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1991 MJ build thoughts: 2wd->4wd, lift?

93xjcowboy said:
If you do that you wont be scraping everything on everything like you were during Roktoberfest.
Click to expand...
I'd be insane to run 230lb 46" tires on a 44. Maybe a beefed up 60. That pic was a joke though, those tires are going on the 5 ton.

Once I put the new frame on this thing, it won't matter if I scrape on everything :D
 
kastein said:
I'd be insane to run 230lb 46" tires on a 44. Maybe a beefed up 60. That pic was a joke though, those tires are going on the 5 ton.

Once I put the new frame on this thing, it won't matter if I scrape on everything :D
Click to expand...

Youll be fine the 44 is a bulletproof axle. Only idiots break them.



Yes Im joking..... A beefed up 60 would be begging for mercy with those tires.
 
well

long story short, things have changed again!

I have been fixing and breaking minor things for a while now, it wheels decently and has front and rear recovery points now. Rear bumper looks just like the front one - 2x6 box tube, 1/4 plate mounts, 1" plate D-ring mounts that go through the bumper and are attached to the mounts directly for strength.

I took it to WinterFest on a tow dolly and spent most of my time watching my welding helmet and cutoff discs blow across the campground, with some fabrication and repairs mixed in. I even got a half day of wheeling done, and mildly hydrolocked it coming out of the tubes. Still runs great, but I need to do a rebuild on the motor for peace of mind, I suspect at least two conrods are tweaked.

Also, the 5.2 that I accidentally bought (I was told it was a 5.9) is definitely going in this now, because I picked up an NV3500 with all the stuff to bolt it to a 5.2 today at the junkyard for $140. A 23 spline 231 will bolt right up to the other end... I have one I will be installing an SYE in.

Still undecided on the axles, probably going with the 8 lug 44/60 though, I now have 2 sets of 16" wheels for 8 lug axles, one came with my budget tow rig and the other with the 5.9 donor for the other MJ. I'm not sure if I really want to run a front 44 with a 5.2 and my right foot on one side and 35s on the other... still need to make that call.

Haven't decided if it's getting a late model interior or staying 96- style, either. The ECU I have for the 5.2 is a 98, so I'm definitely going to pass the CCD bus through the harness to the interior just in case I want to do the interior swap in the future (if I don't do it immediately.) I'll probably end up with the 95 steering column off Travis' old green XJ in this turd if I don't swap to the late model interior, simply because the stock 94- GM column is kinda jacked up and worn out and I have it sitting around.

I have patched the worst of the frame damage and it will hold together fine but I still plan on the full frame - especially since I'll need to do custom motor mounts and suspension mounts for the new stuff anyways. Yes, I'm stupid, don't bother telling me that.

I even had a license plate light on it (for the first time since about a year ago) for a grand total of 3 days before I backed up into a stump and demolished it again. I guess I will put a 1/4 plate guard frame around it when I replace it.

EDIT: super awesome trivia time. The pilot bearing + bushing kit that I need to put the NV3500 behind the (originally from an automatic vehicle) 5.2 I have is part number FC69907. Guess what that also fits? Most stock XJs with AX15s. I have one brand new in box in my spare parts stash... time to go start putting my new drivetrain together!

I can't believe I am putting a different motor and a different transmission in, and yet still using the same exact pilot bearing.
 
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Between the two projects, I have 3 ECUs. I may need others, this is sorta a note for myself and sorta helpful for anyone who is trying to do the swap...

1 - 5.9 '94 Ram 2500 MT ECU
2 - 5.2 '98 Ram 1500 AT ECU
3 - 5.9 '98 ZJ ECU

Some tach signal info:
91 MJ tach signal specs (I4, I6):
66.67Hz = 2000rpm +/- 140rpm
166.67Hz = 5000rpm +/- 140rpm

94 Dodge Ram tach signal specs (V6, V8, Diesel):
100Hz = 3000rpm +/- 200rpm

MJ:
66.67Hz / 2000rpm = 33.3 Hz / 1k rpm +/- 70 rpm / 1k rpm

Dodge Ram:
100Hz / 3000rpm = 33.3 Hz / 1k rpm +/- 66.67 rpm / 1k rpm

The only difference is a very minor (probably imperceivable) tolerance difference.

What this means is that an ECU from a Ram that was built before the instrument cluster was changed to CCD driven (reportedly the first year for CCD Ram clusters is 98, I want to check a 97 and a 96 at the JY in a few days just to really nail this info down) provides *exactly* the same tach signal frequency as a pre-97 XJ instrument cluster receives, i.e. you can simply wire the tach output signal on a suitable year Ram ECU right to the tach input signal on your old body style XJ instrument cluster. That almost seems too easy. The battery gauge, fuel gauge, temp gauge, oil pressure gauge, and all indicator lamps are individually wired to their own sensors/senders so they present no problem for an engine swap either.

Based on this I think I'm going to build an OBD-1 harness for this MJ that plugs right into the stock bulkhead connector, and keep the '98 5.2 ECU until I feel like swapping to a late model interior, then redo the wiring for it. I will either use the '98 5.9 ZJ ECU for the other MJ project or sell it for enough to cover the costs of buying a '98 2500 5.9LD MT ECU. Not sure what's going to happen to the '94 5.9LD 2500 MT ECU, probably resell it to cover some of the costs of buying the drivetrain donor.
 
I doubt you're going to put too much more of a hurting on a D44 than a 4.0.

I'd say it should survive decently on 35s.

I love Chrysler for parts interchangeability.

It's no coincidence that the input shaft length and diameter where the pilot bushing rides have not changed in like 40 years :laugh:
 
Comparing the alloy 44 outers I bought off Tim at chickenfest to a 30 outer I have sitting here, you are probably correct (the yoke ears are significantly thicker, I always break those not the ujoint.) I just know I can break 30 yoke ears off on command with 33" ATs, and don't really want to make that worse on 35" MTs.
 
For anyone who is doing a 318/NV3500 swap and got the trans and motor separately and has to buy the locating dowels, they are not the same as XJ ones, unfortunately. At least for a Chrysler 318 (mine is a '98, my trans is out of a '99, they are the same per dealer parts counter discussions) you want locating dowels part number 1122532. A few bucks each.
 
well, the full frame is happening. Because I just bought about 200 bucks in metal for it... doing the back end first. I'm using 2x5 1/4 wall for the frame rails under the bed, 2x4 1/4 wall to build the crossmember(s) under the bed, 3x4 1/8 wall for the shackle hangars (may have to change this or gusset it, but it's slightly thicker than stock and I've had zero problems), and probably 2x4 or 2x5 1/4 wall for the frame under the cab and nose. Since the floors are gone, it's getting a 318, nv3500, rock rails, and 3/4 ton axles with a 3 link the only thing really keeping me on the stock frame is the firewall, back cab wall, and leaf spring mounts, which isn't enough of a reason to me. Hopefully with the 1/4 wall frame I can push the front frame rails out a little wider under the firewall and make it even easier to fit the smallblock stock exhaust headers.

By my calculations the frame should weigh approx. 400-500lbs including rock rails and will cost around $550 in materials.

I will probably end up building custom bucket seat mounts for it since my floors won't be factory anymore, which means I don't need to waste Billy's time swapping seat mounts out of my other MJ if we trade, too... that only makes trading more likely.

My ugly but strong front and rear bumpers will probably end up being sold too, no reason to keep the stock bumper mounting style when I can improve/simplify it.
 
Subscribed ken.

I hope you get both of you MJs done. I have a 5.9 and tranny that's in a beast of a '91 2500 that one day(not anytime soon) will live in a jeep. either mine or my dads MJ. and Ill be looking to your threads for instruction.
 
I hope so too :eyes:

Biggest problem looks like firewall and shifter linkage interference. The nv4500 shifter tower is several inches further forward than the ax15 one, the v8 is also of course shorter and wider, which means either moving it forward or bashing in the firewall. These are gonna cause problems on the 5.9 mj when I try to put the 97+ interior in and make it look factory but likely wont cause any problems on the 91 where the floor and such will be non oem anyways.
 
Sold the balljoint 60 I briefly considered putting in this, bought a mid 80s kingpin 60 for 100 less than I sold it for. Also buying a 231-231 doubler kit from a friend of mine... once I take a few more measurements, I'm going to hit the steel yard tomorrow and get the rest of the metal for the frame.

Then it's game on.
 
Well I have a wheeling trip this Sunday/Monday and I need to make it pass inspection before then to avoid a ticket on my way there. I have to fix:
- parking brakes
- windshield
- fender flares
- maybe pinion angle and/or transfer case skid, new driveshaft
- rocker panel rust

I mounted a stock horn in a super awesome position because my original one was dead from having a 33" AT stuffed into it too many times. Other than that I haven't done shit to it... except I made it into a crane today :gee:
461497_631321385012_29101008_32225671_906317844_o.jpg


Looks like tomorrow I have to get a lot of stuff done, then finish things up Friday morning if I'm not done with it and go get a sticker.

Parking brakes I just need some ubolts to loop the cable around the disc brake ebrake lever.

Windshield is gonna be a disaster, but I'm doing it myself. I have two passable windshields sitting here waiting to go in.

Fender flares I am going to make with $25 in galvanized sheetmetal and EMT. I don't really care what they look like as long as they pass. Flatfender and zinc flu here I come.

pinion angle / transfer case skid / driveshaft is optional and happening last.

Rocker panel repairs will involve either mass quantities of duct tape, or pop rivets and more galvanized sheetmetal. It'll all get ripped off soon anyways to do 2x6 rocker replacements and the new frame so I don't really care what it looks like as long as it passes.
 
I have been avoiding washing it for a while :thumbup:
 
Put a junkyard windshield in it, hack fabbed everything else together, GOT AN INSPECTION STICKER!!! :shocked:

windshield is broken now (and has been since unibody flex / thermal stress killed it at NACFest) but I have a sticker, so I can get a new one whenever I want for free.

All I need to get before I can start on the swapping is the new radiator (need to put it together before I get that...), some tube, some box tube, probably some coilovers for the front, and whatever tires I decide to run. Too bad I'm broke.
 
There ain't no such thing as a free lunch... we pay out the ass for insurance, and get glass coverage. At least I have it.
 
I had it up to 80 today... lacking a 1920s style helmet and goggles, glass is something I really approve of!
 
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