Tartarus

Sorry about the length of the post --

I just inherited a 2000 Jeep Wrangler in excellent condition. Only issue is, the drivetrain is missing. I can have a bit of fun with it, and rather than shop around for an inline six gasser/AX-15 tranny, etc., or mod for a Chevy crate or something, I'd like to do something interesting. Fabricating is not a problem, as I have access to both the facilities and the "talent".

I have an NV4500 transmission and a paired NV241D transfer case I picked up in a yard cheaply. I'm wondering about using an ISB engine with this combination in the Wrangler. No -- not the 5.9L six cylinder -- the 3.9L ISB 170 four cylinder. I can get a good deal on one through a Cummins distributor in Virginia, and have it transshipped.

I'm aware of some of the issues -- driveshaft lengths and positioning, the need to replace the Dana 35c and 30 axles with 44's or 60's, fabbing mounts and cutting holes, intercooler mounting, an extra crossmember, designing a heavier suspension, etc. I've been told by Cummins people that the ISB 170 is a direct bolt-up to the NV4500, though. Not sure about that. Anyone had any experience with this engine? How does it drive? Too much vibration? Turbo options? Any big problems with it?

kandgo

I do not remember for sure,but I think it was in the {other} forum, in the last few days there was a photo of someones jeep with the 4 cyl 3bt in it, Goodluck, Rick

Wilson

I think the 3.9 is a cool unique idea. I dont have any personal experience with one. I do know of a jeep cj that has a 6.2 detroit out of chevy in it though.

Holsteinman

I have seen a 3.9 in a Jeep before, but do not know what it takes to put one in.

MCummings

http://www.gltdr.org/thunder2002/gal...00404.jpg.html

http://www.gltdr.org/thunder2002/gal...01070.jpg.html

This Jeep had lots of work done to it. Including Air Suspension, front and rear. Last I heard it was pumping 300HP ?
4BT in it as I understand.


Merrick

Haulin_in_Dixie

The back of the 4 is the same as the 6 so what fits one should fit the other. I believe the front is also. Found some other info that may help the conversion. I have been looking at fan hub mounts, there are a bunch of them, some use the same bolts as the Dodge and some use the four bolt holes above them. That should give some latitude on placing the fan unless you use electric, then you don't even need the hub. I have been looking for one three inches lower, think I found it, have to go and measure on a block. I want to raise the body three inches and retain the fan/shroud as stock.

Scrambler250

The biggest disadvantage of the ISB in a jeep is the weight. I plan to eventually put a diesel in my scrambler, and from what I've found the chevy 6.5 turbo is the easiest swap. There is a guy on off-road.com (dieselyj I believe) who has done this swap and has alot of info on it, and I think he chose the 6.5 over the 3.9. The 6.5 mounts the same as a chevy 350 (no problem finding mounting kits for a jeep), is much lighter than a cummins (supposed to only be 150 lbs. more than a 350 gas), and bolts right up to the NV4500. I think with the 6.5 you can get by with minimal suspension mods, but you'd still need to swap axles. The biggest problem is the height of the 6.5, but there are cowl induction hoods out for jeeps now that may solve that prob. I would definately try to e-mail the guy at ORC and get some feedback from him.

Now before I get cussed off this board for mentioning the 6.5 over the cummins, I'm presenting this from an ease of swap stand point...

Wilson

Check it out, here is one on ebay

http://cgi.ebay.com/ebaymotors/ws/eB...tem=2455122735

Haulin_in_Dixie

quote: The 6.5 mounts the same as a chevy 350 (no problem finding mounting kits for a jeep), is much lighter than a cummins (supposed to only be 150 lbs. more than a 350 gas), and bolts right up to the NV4500.

And all this time I thought that was what welders were made for. Someone who cannot weld up mounts has no business taking on a project like this one. I also doubt that a 6.5 is lighter than the 3.9. A big block v8 gasser is 700 pounds. The 5.9 weighs in at 960 pounds, the 3.9 has to be considerably lighter than the 5.9. I bet its about the same as a 6.5 if not lighter. With all the mount holes on the sides of these blocks, they would be a snap to build mounts for. Mounts that would bolt up to the 350 pads if that is what you want. And if you want to save weight, mount a beefed 727 on it with a 205 transfer. And you don't have the width problems with the steering and exhaust.

Scrambler250

quote: I'm presenting this from an ease of swap stand point...

Although, there really are some easier swaps out there. The CJ5 had a diesel option (perkins I think), but I think that was a 90 hp or less engine. The euro version of the cherokee was available with diesel, and a few of those engines have made it into the US. It's been a couple of years since I looked into doing the diesel swap but at the time there were a lot of options. I've heard of a few jeeps with the VW TDI, a diesel from a scout or scout II has been used (low performance, seems like though), and I'm sure plenty of others.


Haulin_in_dixie: You're right about welding skills, and anyone thinking about any swap should be ready to do some fabrication too. From what I remember, the 6.5 didn't have any clearance/interference issues with the jeep steering or exhaust. Most (if not all) the 6.5's had the NV4500 behind them, and it's not too bad to mount a D300 from a CJ, or an atlas if you've got deep pockets, to that tranny. I had always heard the 5.9 was much heavier than what you quoted. Do you know what (if any) applications had a turbo on the 3.9? Do you know the hp/ft.lbs. rating of the 3.9?

Haulin_in_Dixie

The 960 pounds is the Cummins listed weight of the 24 valve, I doubt that the 12 would be heavier. It should be close anyway. I may be able to see one with the turbo. I think one that is near here has one. I have seen several 3.9 engines at Cummins, I will check for sure, but yeah they do have a turbo model. Taking experience with the Detroits, the 3.9 would be 4/6 or 2/3 of the power of a 6 cylinder in what ever dress you put it in. Same engine, two less cylinders. That is exactly how the Detroits are rated for the different engines. ie 6-71 238 horse, 8v71 318 horse. Can't see how the Cummins would be different, same cylinders and stroke, each cylinder makes a specific amount of power.

induchman

The ISB 145/170 3.9L engine weighs 773#

Tartarus

Well, I started this thread, so I guess I'll weigh in.

After hauling the TJ down to a friend's shop and doing measurements, I decided to go with the Cummins 3.9L ISB. The deal I got on it was too good to pass up, and the whole point was to put a commercial-grade turbo-charged diesel in the vehicle and use it as a wicked off-road climber -- qualifications that the Chevy 6.5 doesn't satisfy in terms of durability or torque/rpm profiles, IMO. Plus, we're playing around with it, so we don't have to be too cheap and easy.

The engine arrived at the freight dock this morning, but I doubt if we're going to have time to begin the project until April.

BTW, the 3.9L develops 170 hp and 420 lbs. torque at 1600 rpm. Motorfreight company weighed it at 714 lbs. It is turbo-charger ready; I'll probably go with an HX35 from Piers, or equivalent. The weight is within the capability of a TJ Wrangler with aftermarket suspension redesign, although it'll be front-heavy.

I remember someone here or on TDR once saying that inline diesel four cylinders put out a lot of vibration -- so we're doing some thinking about motor mounts and ways of dampening.

Now for the really important question -- any suggestions on what color to paint the Jeep?

Haulin_in_Dixie

You might consider the mount system that the Ram uses. A bit of a pain but sure does damp the engine. You probably could use the cast mounts from a ram and just have to build the twin plate mounts on the chassis.

wannadiesel

I think an HY35 would be perfect for this. Remember that you've only got 2/3 the exhaust volume to spin the turbo, so even an HX35/12 won't have the immediate spool up that you want for this sort of application. Slightly used HY35's usually go for less than $300 on Ebay.