What should I do with my 86 LWB?

[DirtyComanche]

As some of you may know, I have an 86 LWB 2wd MJ out behind my buddy's barn, and it's umm, seen better days.  There is no engine, trans, or tcase in it, along with minimal chassis wiring, the interior is rather messed up, and well, a large tree fell on the box.  Otherwise it's practically mint, if you don't mind the high school paint job and the few holes in the rockers, and maybe the floor, and well, anyways, yeah, it's practically mint!

 

I would like to build it into something of a driver/wheeling rig to do one very specific thing, which involves driving it slightly over 1000 miles on a mixture of paved and gravel highway, fueling up, then driving 130 miles of mountainous gravel sideroad, then approximately 200 miles of actually wheeling the old trail (which is a mixture of easy stuff, with harder stuff and water crossings thrown in), then driving the 130 miles back down the gravel sideroad to where there is again fuel.

 

With this in mind, it is somewhat of a blank slate for a driveline install, since it doesn't have one.  So, please help me decide.

 

I will likely purchase a NWF EcoBox and rebuild a Ford NP205 that's sorta in my possession for the reduction/tcase.  I am already running one of these setups and I do like it.

 

Option #1 - Renix 4.0L and an AX-15. 

 

Reason being, I happen to have one sitting on the floor of my shop (was waiting for the ground to freeze to move it to the shed).  I've also got the harness and ECM for it, plus an entire XJ chassis harness that goes with it.

 

Pros

-I have it

-It's cheap (free)

-I have a lot of spare parts for the Renix system

 

Cons

-It won't fit the chassis without modding the firewall and rad support

-It's somewhat history unknown, I know it drove

-AX-15 is internal slave, and I would wind up spending money on changing that either way

-Fuel economy and power might be less than excellent

 

Option #2 - 4.0L HO and AW4

 

For this I would just buy a 97+ XJ and steal the parts I need.

 

Pros

-Wouldn't be too expensive, a whole donor rig could be had for $2000 or less, and I would probably find a use for many of the other parts off the donor

-I could drive the donor vehicle for a week or two to ensure things are 'okay' prior to proceeding

-Needed bits for the rad support, and many other needed items would be included in the donor, saving time and money tracking down small pieces

-Makes some more power than the Renix

-I prefer wheeling a slushbox automatic for the most part

 

Cons

-I'm not too familiar with the HO or wiring

-I do not have any HO specific spare parts

-I would probably have to swap the dash in? I kinda prefer the old style dash and have a good spare in my shed

-I would have to admit to Hornbrod that I own a HO and like it

-Would require catalytic converters, or simulators for the rear O2 sensor

-Fuel economy might be worse than a modded Renix

 

Option #3 - VW TDI (ALH) and NV3550 (or external slave AX-15)

 

I would buy a Jetta as a parts donor for this

 

Pros

-Fuel economy would be much better

-Lighter

-Fits nicely in the engine bay if done right

-Diesel torque along with the ECM's desire to not stall the engine makes for less dancing the pedals with a manual trans

 

Cons

-Costly between the cost of a good donor ($3000, some could be recouped selling parts), a good used NV3550 ($600), adapter/remote filter/mounts ($1800)

-Lots of time (and other small costs) making "all the little things" work

-I've never owned a VW, not sure I look good in Lederhosen

-Out of the box the power level will probably be lackluster....  $$$ and time to make more power reliably.

-I have zero spare anything for this and would need to hunt down some stuff

 

Option #4 - Swap a MPFI 2.5L and automatic in

 

I don't know how a guy would go about this decently...  But the chassis was a 2.5L truck, so that's a start???  I'm guessing look for an elusive 2.5L later model XJ that's not bagged to steal one from?

 

Pros

-Lighter

-Maybe better fuel economy by a bit

-No real mods required to the engine bay

 

Cons

-Lack of power

-I don't think any of my spare parts fit (there is some 4L/2.5L interchange)

-I don't even know what automatic transmission to bolt to it, and is actually reliable, and I need OD and lockup for fuel economy, and a 23 spline output since I have no 21 spline later cut input gears to put in an Ecobox

 

Option #5 - Something else.

 

There's probably a better idea out there, I just don't know what it is.  If so, do tell me.

[Ωhm]

Put that pile of Renix stuff you got to work for you.

[Dzimm]

I say renix since you got it, HO if you want to.  The other ones seem very complicated and time consuming.  I feel with the combination of all the work the truck needs plus a major Drivetrain swap, you may get burnt out on the truck.  On the other hand, it would be pretty sweet with a drivetrain swap like you describe. 

[DirtyComanche]

1 hour ago, Dzimm said:

I say renix since you got it, HO if you want to.  The other ones seem very complicated and time consuming.  I feel with the combination of all the work the truck needs plus a major Drivetrain swap, you may get burnt out on the truck.  On the other hand, it would be pretty sweet with a drivetrain swap like you describe. 

 

The truck needs exactly one of everything, so burnout is highly possible.  That said, I actually find it easier to start from zero rather than to deal with the compounded issues that happen when you assume the prior work was done right.  The build thread for my SWB is lacking pictures, but it fairly clearly illustrates how much time was lost because I had assumed that things were done correctly by the PO.  It would have been faster to dump a driveline I'd built up out of the truck into it, and I do regret not just doing that.

[DirtyComanche]

2 hours ago, Ωhm said:

Put that pile of Renix stuff you got to work for you.

 

Tempting, and easiest, I think.  Massage the firewall, throw a 4L front crossmember and rad support in, string the wire and that's it???

[HOrnbrod]

I voted "Something else". 4.0L HO and AW4 is the best option, but not an OBD2. You could p/u a 95 or below XJ and do the same as you could with an OBD2 XJ for probably less $$. OBD1 is simpler to work on, replacement and go fast parts are still fairly plentiful; can't see any advantage going OBD2. I've had several, and prefer OBD1.

 

And yes, you'll like it better. 

[DirtyComanche]

1 hour ago, HOrnbrod said:

I voted "Something else". 4.0L HO and AW4 is the best option, but not an OBD2. You could p/u a 95 or below XJ and do the same as you could with an OBD2 XJ for probably less $$. OBD1 is simpler to work on, replacement and go fast parts are still fairly plentiful; can't see any advantage going OBD2. I've had several, and prefer OBD1.

 

And yes, you'll like it better. 

 

I debated getting one, there's a 92 XJ with an alleged rebuilt engine and trans for $1500 here.  But I was going to probably throw the Renix controls on the HO engine if I did...  Part of my reason for wanting to get a 97+ is I think I'd like to throw the sheetmetal/doors on my 88 at some point, plus they come with a plastic gas tank, which might work for something down the road.

 

If you're going to buy junk you gotta buy junk you can use.

[HOrnbrod]

Makes sense Dirty.

[87Warrior]

I do believe the 2.5 MPFI would be the easiest option followed closely by the 4.0 OBDI/II and AW4 option which would be the next easiest and most reliable option.

Although....I have lusted after a 5.3 powered MJ for many years....

I didn't vote since I can't make up my mind!

 

[DirtyComanche]

6 hours ago, 87Warrior said:

I do believe the 2.5 MPFI would be the easiest option followed closely by the 4.0 OBDI/II and AW4 option which would be the next easiest and most reliable option.

Although....I have lusted after a 5.3 powered MJ for many years....

I didn't vote since I can't make up my mind!

 

 

I looked at the 4.8 and 5.3 option and a couple things turned me off, but maybe I should rethink it?  In order to get a truck motor (which are the cheap/available ones) to clear the hood you need a LS1 or LS6 intake manifold, fuel rails, and injectors, which costs a few bucks.  You also need an accessory drive bracket kit ($300) and an LS1 water pump.  It's also a bit of an unknown (perhaps if I did more research) if any of the cheaper stainless headers would fit, the idea of buying some crap plain steel headers from Novak for $400 churned my stomach.  Then you have to fix a Y pipe in because there certainly won't be space for true dual exhaust, but I'm sure that can be solved easily enough.  Then you have to shoe horn a radiator in there, although I've seen some good options.  And then you're stuck deciding what GM transmission to use.  4L60E? 4L80E? 6L80E? NV3500? NV4500?  I actually have a NV4500 hanging around here, but it's slated for another project, and it would require floor butchery (totally okay with that).  The NV3500 isn't known to hold up amazing behind the 5.3, but it is factory behind the 4.8L, but it's a fairly rare combo to find a donor.  It would be easy enough to get one of the automatics in there though.  And lastly, you'll need a good programmer (EFI Live) or to spend bucks sending the ECU out; the VW swap would also require this.

 

I think the 4.8 would get better fuel economy than the 4.0L...  It is a very efficient engine design.