I really hate it when people come along and poo-poo all over somebodies idea, especially when they're really enthusiastic about that idea. But I have to be that guy.

A 4BT will not work with ANYTHING that is currently in your ZJ. You would be closer to your end goal saying:

"I want to graft a ZJ body onto a bread truck chassis with a 4BT, and then convert it to 4WD.

There are Diesel engines out there much better suited to a ZJ, please do some more research, but know that nothing is going to be cheap, and a 4BT, being is SUCH high demand will give you the lowest gains for your dollar.

 

What would be the best diesel engine to put into a ZJ I’m planning to do the same and I’d like to go with that engine with all mods and everything I would have to buy

 

My thoughts? Good luck.

It's not that you can't stuff a 4bt into the ZJ engine bay and make it work, but you are looking at doing a LOT of mods that take both time and money. 4bt is a huge chunk of iron, and is not the best engine for a diesel swap into a unibody Jeep. There are much better diesel alternatives for the ZJ, which with some modifications will give you good power/torque/MPG in a smaller and much lighter package.

 

Free 10 grand?
http://mallcrawlin.com/forum/showthread.php?13679-Diesel-ZJ

 

Well, you won't do this with a 4bt no matter how you tune it

..this is on the extreme side though, roughly 600hp/ 1000Nm from an OM606 3.9 litre diesel :shhh:

As much as I hate Mercs, there are a few absolutely amazing diesel engines they have built during 80s and 90s, that can be built with fairly little mods to make over 200hp and plenty of torque. As long as people keep on dreaming of 4bt or 6bt swaps in here, I will be posting these diesel Merc drifting videos :laugh:

There are quite a few guys across here that have been using a bit older slightly modified Merc 5 cyl or 6 cyl diesels on XJs, MJs and ZJs, with very good results. There is also a thread on the XJ section with a guy doing IIRC OM603 swap into an XJ. These engines beat the 4.0 I6 hands down both power- and torque- wise, and are very reliable on day-to-day use. Compared to a 4bt, they make about the same torque or more, way more HP, and are much smaller and lighter. As far as I know, the older ones are easier to find there across the States.

4BT seems to be a popular engine these days there in the USA, so they are not exactly cheap. As stock, they make good low-end torque that can destroy your drivetrain and unibody/ uniframe, mostly due to the weight of the engine and the way the torque comes out. Looking at numbers only, 4BT makes about a 100hp and 245 torque - which isn't that much really.

 

So the real question is what engine will be the cheapest MD easiest to mod? I'm looking for any suggestions. I'm having a hard time coming up with a plan.

 

Here is an idea. Gets some lockers and skid plates then wheel it. There is no good reason to engine swap a ZJ other than just because.

 

To come up with a plan, you first need to define your current set of circumstances, and then define your desired circumstances. You could start with a two column list of the pro's of how your jeep is currently and the con's of how your jeep is currently. From there you can look at options to mitigate the con's and evaluate the effect it will have on the pro's.

 

Are you planning on a diesel swap just for fun, or for some benefits?

If you're just looking at better MPG, it may not be worth it - that really depends on how much you can fab yourself, and how much you need to pay for the engine & tranny + other necessary stuff.
It you're doing it as a fun project, you can do just about anything if you've got enough fabbing skills and a deep wallet. It really depends what you're looking for and what you want.

 

Www.4btswaps.com

You need to hit this site for a while.

 

Problem with the unibody is the torque. If you fab up a chassis and tie it into the unibody you will be ok. I know that there is a company that makes bell housing adapters to run a 42re trans behind the 4bt. I've seen several Dakotas with 4bt swaps. It's all about how many benjamins you want to spend. For the hassle you could stroke out your 4.0 and or get a turbo kit for it for the power and if you're worried about MPG and this thing is a highway king vs. off road monster put a lower gear in the rear end. Also switching from a mechanincal to electric fan helps out a lot. Took a Dodge Ram with the 5.9 from 13 MPG to 18 MPG just by taking the restriction out of the intake and exhaust, switching to an electric fan, and putting one size smaller gears in the rear end.

 

I'd like to see a turbo OM603 in a ZJ, that would be interesting.

I like it where it is in my 300D better though. And when I kill the 300D my buddy wants the engine for his mog.

The 4bt and NV4500 swaps I've seen are amazing, but theres no floorboards left. It doesn't make sense economically.

 

I'm not a huge fan of the 4BT. It's big, it's heavy, it's noisy, it's shakey, it doesn't make a lot of torque, it's not very efficent, and it's overpriced. The similarly-named, identically-displaced Isuzu 4BD1-T is at least a tad cheaper, though it only mates to Isuzu and GM transmissions. Some might consider that a good thing since 4L80E parts are easier and cheaper to come by than various A518 bits.

Honestly though, you don't get much benefit from swapping a diesel into a ZJ. The engines that came in the Jeep will do a lot more for the same money than a diesel will, with less ingenuity required. And if you have to ask what's needed, you probably don't have the ingenuity to swap a diesel in yourself.

If I was dead-set on a diesel engine, I'd look to VW TDI. I know somebody made a kit to swap in a TDI to a TJ- I think it may have been the 2.0TDI. That'd be lighter, more economical, more comfortable, and probably a bit easier to squeeze some extra from. The fact is, in the diesels-for-passenger-cars market, Europe is WAY ahead of America, whose diesel market shrunk to just-big-trucks after GM made a cock-up of it in the 70s.

 

I plan on doing a 4Bt conversion or swap for many reasons. First off, If I did not have one laying around it would not be worth it to me, but I do so it has to go some where! The 4BT weighs around 800 lbs. A Dodge 360 weighs about 620. That is about a 180 lb increase. Not as much as you would think. Mileage is a factor. How cool would it be to have a 4x4 with 33's that got 30 mpg and could idle up most rock climbs. Most diesel motors only have three wires to operate. Electronics are not the Issue.
As several people here have said earlier, the main problem is modifying the uni body to carry the torque of this motor.
And yes this motor does sound like a six year old dumped his rock collection into his moms cloths dryer !
Do not get in a hurry to do a diesel conversion. If you decided to do it study everything you can about conversions. Once you know what you need, start scavenging parts. I am enjoying my ZJ now with a 318. It runs fine, but when it gives out I will put a 4bt in.
Also go to you tube and watch some of the videos of land cruisers, broncos etc that have 4BT's in them. They have strong frames to care the torque, a ZJ does not and has to have more support installed in the uni body.
There are many shops that install Isuzu, Cummins and others into 4x4's. If you send it off to have it done it will cost you over $20,000. I stick to the "Built not bought" rule of thumb.

 

Good luck fitting it. The 318 is shoe horned in as it is. You'll be doing lots of cutting in the bay to fit it. Not to mention clearing the suspension. You may as well go all out and put a 6bt in. It's better balanced and won't shake the ZJ apart.

 

Of what I've seen of the 4bt and 6bt swaps into ZJs or XJs, usually quite a bit of suspension lift needs to take place along with possiboy long arms for clearance. As I wrote on the previous page, anything can be done, but the Cummins bt- engine isn't exactly the best alternative for a unibody Jeep..

 

On the one I have heard of, I recall the guy generally hated it.

 

I seem to remember that same feeling - it was a green one if I recall. Guy spent a bajillion hours on it, it needed 7" of lift just to clear stuff and was bumpstopped to hell just to keep the axle clear of the tall-*** motor. He eventually gave up and sold it for way less than he'd put into it.

 

It's been done. Lots of fab and lots of electrical work. The 360 is lighter, more powerful, and just as economical if you factor in the price of diesel. But if its what your heart (and wallet) desires, go for it. You'll lose a good but of ground clearance, so be ready for that.

Sent from my iPhone 9 using JeepForum

 

The only one I've seen had cut out the trans tunnel and most of the pass floor boards almost to the backseat to get clearance.

What trans are you going to run?

 

I still say, if you're dead set on burning oil, you grab a VW TDI kit and go that route. It's easier, it won't throw off the balance of the Jeep, and most of the engineering has already been done. It's a bit expensive, but all the fab work and ruining your Jeep you'd have to do to cram a B-series into a ZJ has its costs as well.

However, make no mistake: no way are you going to get 30mpg from a ZJ, and it won't give you any more super-crawl than you're already capable of. In fact, the gas V8s in the ZJ have more torque than a stock 4BT, and it peaks at 3200rpm, which is like 2mph in 4Lo in 1st gear.

 

I still say, if you're dead set on burning oil, you grab a VW TDI kit and go that route. It's easier, it won't throw off the balance of the Jeep, and most of the engineering has already been done. It's a bit expensive, but all the fab work and ruining your Jeep you'd have to do to cram a B-series into a ZJ has its costs as well.

That, or any of the Merc diesels. VW diesels are 1.9 or 2.0 ones, Merc has a bit larger displacement with similar reliability, more power/tq, and close to same MPG.

VW TDIs are great for sure, just on the small side for a ZJ. Here across the pond ZJs and XJs use a 2.5 litre VM Motori turbo diesel - which was and still is a really crappy engine with poor reliability

However, make no mistake: no way are you going to get 30mpg from a ZJ, and it won't give you any more super-crawl than you're already capable of. In fact, the gas V8s in the ZJ have more torque than a stock 4BT, and it peaks at 3200rpm, which is like 2mph in 4Lo in 1st gear.

This exactly. 318/360 also has about 80% of it's torque available at relatively low RPMs - and it's there the very moment you press on the skinny pedal. I've seen too many Toyota LCs with souped-up diesel engines fail at giving the oomph instantly when needed.

 

If you want low crawl the $1500 for a NP241OR and then new driveshafts is gonna be better than any diesel conversion.

Agreed that if you're trying for diesel the TDI or Mercedes Benz route would be a better route. The AX15 adapters for the tdi engines weren't a bad option.

As for electronics, it's not so much that you need the electrics to run the engine as you need the electrics for the rest of the jeep to not freak out. When badbird did his LS swap he ended up with a completely custom dashboard.

 

I'm really glad that this thread has caught traction again. I remember 7 or 8 years ago when diesel swaps really flared up. Every single person I know that did a diesel swap has sold their project and moved on.

I come from the SJ community, which is full size and full body-on-frame, but this goes beyond just Jeeps. Everyone I know that swapped a Lehman, or Cummins, and even a Kubota (into a sidekick) praised it during conception and then dumped it as soon as they could.

Diesel has it's place but most of what people know about them is smoke and mirrors combined with a lot of pipe dreaming.

No diesel engine will save you a single penny. Every extra MPG will cost you more at the pump, at the service interval, and especially in hard parts like turbos and exhaust manifolds.

Diesels are NOT better for the environment. the 20% better volumetric efficiency (theoretical best) is more than offset by the additional sulfides, NOx, and HCs diesels dump out the pipe.

More over is the "torque" myth. If you need more rotational force, the answer is gearing, not an engine swap. Look at every top level internal combustion engine motorsport there is. Diesels only compete against other diesels (tractor pulls, drag racing[ all the videos I see of "chipped" diesel trucks stomping a car, the car has a small displacement gasoline engine]) because high RPM engines running on Gasoline, Ethanol or NitroMethane win the day. Funnycars, Formula one, Sprint, Super Speedway, Monster Trucks, Top Fuel, Isle of Man, Dakar, Baja, etc etc etc.

There is a threshold where diesel becomes a viable option. Semi trucks benefit from running diesel, ships benefit from running diesel. Diesel has it's place, but I have seen NO proof from anything anywhere showing a recreational passenger vehicle being better off running diesel, regardless of purpose.

 

To be fair, Mazda was competitive in LeMans with their diesel LMP2 car because it didn't have to stop for fuel as often as some other cars on the field. And diesels do have their place in passenger cars. European diesels are far more efficient than US diesels, because they're not stymied by as much emissions equipment.

Diesel also does typically produce more specific torque- torque per unit displacement- than contemporary gas engines. High compression and long strokes do help in that regard.

But a diesel swap isn't going to save any money, and unlike the TJ and XJ, we never got the 2.5l gas engine in our Jeeps. Instead we got bigger engines than any other period Jeep got, and those make more torque than diesels that fit, so they're far more sensible options.

 

To be fair, Mazda was competitive in LeMans with their diesel LMP2 car...

I think you and I are on the same page, because my counter point would also be Mazda, with there Wankel rotary engines that produce negligible torque at low RPMs yet spank supercars with their outragous redlines.:thumbsup:

To the OP and those following along, remember that torque and HP are both calculated numbers. Butt-dyno catches a lot of flak, but what else really matters? Google 5252RPM.

P.S.

Instead we got bigger engines than any other period Jeep got.

Except for (4-0) one.:laugh:

 

Didn't audi run TDI at LeMans and do quite well too?

Technically the ZG did get the 2.5l crapheap.

If you want a diesel grand get the new WK2, which does get real world over 30mpg. It's also lighter, more aerodynamic and the air suspension lowers on the highway for fuel efficiency. The 27 speed trans helps too.

 

The 4bt is a great engine and is considered medium duty unlike every other diesel on the consumer market. It has the potential for make 400 to 600 reliable HP and still get 30 mpg or more. But putting one in a ZJ would have to be a labor of love. The easiest way would be to get a 3/4 ton Dodge frame and section it, then drop the ZJ on the frame.

 

I have a 4bt that is going in my 1941 Dodge military. That is a more appropriate use for this class of engine. I would like to stick a D300 Mercedes engine in my ZJ, if I could ever tame death wobble. As it is I am about ready to drive my '95 to the bone yard and toss them the keys!

 

Full disclosure: I have a 1993 Dodge W250 with 410,000 miles on the original engine, make 40psi with hybrid turbo and marine injectors, can oil down the asphalt in the first three gears and run 14s with limited traction, and still get better milage than my ZJ 4.0l that is a wheezing pig. But we have three GC's because they will go anywhere.