious if the stock front axle is stronger than the D30. I want disc brakes on my resto-mod, ya know? Whatcha got?!
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  2. bkd

    bkd Moderator Supreme Staff Member 2022 Sponsor

    it's gonna be way to long to fit under the hood w/o major modification.......
    Jim
     
  3. Eaallred

    Eaallred Member

    Find an old Buick V6 to stuff in there. It fits like a glove,and has GOBS of power. I found a late 70's 231 even-fire for mine and I LOVE it. About 100 lbs lighter than the F134 was too!
     
  4. jasonjp62

    jasonjp62 Member

    only way you might get a 4.0 to work is to cut the front crossmember out of it and use a postal jeep grill. you will need to use the shortest water pump you could find. the i6 motors in the postal (which has the same wheel base as our jeeps) the motor is just over 30" long from the fan to the back of the motor. they also used a short water pump and there was no spacer between the fan and pulley. And they fit pretty snug in the postals.

    get out your measuring tape!
     
  5. duffer

    duffer Rodent Power

    Like bkd said-just too long for the stock wheelbase and any hope of keeping the radiator behind the grill. I have seen some real hack jobs with a radiator mounted to the cage so I guess just about anything is possible. But if you want a useful vehicle, put in a V6 or, my choice, a sbc.
     
  6. timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Yep - way too long.

    It can be done though ... I have seen a Chevy 230 in a '3A and a Ford 170 in a CJ-6. The Ford 144/170/200 is fairly short as inline 6s go, but they still had to make a box to move the firewall back. And the back of the valve cover was under the cowl.

    However, there's really no good reason to do it, when there are so many excellent V6s in the wrecking yards today. A V6 would make your task much easier.

    If you want EFI, go with the Chevy 4.3L V6 and use its native fuel injection. There's a lot of info on the Novak site http://www.novak-adapt.com/knowledge/chevy_small_block_v6.htm
     
  7. ojgrsoi

    ojgrsoi Retired 2024 Sponsor 2023 Sponsor 2022 Sponsor

    x2
     
  8. 54cj3b

    54cj3b Member

    I went 4.3 direction and glad I did
    [​IMG]
     
  9. muttboy

    muttboy New Member

    Posted via Mobile Device
     
  10. wingtime

    wingtime Member

    I hate to say but if you want a 4.0 Jeep it will be easier just to buy a YJ wrangler with one in it! If you love round headlights put one in a CJ-7 or a late model CJ-5... it's way too long to put in a early CJ-5.
     
  11. jasonjp62

    jasonjp62 Member

     
  12. 43 willys

    43 willys New Member

    I did accomplish putting a 4.0 in a 56 cj5 but the only thing left is the windshield hinges. The front fenders, hood and grill and frame are all longer when they went to the amc six (232 258 and 4.0) I ended up using a 05 unlimited frame, 4.0 auto and a repop cj6 body with 72 up front clip. The wheel base is close and it is cool but man is it a lot of work. The jeep is not mine but i am building it for a friend.
     
  13. jasonjp62

    jasonjp62 Member


    So none of the jeep is now a 56 (short wheel base jeep) 72 or newer is 5" longer in the front end anyway!
     
  14. 43 willys

    43 willys New Member

    Yes its really sad but like I said not my jeep, he wants to drive it on the street and take it to car shows.
     
  15. Jim302

    Jim302 Banned

    For more clearance, a water pump that bolts to the side of the engine not the front.
    Lower the engine and raise the cab up to help slide the engine back. But, to much of that will rule out almost all automatic transmissions.

    You can fit any engine in any vehicle it is a mater of how much effort you feel it is worth.

    "get out your tape measure"


    I personally hate 6 cylinder engines because of the torsional vibrations they produce. My CJ has not even arrived yet and i am prepping a SBC to go in.
     
  16. timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Hate? :?

    I looked this up and it's not clear to me that V8s are any better in terms of tortional vibration. Generally inline sixes are considered the smoothest multicylinder configuration without using a secondary balance shaft.
     
    Last edited: Jan 16, 2011
  17. oldtime

    oldtime oldtime

  18. Patrick

    Patrick Super Moderator Staff Member


    Does someone make a water pump that bolts to the side of an AMC 6?
     
  19. jasonjp62

    jasonjp62 Member

    not that i'm aware of!
     
  20. Mcruff

    Mcruff Earlycj5 Machinist

    I think he means an electric water pump. Not sure though!
    As for torsional vibration the less cylinders you have the more torsional vibration you have, a 4 cylinder has 2 pulses, a 6 cylinder has 3 pulses and a v8 has 4 pulses. The more pulses the less the harmonics are and the less torsional vibration, providing your not working with an oddfire like a Dauntless motor or a 5 cylinder, v10 or Harley style twin.
    I'm sure there are other that don't fit in this category but really the vibration is not really that noticeable in modern engines. Older motors due to imbalance and cruder machining more so than modern motors. I personally think your hate is misguided.