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Im thinking Diesel!

4K views 20 replies 11 participants last post by  Lucas53 
#1 ·
For a long time I've been enthralled with the idea of having a diesel put in a jeep. I've read cummins 4bt conversion post after post and I finally have the funds to be comfortable to do this.
Before I pull the trigger, I want two things out of this post.

1: what are your thoughts on the 4bt diesel swap?

2: (more importantly) from what you all have read or hopefully personally experienced, what are the minimum requirements on parts for a jeep undergoing the swap? For example, I've read it needs at least a 4" lift because of height difference between the motors. One thing specifically I'm worried about is whether I need to beef up anything to counter act the weight for the new engine?

I'm only mechanically inclined enough to do basic maintenance and repairs. A local shop is doing the swap for me. Just want to have her ready to go.
 
#5 ·
I'll definitely keep you updated and that's what mainly what I was thinking. The 4bt is apx 750lbs which is apx 250-300lbs heavier than the 4.0L I6 weighing in at 500.

I personally think the 4bt is a heavy pig of an engine. If I were to go diesel it would be a TDI engine. Lighter than the 2.5 but with minimal tuning it'll make more torque than the 4.0, albeit doesn't quite have the horsepower.

Some spec comparison:

4BT stock (these numbers vary greatly from mild to wild):
105hp @ 2300 RPM
265 ft-lb @ 1600 RPM
Wet weight ~750 lb

1.9L TDI (specs from HPA Motor sports for sofware tuned engine)
170hp @ unknown
265 ft-lb @ unknown
Weight, 50 lb lighter than Jeep 4 cylinder (~290lb)

Jeep 4.0
190hp @ 4600 RPM
225/235 ft-lb @ 3000/3200 RPM
Weight ~500lb

Those TDI's are great engines, however, in my opinion, they do not be long in a jeep/truck! Just something about a cummins that keeps drawing me to em'! Thanks for posting the specs. I was just re-reading them on another site as I read your post.

You make a great point for other people trying to choose an engine for a swap though. From my readings... The TDI, install wise, is a lot easier... less tweaks easier to plug and go!
 
#4 ·
I personally think the 4bt is a heavy pig of an engine. If I were to go diesel it would be a TDI engine. Lighter than the 2.5 but with minimal tuning it'll make more torque than the 4.0, albeit doesn't quite have the horsepower.

Some spec comparison:

4BT stock (these numbers vary greatly from mild to wild):
105hp @ 2300 RPM
265 ft-lb @ 1600 RPM
Wet weight ~750 lb

1.9L TDI (specs from HPA Motor sports for sofware tuned engine)
170hp @ unknown
265 ft-lb @ unknown
Weight, 50 lb lighter than Jeep 4 cylinder (~290lb)

Jeep 4.0
190hp @ 4600 RPM
225/235 ft-lb @ 3000/3200 RPM
Weight ~500lb
 
#7 ·
I'd like the idea. I think the perfect engine would be the VM 3.0L engine they're using in the Ram and GC. That's if you could get your hands on that engine. Hopefully next year it finds its way into the Wrangler. One thing for sure I think the conversion would be a lot easier than using the 4bt engine.
 
#8 ·
Stay away from the Cummins with the Bosch injection,

The VP44's in the 1998 thru 2002 are junk. The have internal computers that I am told fail due to lead free solder.

My 2001 Dodge w/Cummins has 225,000 and I have replaced 3 injection pumps. You're lucky if one goes 100,000 miles
 
#9 ·
Stay away from the Cummins with the Bosch injection, The VP44's in the 1998 thru 2002 are junk. The have internal computers that I am told fail due to lead free solder. My 2001 Dodge w/Cummins has 225,000 and I have replaced 3 injection pumps. You're lucky if one goes 100,000 miles
That's crazy, thanks for the heads up. I'll keep that in mind when I'm buying the engine.
 
#10 ·
I am putting a VW AHU TDI into my 2002 TJ. If you get the correct turbo and tune 200+hp is easy, much more than 150hp on the stock turbo is asking for trouble. I have seen dyno slips for a TDI with 382HP at 5,200 rpm...I don't think it would last 100,000 miles but the power is there. I am making my own adapter as HPA wants about 4x what it is worth. I am a VW nut so it only makes sense to me. I am actually going to go with a Manual VE pump from a 4b with a 12mm pump head. I should be 220hp to the wheels. If you are going for big boost go with a Holset or Mitsubishi turbo as they are built 10x better than KKK or Garrett turbos.
 
#14 ·
I have driven several VW's with well into 300,000+ miles with the bosch VE pumps. My daily now has 280,000. If you change the filter when they say to and run a great fuel lubricant like Scheaffers or stanadyne and don't run junk diesels in them, they last almost forever. There are a couple models that have a really high camplate that will take out the springs in the pump head, but if you build a pump from an ALH vw with the 11mm head *automatic trans cars* the camplate in them is perfect.
 
#15 ·
Lots of work and expense with a net decrease in value as no one knows what parts it needs and how well it was done.

As a play project to sink in excessive time and money and keep forever fine otherwise if you want a diesel like a hummer buy one

Expect as a father and son/daughter project for learning and bonding it is a rat hole for money
 
#17 ·
Not really. I have less than 2,000 in the jeep. I own several vw engines for my other vw cars. With some insight and 1/2 of a brain that I have I am building all the pieces myself. Unlike the HPA kit that you have to buy a 200.00 Passat starter or other kits for other vehicles that you have to send in the flywheel to be machined, I am building it so everything behind the adapter is Jeep. You could go into any parts store and buy a clutch, flywheel, and starter for a 4.0 if you needed. I will be using the stock fuel tank just deleting the fuel pump. Basically, to remove mine and sell it with a 4.0 should be as simple as dropping the fuel tank, adding the pump, unbolting the vw engine and adapters, and putting the 4.0 in. For what I see these jeeps going for and what I have in mine it wouldn't be too hard to sell it for fair market value. People just have to want what you have in the jeep to start.

I would agree if you are ignorant to VW diesels then the timing job alone could cost you more than what I have in the jeep. Especially if you fail and ruin the cylinder head and block by bending everything internally by being more than 1 tooth off.

The TDI diesels are at least 15% more efficient of an engine than the older IDI 1.6s. I love the 1.6 especially at high rpms as I have one that is not dyno run yet that is expected to be 200whp. But the TDI will be much more suited to the TJ than the 1.6. Being that they are more efficient it will get better mileage and make better use of the turbo. So the same turbo on my 1.6 might be able to get 50 more whp in my vw.
 
#19 ·
I DD a 4BT Scrambler. The engine is awesome for what it is = mechanical injection diesel technology. It is heavy & loud But easy to work on & easy to get parts for. It all depends on what your needs are - I can knock down 30mpg all day & with a 33gal tank I don't have to fill up too often. It is not a speed demon off the line, but I can run with traffic on the interstate (get Lots of great looks when I blow past people). Would I want this engine for off-road use? No. A lighter modern diesel would perform better there, be it mud or rocks or sand, whatever.
Budget would be the biggest issue, my swap was VERY economical because I did all the work myself & got a good deal on the engine. The newer diesels are Much more complicated, with lots of electronics, Etc. That being said, I would Love to have one of the new 3.0L diesels, Gale Banks Engineering is supposed to be working on a swap kit, if they can simplify all the periphrials the will have a winner.
If you have any questions from an actual diesel Jeep owner, fire away.
 
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