Engine swap questions

Discussion in 'General Tech' started by JSJJ388, Jul 11, 2019.

  1. JSJJ388

    JSJJ388 GREEN GREMLIN

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    Probably dumb questions, but I can be dumb at times. Im getting closer to swapping my AMC 360/TF727 into my ZJ. Ive got most of the major bits worked out, but I have a few questions for those who have done similar. Ive pulled and rebuilt engines, but have never swapped an entire driveline into a vehicle that wasnt built for it.

    For a fuel pressure regulator to take the stock ZJ pressure to carb levels, do I need one with a return? Or will a returnless one do the trick. I believe the fuel pump uses the fuel flow for cooling, so Im unsure.

    For those with stand alone engine setups in rigs you drive on the road, what are you using for main ignition switch and gauges? My plan is to use the computer to control the fuel pump, lights, and all the other odds and ends while having the engine be stand alone. Its a carb engine, so I dont see any issues with this. Am I missing something? Thinking of using this with one switch for the stock systems and one for the engine:https://www.amazon.com/JIANFA-Flip-...=gateway&sprefix=racing+switch,aps,135&sr=8-6 Would this work?


    And lastly, what are you guys using for engine and trans mounts? I can draw up some mounts and make them, but they would be solid and not have any give. Works fine in a race car, but is that ok for something thats still going to be on the road? For the trans mount, I imagine Ill have to move its location, so whats the best way to approach that on a unibody?

    Im sure as I work through this Ill have other questions. Feel free to give any advice youve learned along the way.
     
  2. Scooter402

    Scooter402 Rest in pieces

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    Dumb questions? No such critter (usually). But here's my take on what you ask.

    Fuel pump - I'd go with an engine mounted mechanical pump. They can be had for less than $30, and would be much easier and cheaper than a return style regulator. IMHO I'd say you need a return style regulator if you were to go with the in-tank pump. I don't think it would last long as a dead-head. If you don't want a mechanical pump, I'd get a Holley red pump (no need for a regulator, unless you want to dial the pressure lower than 7 psi) or a blue pump that should come with a regulator.

    You can find in the existing wiring harness a switched 12V wire to fire your ignition. Gauges would be very simple if you don't plan to use the stock dash. Aftermarket gauges for oil pressure, coolant temp and battery voltage would all be easy to hook up. And if you know what ohm range your fuel sender in the tank is, you can get an aftermarket gauge to match the rest. All of the above I did when I swapped the 2.5L out of a YJ for a 350. I honestly don't know how the ECM would act with the fuel pump with not having any feedback from the engine. Some will cut fuel feed if there is no ignition signal. Notice that when you turn on the key, it probably primes for 2-5 seconds, then shuts off until it gets an ignition signal. So if you don't figure out how to tell the computer that the cylinders are firing, it won't deliver fuel. That is, unless you wire the fuel pump with a switched 12V signal...then problem solved.

    The only issue I see with solid engine mounts is more vibration felt. You can get some "universal" engine mounts that do have a rubber puck in them. That's what I had in my YJ, and what I have in my CJ as well. Not knowing the frame width of your ZJ, I don't know if it would work.

    For the trans mount, I'd try and measure roughly if you can before you start to see if you can use your existing holes in the frame and fab something to use those. They're already there, so why not try to use them if you can. Otherwise, you might have to get creative and come up with something different. Pictures of your setup would help, since I'm not really sure what the unibody looks like under a ZJ. I've only spent limited time under an XJ, and I'm a little lazy right now to play Google ninja.

    Hope that helps. I might offer my useless opinions again should more discussion/questions arise.
     
  3. Jody Treadway

    Jody Treadway Croc wearing fool Moderator

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    Are you keeping the AMC 360 carbed? If so, run the stock mechanical pump. You'll spend a lot of dough to regulate the stock pump down to carb pressure.
    The trans mount will be a piece of cake. The 727 mount holes will share a very similar bolt pattern as the ZJ transmission does. I would make your own motor mounts adapting the stock AMC mounts to your own frame mounts.
     
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  4. JSJJ388

    JSJJ388 GREEN GREMLIN

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    Had not thought of using the stock mech pump... I am good with using that. Thanks.

    I will either have to replace the stock switch or go aftermarket as my stock switch no longer has the spring loaded "start" position. I currently have a push button under the steering column and want to move it. Push button is fine, just hate where it is. Fuel gauge was my main question. I have a tach and temp gauge already, and oil is easy enough.

    The unibodies are very similar on XJ/ZJ.

    Vibration isnt a concern honestly.


    I appreciate your input.

    Seems like the mech pump will be the way to go. With doing that, can I simply remove the in tank pump? Then just use a sock and in line filter? Good to hear that the trans mount should pretty well sort itself out. Im thinking cut apart the stock mounts and using a piece of tube if needed to adjust the height. Thanks for your input as well.
     
  5. Jody Treadway

    Jody Treadway Croc wearing fool Moderator

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    You should be able to use the old pump as a source of getting the fuel from the tank to the lines, but not as a pump. You'll blow the carb apart in rapid fashion.
    AMC motor mounts are easy to make frame mounts for. I've swapped 360s into 2 Jeeps now using simple plate bent to match the profile of the stock Waggy motor mounts.
     
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  6. JSJJ388

    JSJJ388 GREEN GREMLIN

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    Good to hear.
     
  7. upnover

    upnover Grumpy, decrepit Old Man Moderator

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    For the engine mount I use the easy peezy Piece of heavy walled tube. Get tube that a poly leaf spring bushing will fit snug into, Tabs on the frame, single bolt through the tab, into the bushing, and out of the other tab. Make sure you get a bolt that will fit snig inside the tube. On the engine side, cut a plate to bolt into the 360 block, Piece of tube to span from the frame mount, to the plate. Angle on engine side, and cut to fit the tube with the bushings. Tack it in, remove, weld it up, and install it. Repeat this for the other side. Seen many done this way. As long as you use good tubing and your welds are good, it's hold all the 360 can torque!

    I second (or 3rd) the mechanical pump. Not sure if the existing pump/sending unit will allow fuel to be pulled through or not though.

    If you are going to use it off road and make a skid plate, I'd make the trans mount pretty much like the engine mount. That way you can drop the skid if you need to, and not have to support the trans and t case.

    Wire in alternator into factory harness, a switched hot wire for the coil, and you "should be good to go"
     
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  8. JSJJ388

    JSJJ388 GREEN GREMLIN

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    That seems like a good way to go as well for the mounts.

    Hoping to reuse the factory skids. Have engine, tranny/tcase, and fuel tank from factory.

    You mention the alternator. That brings up a good question. Looks like I may have to buy a new alternator and specify the 94 amp one. The 360 one is internally regulated and the 4.0 is external. Is this going to cause a problem? I would assume itll just be double safe?
     
  9. Jody Treadway

    Jody Treadway Croc wearing fool Moderator

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    You won't be controlling charging system outout with the PCM any longer. Wire up the alt the same way it was when AMC ran the show.
     
  10. JSJJ388

    JSJJ388 GREEN GREMLIN

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    Gotcha. You guys are great.
     
  11. upnover

    upnover Grumpy, decrepit Old Man Moderator

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    Not a problem. Send each of us your address so we know where to send the consultation bill LOL

    Just kidding, many here are happy to help.
     
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  12. JSJJ388

    JSJJ388 GREEN GREMLIN

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    I got two jeeps man and a new kid, Im B-R-O-K-E
     
  13. Scooter402

    Scooter402 Rest in pieces

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    If you try pulling fuel through the stock in-tank pump, you'll have fuel starvation issues at speed (if not even at idle). When I swapped a 350 into my old YJ, I ended up having to pull the stock pump out of the tank. All I had to do was add a piece of tube in its place so the pickup stayed down in the bottom of the tank. Nothing fancy, just used hose as a coupler and clamped it in place. The sending unit worked fine because I got an aftermarket gauge that matched the resistance range of the stock unit. The factory gauge setup had to go obviously since it was ran by the ECM.
     
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  14. justjeepin86

    justjeepin86 Well-Known Member

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    What year is your ZJ? Will you have any inspection problems? Assuming it will be road driven.

    Sent from my SM-J737A using Tapatalk
     
  15. JSJJ388

    JSJJ388 GREEN GREMLIN

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    94. And no, we just have safety inspections in Yadkin county, which is great.
     
  16. a_kelley

    a_kelley mechanical fixer

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    Well if you want to be technical, it's supposed to be that year or newer donor engine to satisfy federal emission requirements.. and technically, they still are supposed to visually confirm all emissions equipment that it shipped with are present - even on safety inspection.
     
  17. JSJJ388

    JSJJ388 GREEN GREMLIN

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    Nerd. Lol. I'm sure my jeep already breaks all the emissions laws and a plethora of other rules. I guess I could just say I put a 5.9 in it, since it is 5.9 L.and that was an option on the ZJ.

    Sent from my SM-G930T using Tapatalk
     
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  18. a_kelley

    a_kelley mechanical fixer

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    Hey I'd put the old 360 in but also swap in the fuel injection stuff but that's me... Sure carbs are simple but so is factory EFI!
     
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  19. JSJJ388

    JSJJ388 GREEN GREMLIN

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    Ok, Im listening... How hard and expensive would fuel injection be? Bearing in mind that I am having computer problems already in the ZJ.
     
  20. Scooter402

    Scooter402 Rest in pieces

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    How hard? Well...it's so easy, even I can do it. Got a wrench and some time? That's about all it takes (and a wee bit of intuition). How expensive? Well...that one depends on how fancy you want to get. You can very easily swap a GM TBI unit on it. There's stores on eBay that sell it as a complete (plug-and-play) kit, ECM and all. I don't know how it acts on a 360, but I'm sure it couldn't be too terribly different than how it would be on a 350. Especially if your engine is stock. You could also get all the parts from a junkyard, but there's never any guarantee for how well/long they'll work.
     
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  21. JSJJ388

    JSJJ388 GREEN GREMLIN

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    Hmmm.... Ill have to simmer on that one. Was planning on leaving the carb as is for simplicity sake, and of course because a tight wad. Ill look into it a little further.
     
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  22. Jody Treadway

    Jody Treadway Croc wearing fool Moderator

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    Listen here you commie bastid, don't disgrace an AMC by calling it something metric.
    God himself calls them 290, 304, 360, 390 and 401s.
    Better you hear this from me before @amcjeepman sees this!
     
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  23. JSJJ388

    JSJJ388 GREEN GREMLIN

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    :D:D:D
     
  24. Scooter402

    Scooter402 Rest in pieces

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    I know all about leaving the wallet clamped in a vice...just ask @Croatan_Kid... he'll tell you how cheap I am. :lol:
     
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  25. amcjeepman

    amcjeepman Si Vis Pacem, Para Bellum Moderator

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    :D
    I don't have anything to add other than to mention you missed the 343.
     

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