I think I am gonna build an Unlimited....

Metcalf

Metcalf

Expedition Leader
kodiak,

Its hard to really know what kind of mileage the project is going to get. The only other diesel LJ I have knowledge of is the development jeep AEV built. They swapped in the 2.8L liberty CRD and the 5 speed automatic. This is a quote from there website...

Fuel mileage is excellent with it hovering around the 19.5-20.5 MPG mark with the top off at 75 MPH. Off road, the diesel tends to use about half as much fuel as the 4.0 or 5.7 vehicles normally traveling with it. Power is somewhere in between the 4.0 and 5.7.

This jeep was built very similar to how I want my jeep. I have talked with Dave, the owner of AEV, about the swap in detail. My impression is that he is VERY happy with this combo. Here is some video with the diesel jeep making an appearance.

http://www.youtube.com/watch?v=RXmDsnxk-M0

http://www.youtube.com/watch?v=IbEIWfLDM6Q

My setup will be slightly different. I am planning on running a 2.8L mechanically injected diesel engine and manual transmission. I would love to see 25mpg! I think with some proper tuning and gearing this might be possible if I keep the jeep as light as possible, low to the ground, and not run too aggressive a tire.
 
WJinTRSC

WJinTRSC

Adventurer
Sounds great! I can't wait to see what engine you end up going with. I'm still learning here, so pardon my ignorance, but why is it a bad thing for the turbo to be on one side or the other?
I personally would like to stay with an automatic if I do a diesel swap, just cuz I've already got an A/T in the WJ and less to redo inside. W/ this type of veh. as a DD, it's just convenient, but there are times, going downhill that I really wish I had the better gear reduction of a manual to hold me back and give me more control like I used to in my old truck. I wish they'd just program the computer differently so that the tranny just won't let it rev too high when you're off the gas while the jeep's in 4Lo.
 
Metcalf

Metcalf

Expedition Leader
The turbo placement is purely for clean packaging. A passenger side turbo lets you run the exhaust right down the passenger frame rail without having to cross it under the oil pan or transmission like the stock jeep 4.0. There is also a lot of stuff on the drivers side ( at least in the LHD/USA ) like the brake booster, master cylinder, steering column, etc. The factory air cleaner is also on the passenger side....or more room for an after market system.

I am also going to have to package in an inter-cooler that will have to be about the same general size as the factory jeep radiator. I am hoping that with the shorter diesel engine I can space that radiator back enough to fit the new inter-cooler in between the factory grill shell and factory radiator position ( in essence just stacking the both together ) I am going to have to change the radiator anyways. The outlets are in the totally wrong place for me. I think an upgrade to the factory TJ plastic tank radiator isn't a bad thing anyways.

Either a passenger or drivers side turbo can be done. I am just taking as easy as a path as I can.....I think.

Automatic transmission.....

I have thought about it. I have owned both. I had a wonderful early TJ with the auto and loved it. It was a very good combo overall. In general however I rarely find an automatic transmission that I like. Most have terrible shifting characteristics for me. They always seem to shift at the wrong times or not enough or hunt between gears a lot. For me a manual transmission means that I am responsible for how the transmission shifts. I can't use the 'its the transmissions fault' excuse. I did have an interesting talk with one of the Curries once. He brought up the very good point that with an automatic you don't have to worry about killing it. You can use the brakes whenever and however you want without stalling it. Starting and stopping on hills is generally a lot easier as it the ability to power into and out of some situations.

If I end up making the stock jeep 6-speed work for this swap any transmission that was behind the 4.0 should also be feasible with the correct flex plate. Also any GM automatic would be fairly easy to make work. This opens up a lot of options for those people to are thinking about an automatic.
 
WJinTRSC

WJinTRSC

Adventurer
has anyone considered doing some modifications to the hood and making your own custom "scoop" to make a place for the inner-cooler or help w/ intake/cooling/ventilation in other ways? If you get creative w/ this, maybe you could come up w/ some interesting methods of doing it. Thanks for the info. more food for thought. I still need to do A LOT more research and this is VERY early in the game for me.
 
Metcalf

Metcalf

Expedition Leader
That Benz engine/cj8 is sweet. I had seen that before a while ago...did he ever get the jeep finished?

A top mount inter-cooler is an interesting idea. In general top mount inter-coolers get heat soaked pretty easy. Having some kind of additional engine compartment ventilation would be a good idea. The AEV Highline fender kit I want to use comes with there hood. It has a pressure vent right behind the top tank of the radiator.
 
4Rescue

4Rescue

Expedition Leader
My best friend was going down the 4BT swap road with a pretty rough Fj40 shell, and in the end shelled out 11+K for an RHD BJ40 in fairly good shape. I can't decide which one I like more, the BJ he has, or the FJ he was going to make. Those 4BT's feel strong, and they're Cummins so they'll run forever. But then a factory Toyota Cruiser is a special thing all it's own ;)

I think your running a mechanical diesel is spot on, and will solve ALOT of the assosciated pain in the... that is can plauge swaps. All you'll need to do is get a tack/spedo, and a throtle cable hooked up and away you go.


Now get going buddy, you've got alot of people watching... ;)

Cheers

Dave
 
Metcalf

Metcalf

Expedition Leader
THE PRESSURE!!!! :)

I am still trudging away with the research and design faze of this project. The biggest hurdle for me is going to be the transmission adaption. If I elect to keep the stock jeep 6-speed ( leaning that way ) I am going to need a few large parts designed and made. Finding some CNC machine shops that can do this kind of work is going to prove challenging.

bellhousingadapter.jpg


I have to design and build a replacement for the '1' part in this diagram and most likely a custom flywheel and pilot bushing. Doesn't that look fun! Its a pretty big part. It also needs to be steel because it adds structure and effects block harmonics on this engine. A chunk of steel this size is going to take a while on any machine. I won't know for sure until I get my grubby little hands on everything if only one side of the plate needs machining. I may be able to have one side ground flat or fly cut flat and only need to do heavy machine work from one side of the plate. This would save a lot of setup time and cost.

Things I have to consider....

This bell-housing plate also holds the starter. I might be able to reuse the stock jeep starter or a high torque replacement for ease of installation. This would keep another part a factory jeep part to make replacement easier. I don't know if the jeep starter has the beans to crank over a small diesel though? Anyone?

The flywheel can also be built for the factory jeep clutch or direct replacement upgrade. I haven't known jeep clutches to be a weak link. There are a lot of stronger bolt in upgrades too. Using the stock starter ring gear would be nice too. The flywheel also has to be cut to provide the pulse signal for the crank position sensor. I am still looking into this. There was a signal/sensor thing in 05 that I am trying to find out. Does anyone have an 05-06 FSM in PDF?

The bell-housing plate also hold the crank position sensor mount.

Enough for now....more later
 
Signcutter21

Signcutter21

Adventurer
Man what a great project/ adventure. It sure looks like your doing your home work on all of it. I can't wait to start see the progression as it comes together.

Had a question, you stated that you're going to use the LJ as your platform, were you planning on using the Rubicon package (as in the pics)? Seems like a waste if your planning on putting an atlas, arbs with new D44s. A good ol X package would work too. Probably what were your planning, just didn't see mention of the platform.

Regardless, already excited for it to be done. I'm sure your right about the murphy's law too on the JK diesel. plenty of people pulling for you to do this with that in mind. lol
later,mike
 
Metcalf

Metcalf

Expedition Leader
Signcutter,

Man what a great project/ adventure. It sure looks like your doing your home work on all of it. I can't wait to start see the progression as it comes together.

It is going to be a long road thats for sure...

Had a question, you stated that you're going to use the LJ as your platform, were you planning on using the Rubicon package (as in the pics)? Seems like a waste if your planning on putting an atlas, arbs with new D44s. A good ol X package would work too. Probably what were your planning, just didn't see mention of the platform.

I'm still shopping for a donor. Starting with a Rubicon does have some advantages and I will modify my plan accordingly. With a Rubicon, if I kept the stock 6 speed, the factory 4.10 gears would work great for the planned 37" tires. The diesel doesn't need any lower gears. If I do start with a Rubicon I would just keep the stock lockers. I will have an atlas no matter what. I figure if I start with the Rubicon I can sell the transfer case to make back some of the money needed to install the Atlas. They are going for about 1k on eBay. They are a good transfer case, but I want lower gearing than that off-road, and the ability to have front wheel drive would be nice. A middle low range would also be very nice.

If I start with a non-Rubicon I will most likely upgrade the axles a little more. The cost of a 30 vs 35 spline ARB and axle set is negligible. Honestly I think the ARB stuff is stronger overall.

The entire thing is going to be a balance between cost and labor.

Regardless, already excited for it to be done. I'm sure your right about the murphy's law too on the JK diesel. plenty of people pulling for you to do this with that in mind. lol
later,mike


Thanks. I would love to have a diesel JK with the earthroamer setup...mmmm.
 
Metcalf

Metcalf

Expedition Leader
Todays research update.

I have been pouring over the jeep FSM trying to figure out how the stock jeep 4.0 PCM works and if I might be able to use it to provide gauge functions by fooling the PCM with some stock sensor inputs to make everything happy.

The short version is that the stock jeep computer can be rigged to provide some functions, but I don't know how interconnected everything is. My educated guess is the the computer is going to blow codes like crazy. I don't know if this would effect anything I want the stock PCM to do.....

Speedometer
Tachometer
Odometer/trip meter
volt meter
Fuel level
oil pressure
water temperature
Cruise control

I have a good friend going through a GM engine swap right now and he is going to try and get his PCM to do most of these functions. That will help out my research a good deal.

I have a feeling that no matter what, the stock PCM is going to blow a ton of codes, beep at you, and illuminate the check engine light. The simple solution would be to take apart the instrument cluster and remove or disable the chime speaker and the LED that activates the check engine light. That does look possible, and from all outward appearance everything would look seem less. I don't think codes actually affect the function of the gauges or the cruise control.

option two-ditch the factory gauges all together and rewire most of the jeep to accept real gauges.
 
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