I have been researching the new 4 BT conversion for my JK

[Jim K in PA]

Paying 40% more at the pump to go 30% farther while paying $5,000 - $15,000 for the privelege of doing so really doesn't make a lot of sense.

You are better off focusing on building efficiency in the vehicle you have, saying the hell with it and building for power because it's fun or switching platforms entirely.

2¢

Bingo. I could put an old tech Mercedes OM617 3.0L turbo diesel in my LJ Rubicon with a kit for under $2k. It would have 40% less power, and get me maybe 25mpg. Totally not worth it. The 4BT can be tuned to put out gobs of power, but then the fuel consumption is as bad as my stock 4.0 gas engine.

I am in the throws of comparing a GM 4.8L Gen IV engine swap to an aluminum headed stroked version of my 4.0. Even though the aluminum headed stroker is going to cost more than the V8 swap, all the ancillary issues that go with a non-native repower more than make up for the cost difference. IMO, I like to drive my Jeep, not tinker with it ad nauseum. Hesco makes a stroker kit for the JK 3.8 now, but I am not sure what the gain vs cost ratio is.

 

[Dan Grec]

The VM 2.8 is not great.

I've heard this a few times recently, but always 2nd or 3rd hand.
I'm not proclaiming it to be the best engine ever produced, but I've never heard any real complaints from actual owners.

What do you not like about the engine?

The fact that it already exists in a Wrangler makes it extremely appealing in my eyes.

-Dan

 

[Dan Grec]

Bingo. I could put an old tech Mercedes OM617 3.0L turbo diesel in my LJ Rubicon with a kit for under $2k. It would have 40% less power

How much torque?

(I don't want to get into the endless power vs. torque debate, because we all know power is just torque at a given rpm...)
The Jeep will be massively snappier to drive with 120 horses and 350 ft. lbs. than stock.

-Dan

 

[Ryanc]

I honestly dont think it is worth it. I think I would look at transfer cases, transmission, and axle gearing before I messed around with that. With my 6 speed, 4:1 transfer case, and 5:13 gearing I can go anywhere. I can essentially put it in first, get out of the jeep, and watch it crawl up a mountain.

 

[reece146]

Bingo. I could put an old tech Mercedes OM617 3.0L turbo diesel in my LJ Rubicon with a kit for under $2k. It would have 40% less power, and get me maybe 25mpg. Totally not worth it. The 4BT can be tuned to put out gobs of power, but then the fuel consumption is as bad as my stock 4.0 gas engine.

I am in the throws of comparing a GM 4.8L Gen IV engine swap to an aluminum headed stroked version of my 4.0. Even though the aluminum headed stroker is going to cost more than the V8 swap, all the ancillary issues that go with a non-native repower more than make up for the cost difference. IMO, I like to drive my Jeep, not tinker with it ad nauseum. Hesco makes a stroker kit for the JK 3.8 now, but I am not sure what the gain vs cost ratio is.

I keep reading that the OM617 can be tuned to 200hp/300tq but then that costs money and you have to know what you are doing to do that.

Why bother with the Al head? To run a touch more compression? I'd rather keep robustness under pear shaped overheat conditions. An insurance policy of sorts.

I keep entertaining a GM swap or a Om617 swap for my MJ but I always come back to the I6 just because it isn't a PITA. Anyone that costs out an engine swap based on just a kit price and the price of the new drivetrain is kidding themselves in order to justify a swap. Got your numbers? Multiply by two and you might be in the ball park and that is saying nothing of the time involved.

If it's a labour of love versus just optimizing a driver you may or may not be able to justify a swap. IMO swapping an engine into a vehicle that is to be used as a tool as opposed to a plaything doesn't make sense. If you are unhappy with the vehicle enough to be entertaining extreme measures like an engine swap I feel it's time to trade over to something else.

I'm doing similar mental gymnastics with my race car: swap, blower or sell. I feel the OP's pain. In my case the blower or stay put and sell are the only things that really make sense, if spending $6k on a turn key blower kit can be said to make sense in a strange way. Being turn key and being able to keep the existing equipment already added to the car are the only reasons I can entertain this idea semi-rationally. A ten year old car in any market is worth nothing regardless of what is bolted to it si I'll lose lots of money if I sell the car.


2¢

 

[DesertJK]

I just typed a big long response and lost it. Crap, I can't type all that again. I'm going skiing, see ya.

 

[Jim K in PA]

How much torque?

(I don't want to get into the endless power vs. torque debate, because we all know power is just torque at a given rpm...)
The Jeep will be massively snappier to drive with 120 horses and 350 ft. lbs. than stock.

-Dan

Dan - How I wish that were the case with the old MB engine. The stock engine is rated at 125hp and 180 lb-ft. It also weighs 628lbs. My stock 4.0 is 190hp/235tq and weighs 515lbs.

The OM617 can be uprated with a modified pump, increased boost, and an intercooler. "Safe" power levels supposedly in the 200hp/300tq are doable, but then the mileage drops. A stock engine might get upper 20s i na YJ/TJ, but tweaked it will be back down into the lower 20s at best.

Some info:
http://en.wikipedia.org/wiki/Mercedes-Benz_OM617_engine

The kit source: http://mercedesdiesel4x4.com/default.aspx

 

[Jim K in PA]

I keep reading that the OM617 can be tuned to 200hp/300tq but then that costs money and you have to know what you are doing to do that.

Agreed. See my prior post.

Why bother with the Al head? To run a touch more compression? I'd rather keep robustness under pear shaped overheat conditions. An insurance policy of sorts.

Actually both. The AL head allows for more compression and less need for the ECU to retard timing due to knock, both of which results in better efficiency (more power/less fuel) As to the robustness issue, in overheat conditions the long I-6 cylinder head is known to warp almost as easily as an AL head. It is not an insurance policy, IMO. I have driven and raced many different configurations of engines with dissimilar metal components (including rotary engines) and to damage one catastrophically takes some effort or really bad luck. BTW - the Hesco ACH has a 5/8" thick deck, almost twice that of the stock cast iron head. Pretty robust design.

I keep entertaining a GM swap or a Om617 swap for my MJ but I always come back to the I6 just because it isn't a PITA. Anyone that costs out an engine swap based on just a kit price and the price of the new drivetrain is kidding themselves in order to justify a swap. Got your numbers? Multiply by two and you might be in the ball park and that is saying nothing of the time involved.

Agreed 110%. I like my 4.0 very much. It's power is adequate for a stock truck weighing 3800#. Load it, add an RTT, get a good head wind, and start climing a decent hill, and the word "adequate" no longer applies! I have a good handle on the costs for the V8 swap into my Jeep, but it still comes in at $5-6k. The biggest PITA with that swap is the electrical, unless you are OK with a constant CEL, no odometer, partially functioning guage cluster, etc. The stroker (even a cheaper, lower compression version) will give me the additional power to handle the additional loads of longer trips. I like everything else about the truck (except the fuel consumption).

IMO swapping an engine into a vehicle that is to be used as a tool as opposed to a plaything doesn't make sense. If you are unhappy with the vehicle enough to be entertaining extreme measures like an engine swap I feel it's time to trade over to something else.

Agreed again. In fact, I looked into the more current offerings in a variety of configurations, and came away with nothing that was better "enough" to justify the significant cost to change vehicles.

 

[reece146]

The biggest PITA with that swap is the electrical, unless you are OK with a constant CEL, no odometer, partially functioning guage cluster, etc.

IMO, any swap that doesn't adress the elctrical is incomplete. I woldn't be able to tolerate it.

 

[Jim K in PA]

IMO, any swap that doesn't adress the elctrical is incomplete. I woldn't be able to tolerate it.

Me either. All those issues are solvable in one way or another, but will take time and $$. I am also not anxious to go to a DBW throttle. The mechanical TB on my Jeep is just fine . . . and simple.

 

[Dan Grec]

Dan - How I wish that were the case with the old MB engine. The stock engine is rated at 125hp and 180 lb-ft. It also weighs 628lbs. My stock 4.0 is 190hp/235tq and weighs 515lbs.

Thanks for the info. Wow. That thing is more of a lump of ******t than I thought.

Only 180 ft. lbs. out of a diesel? pfft.

Add that to the list of reasons I think the 4BT is a hunk of ******t

The VM/Motori 3.0 is rated at 237 horses and 405 ft. lbs. , as sold in the GC in the UK right now (jeep.co.uk)

-Dan

 

[Jim K in PA]

Thanks for the info. Wow. That thing is more of a lump of ******t than I thought.

Only 180 ft. lbs. out of a diesel? pfft.

Add that to the list of reasons I think the 4BT is a hunk of ******t

The VM/Motori 3.0 is rated at 237 horses and 405 ft. lbs. , as sold in the GC in the UK right now (jeep.co.uk)

-Dan

Sad but true on both engines. The 1.9TDI swap is an interesting exercise, but there is not enough power even after tweaking to make it worth considering for a heavy rig (IMO).

The VM motor is not an easy swap into anything that didn't have it already. Modern common rail diesels with electric injection pumps are not the simple mechanically controlled machines that the MB and Cummins engines are. It is even more complex than a GenIV V8 swap due to the emmissions controls.

From a bigger picture perspective, I also think that the pricing scheme (tax structure) of diesel fuels in the US is not conducive to converting any vehicle over. The fuel price differential eats up most if not all the efficiency differential, making the cost of conversion just about unrecoverable. If someone really wants a diesel (I personally don't), then buying one that started life that way is a much wiser path. To me, the only reason for a diesel conversion would be to increase the driving range of the vehicle. But, there are far cheaper ways of doing that with a gasoline powered car as well.

Sorry Dan. I know you are a big advocate, but I don't see the rationale to support it.

 

[Dan Grec]

The 1.9TDI swap is an interesting exercise, but there is not enough power even after tweaking to make it worth considering for a heavy rig (IMO).

I agree. Could be interesting in the YJ/TJ/ 2 door JK.
I'm not expecting a speed monster, but something drivable that achieves towards 30MPG.

The VM motor is not an easy swap into anything that didn't have it already.

Very true. That's why I'd be looking at the 2.8 VM, and I'll be watching the 3.0 very, very closely when it comes out in the GC.
I think it's impossible a few shops won't at least attempt the conversion, so it will be great to see how "doable" it is.
(come on AEV!)

From a bigger picture perspective, I also think that the pricing scheme (tax structure) of diesel fuels in the US is not conducive to converting any vehicle over. The fuel price differential eats up most if not all the efficiency differential, making the cost of conversion just about unrecoverable. If someone really wants a diesel (I personally don't), then buying one that started life that way is a much wiser path. To me, the only reason for a diesel conversion would be to increase the driving range of the vehicle. But, there are far cheaper ways of doing that with a gasoline powered car as well.

True again, for the US.
I'm in Canada, where diesel is only fractionally more expensive than gas.
I also plan on driving my future expo vehicle 100,000 miles, mostly in countries that have cheap plentiful diesel.

I'm not the average North American customer, and I realize to get what I want, I may very well have to go overseas to get it. I will if I have to.

-Dan

 

[Jim K in PA]

True again, for the US.
I'm in Canada, where diesel is only fractionally more expensive than gas.
I also plan on driving my future expo vehicle 100,000 miles, mostly in countries that have cheap plentiful diesel.

I'm not the average North American customer, and I realize to get what I want, I may very well have to go overseas to get it. I will if I have to.

-Dan

Dude - you're in Canada! You have options we don't down here as far as importing JDM spec diesel Patrols and LCs. DOOOOOOOOO IT!

So when are we leaving and where are we going? Or would it be easier to say where you're NOT going on a 100k mile trip?

 

[Dan Grec]

Dude - you're in Canada! You have options we don't down here as far as importing JDM spec diesel Patrols and LCs. DOOOOOOOOO IT!

So when are we leaving and where are we going? Or would it be easier to say where you're NOT going on a 100k mile trip?

Haha, Yeah, I live in Whitehorse, in the Yukon these days. Loving life up here in the North. It's -40 today (C and F are the same at that temp)

I see quite a few JDM Patrols and LCs getting around, I spot them a mile-out with the steering wheel on the wrong side.
There has been a Diesel LC for sale up here for months.. only something like 150,000kms for $4500 (I don't have more info)
While they interest me, they still only get around 18-20mpg, which I very much want to do better than.

My next serious expedition is quite a few years out.

-Dan