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Projext "V8 XJ" Build

I just finished my swap a few months ago. Check out my thread here:
http://www.naxja.org/forum/showthread.php?t=1119575

1. The wiring is NOT difficult unless you have no idea how electricity works. There is one BIG caveat to the wiring that no one mentions. If you're wiring up the OBD port, it MUST get it's power from the same wire that powers the ECU. No, just because it all comes from the same battery, does not mean you can just splice in anywhere. Splice it in within a foot or two of the ECU power. If you don't, your OBD will be wonky as all hell and you'll want to kill yourself and your whole family. Ask me how I know.
Otherwise, the wiring is very easy. The Chevy harness side is insanely simple. I'd suggest, now that I've done it, just use the stock chevy harness with the bare minimum modifications required to get it into the Jeep to start. Worry about re-working the harness once the motor and everything else have been proven. Trust me on this. It'll make your life much easier.
The Jeep firewall side of the wiring is the hardest part, only because most of your wires will be stuck together and the colors faded. Find an FSM, have it in hand. Honestly, the hardest part of this swap was dealing with Jeep wiring, and even then, it wasn't hard. I'm ****ing terrible at wiring compared to my roomies because I'm too lazy and impatient, and this still wasn't a big deal for me. Don't let everyone else scare you here. You don't need a painless harness, especially because the bulk of the wiring job is on the Jeep side.

2. Novak motor mounts suck.

3. Lots of guys say the stock A/C compressor won't fit between the motor and frame rail.

4. Don't bother with the 4.8. The 5.3 will net you between 17 and 26mpg depending on your aerodynamic profile. My heep is the poster child for all that can go wrong with aerodynamics, and I get 17-18mpg on the highway. That's pushing 35x12.5 shoes, 6.5" lift, full size roof basket with 52" light bar. On a more stockish XJ, I'd expect at least 22-23mpg from the 5.3, and my god is it fast. I drag race EVERYONE now, and I no longer do it just for the sake of being ironic. I win often.
The 6.0L I feel is overboard, but I've heard that it'll give very respectable fuel economy as well, in which case I feel like it's one of those "if it's a toss up between the 5.3 and 6.0L fo the same price, go with the 6.0L" things.

6. The AA t-case>trans adapter sucks at sealing. The trans side might seal, the middle section with the o-ring will not, nor will the t-case side with their paper gasket. Make liberal use of RTV everywhere including the o-ring. For the t-case side, you should probably just make a new gasket and RTV the hell out of it. The stock t-case studs are barely long enough to grab the nuts with a paper gasket, assuming you're using the AA mount as well. The whole thing sucks but it's doable. You may have to pull the case several times to re-seal until you get it right.

7. I'd go with a 241/241 hybrid. You can find the long input, wide bearing 241 input gear and planetary assembly from most chevy 241's. It'll drop right into your 231 case. Don't forget to swap in the WIDE BEARING on the input side if you have a wide input gear. VERY different clearances and the narrow bearing with the wide/long input gear, will have the planetaries eating the front of your case off. Also remember that the 231/241 planetaries and ring gear have two different cuts. Something like pre and post 96. The earlier were a courser cut while the later were finer. They will intermix but they will be very whiney. I used an np241c input, np231 main with sye, np241 chain and chain drive.

8. T-case shift linkage.

9. Trans linkage. Use an XJ auto shifter.

10. Radiator. The 3 row CSF scares me a bit as the tubes are very small and easy to clog. You mileage may vary. I went with a Griffin 22x19" and made it fit by cutting out the lower rad support. Keeps me VERY cold with a taurus fan behind it. Again, I'm not the right guy for this either as lots of guys have stock size xj rads doing just fine. My way worked though as well.

Feel free to toss any questions my way as well. I feel like I could do this swap the second time in a solid weekend. It's really not that bad if you aren't a tard, and/or not wildly drunk :p.

1. I have done two harnesses and both had OBDII port power coming in separate from the ECU without issues. I'm not sure why yours was being fussy, but good you figured it out.

2. I made my own, but it was out of necessity. Novak didn't have the mounts available when I did mine, but it wasn't hard to make them.

3. I never heard anyone say that before and mine fit fine. I have about 1/2" clearance to the frame.

4. I would definitely save a little longer and go 6.0L next time. I get about 10MPG or less, but I also drive it like I put a V8 in my Jeep. Aside of maybe one tank where you try really hard to see how high of gas mileage you can get, the MPG argument is a silly one.

6. I didn't have an issue with sealing, but I did use a liberal dose of RTV to start with.

7. In hindsight, I would definitely go with a 241C before the AA adapter/231J again.

8. I used a Novak t-case shifter and it worked really well.

9. I did this and hated it. On road, WOT and looking for 2nd gear sucks.

10. I couldn't get mine to cool either and ended up with a really expensive Be Cool radiator. It was the only solution that would work for some reason. It made me nuts because I have a buddy running a 130k mile stock radiator on his LS swap and it's fine.

Glad you got yours going and your happy.
 
Engine is OUT! I only forgot to disconnect one thing, the transmission selector cable. It super hard to see anyway.

I'm not posting many pictures of disassembly because it's very straight forward.






Realized that I forgot to drain the transmission fluid and engine oil. Took off the transfer case to make this mess...
 
Care to explain why? Other than the fact that its bolt on. What would you do for the Jeep Speedo (I know you ran aftermarket gauges)?

Cheaper, by a lot. As far as gauges, looking back from what I have now with the Autometer's I wouldn't consider running a stock cluster. The Autometer's look better than I expected and they are accurate.
 
Okay, here's the problem with sticking a chevy t-case behind the 5.3 or 6.0L, in a Jeep.
SYE availability.

Yes you can bolt an np231/241c behind almost any chevy transmission, auto or manual, and yes you'd get the 40 tooth speedo reluctor from the chevy case. All is well at this point except that no one makes an SYE for the chevy cases. This makes things difficult for most of us, as we need it to accommodate our lifts.

Yes, jbconversions claims to makes one, but try to buy one and you'll understand. Their website lists all the chevy SYE's as out of stock, they don't respond to emails and they don't answer their phone. I spent 3 months calling and emailing, trying to figure out when they'd have their C SYE's available. After a month I finally got through to someone and they told me the C kits would be in stock in 2 weeks. 2 weeks later, still out of stock on the website and I spent another month calling before someone answered, and apparently the kits were still a month out. 3 months later, when I was ready to start ordering parts for my build, they still didn't have the kits available and the ETA was perpetually a month out.

This is why everyone adapts a Jeep case to the chevy motor.

That said, I see now, after 8 months, jbconversions doesn't list the kits as out of stock, so maybe it's an option once again. This would be sweet as it'd save us a few hundred bucks as you're getting the SYE and the speedo all in one package for about the same price as just the j adapter and speedo (minus the SYE that you'll have to supply).

I went with an NP241c wide bearing long input (new cut), NP231j case, NP231c chain, sprocket, and front output, and NP231j SYE main shaft. I already had several full NP231j's lying around (with an SYE), so I just needed the 241c input, chain, sprocket and front output. I couldn't find a complete 241c at the wrecker so I grabbed a complete 231c for $50, and on my way out, I found a 241c input just lying on the ground :) Wrecker didn't know what it was so I got it for $5. Total hybrid case build cost me $65 or $70. Took me about an hour to assemble (my first attempt at taking apart and putting back together a case). It's really not a difficult job.
 
This is what the engine bay looked like after yesterday
0D7009E2-BCA6-4DD6-9F34-6500E465149E_zps8kt6cvvc.jpg
 
Where you goona put your ecu? Word of advice, figure that out before putting the motor in. Rework the Chevy harness on the motor out of the truck.

I just spent nearly 2 full days doing mine in the truck and it was the suck. Next one I do will be fully wired before I even pull the 4L.
 
I would say a D300 would work quite well. Or maybe a doubler with a chevy front case and a D300 behind it?
 
Where you goona put your ecu? Word of advice, figure that out before putting the motor in. Rework the Chevy harness on the motor out of the truck.

I just spent nearly 2 full days doing mine in the truck and it was the suck. Next one I do will be fully wired before I even pull the 4L.

ECU is going to be mounted in the same location as the Jeep ECU. I plan on sending out the harness to be reworked. I really don't want to do it. And its only $250 for 150tunes.com to do it.
 
Where you goona put your ecu? Word of advice, figure that out before putting the motor in. Rework the Chevy harness on the motor out of the truck.

I just spent nearly 2 full days doing mine in the truck and it was the suck. Next one I do will be fully wired before I even pull the 4L.

I took a big piece of cardboard and drew the engine bay, engine and all sensors. Then used it to build the harness on my living room floor with my kids. It was easy, fun and a perfect fit when I went to put it in. Wiring it in the car would really suck.
 
So I have a question.

I'm having a hard time understanding the wiring diagrams. I'm pretty sure I'm correct in this, but I just want to check.

The DG/OR wire that is power to the injectors and ignition coil crosses over connector C107. Can I just terminate the wire at that connector? Or do I need to terminate the power at the splice?
 
Yup. You want to self contain things as much as possible. I grabbed an ignition from the jeep and that's the only stock power I used. I grabbed some snap together relays, mounted them on the firewall, and ran all the Chevy power from there. You'll need extra relays anyway for your tcc lockup to brake switch anyway.
You really don't want any of the stock Jeep wiring powering anything in the chevy motor. The only wires I ended up using from the Jeep are for ignition > ECU, brake light switch > TCC relay > ECU, crank signal > ECU, OBD power/ground/serial > ECU, and... I think that's about it. All the power goes through 4 new relays on the firewall. One for fuel pump (though I could've used the stock Jeep one), injectors/coils, TCC switch, O2 sensors, and I think that was it.
I ended up with three plugs from the Jeep to the chevy harness. 2x4pin connectors for all the power stuff, and 1x8pin for all the non-power stuff. By the time you're done, you want to be able to disconnect your engine harness and drop it into any other Jeep with a few splices to add plug ends to the Jeep side.

The DG/OR is only 20A fused which may not be big enough for all the chevy power stuff. There should be a spare 40A fuse in the PDC you can use instead to power a few relays (on the firewall) for chevy stuff.
 
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I would take it all the back to the PDC, then use the circuit for something else or as a spare for the future. It's a 20a circuit. I did this with several of my unused Jeep circuits.

That specific circuit I cant take back to the PDC as it supplys the PCM with power. I'll take as many of the connections back to the PDC if possible though.
 
Harness is mostly complete. I have to splice some connections. And remove some wires from connectors. I don't have the really helpful each tools and busted a bunch of the retainers in the black PCM connector. Oops. It'll still work.

You end up removing 13 connectors from the engine harness. I haven't touched the C3 PCM connector as its part of the body harness. I will eventually, but not right now.

This is the harness. All that remains is the Coolant temp sensor, oil pressure sensor, speed sensor, and the TC gear selector light.(debating wether I'm going to remove this)
AB232B98-2F7B-447E-9FB1-C380CFFC5B70_zpsmulguwbz.jpg


Wires removed
96FF65E3-7399-44C3-B9AF-D97CF0D3EA9D_zpsugvntmas.jpg
 
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