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2005 LJR R2.8 build

DieselJeep

TJ Enthusiast
Joined
Oct 31, 2018
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KY
I went through a field last weekend that was above my hood and all I could think about was plugging up my intercooler and radiator. Luckily it wasn't too bad.
 
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1945GPW

1945GPW

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Mar 12, 2018
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Figured I’d do an update, put a little over 1000 miles on the jeep. We are having an over heating issue going up hills and pretty much anytime a significant load is on the engine going over 40mph. Axis is working with us to get it resolved. Current plan is to replace the fan with a GM fan that pulls i believe 4600 CFM, about 800 more than the current setup. I’m doubtful this is going to fix the problem as it’s only at hwy speeds it overheats. If that doesn’t work I think we are going to try an egr delete. I’ve seen noticeably cooler temps in trucks with this so I’m hoping it will work for the jeep as well.

On a good note our first two tanks averaged 25 mpg hand calculated and adjusting for the odometer from the larger tires. This is a mixture of on and off road driving. After we got the flash from Cummins for added torque, our latest fill up averaged 27.5 mpg mixed driving.

So far I’m impressed with the power and mpg of the Cummins. Current downside is the overheating and a rattle coming from the transmission while in neutral, could just be the vibrations from the engine transmitting to the input shaft magnifying the rattle but I’m not sure yet.

CC2356E8-FF4A-4AFF-AC3C-CF8AA66144C6.jpeg
 

Chris

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How loud is that Cummins compared to your typical diesel truck? One of the turn offs for me with diesel has always been how obnoxiously loud they are. Maybe they've gotten better though?
 
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1945GPW

1945GPW

TJ Enthusiast
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How loud is that Cummins compared to your typical diesel truck? One of the turn offs for me with diesel has always been how obnoxiously loud they are. Maybe they've gotten better though?
I had to Edit my original post because it all depends what year and type diesel truck your referring to. The older ones are noisy in reference to engine clatter compared to the newer ones. I’d say the r2.8 is a mix between 3rd gen cummins truck and a 2004 VW tdi if you’ve heard one of those run. It’s not quite as loud as the truck and has more of that older VW tdi sound.

We put the banks muffler on it and the exhaust is nice and quite. The turbo has a nice whistle to it... there is some slight vibration when it’s cold but you have to expect that with diesels. But I don’t notice any excessive or annoying noise from it. My 4bt on the other hand was annoying after a few min of driving off-road.
 
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Chris

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I had to Edit my original post because it all depends what year and type diesel truck your referring to. The older ones are noisy in reference to engine clatter compared to the newer ones. I’d say the r2.8 is a mix between 3rd gen cummins truck and a 2004 VW tdi if you’ve heard one of those run. It’s not quite as loud as the truck and has more of that older VW tdi sound.

We put the banks muffler on it and the exhaust is nice and quite. The turbo has a nice whistle to it... there is some slight vibration when it’s cold but you have to expect that with diesels. But I don’t notice any excessive or annoying noise from it. My 4bt on the other hand was annoying after a few min of driving off-road.
Often times I'll get stuck next to a Ford F350 Powerstroke or Chevy Duramax at the stop light with my window down. It's literally unbearable, and these things are stock near as I can tell.

Of course those are huge engines, so maybe that has something to do with it. I've heard the VW TDIs, and those don't bother me at all.

I'm mostly thinking of driving with the top and doors off, and then wondering if there would be so much noise I'd lose my mind. Sounds like it would be tolerable though.
 
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1945GPW

1945GPW

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Mar 12, 2018
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They are considerably louder than gas engines for sure but that's just the nature of the beast. I've always been around diesel and jet engines so never really noticed them being super loud except when you start deleting mufflers but then again I've heard some crazy loud gas engines roaring by haha

As far as top and doors off I think the 2.8 would be just fine. When we were off roading a few weeks ago it took a few passes for this guy walking by to finally ask if it was a diesel, so I don't think its extremely noticeable other than the sound difference.
 

DieselJeep

TJ Enthusiast
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Oct 31, 2018
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KY
I think my 4.0 was louder, but it was very old. The turbo whine stands out. The first time I had it around my dad he said that wasn't a diesel. My 5.9 common rail is definitely louder, but not in the cab, but it's got sound deadening and insulation.

I just find TJs and older Jeeps to be loud in general. I've always driven with hearing protection or something to knock the wind noise down, but I'm kinda weird like that. I wear hearing protection on a road bike, because I can't hear anything with the wind, but I can with hearing protection.

Something else that was mentioned somewhere about heat around the transmission, I added a 1" BL when I swapped my engine, but when I just pulled my transmission I added some of the Noico heat or sound stuff around the bellhousing area in the tub. I did a few long drives on some hot days and my floorboard is much cooler than before the swap. It wasn't really hot outside before I pulled the transmission, so I'm not sure if it's the BL, or the noico stuff.
 

FireJeep

TJ Enthusiast
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Jan 4, 2018
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Virginia
Any more updates? Did you get the cooling issue figured out? Are you happy with what you have for the price? Thanks, such an awesome LJ...….
 

DieselJeep

TJ Enthusiast
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Oct 31, 2018
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KY
Any way you think the wiring of the fan got reversed? I had some wiring labelled incorrectly that caused some frustration.
 

disjaukifa

Kubota Diesel Wrangler Guy
Supporting Member
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Aug 1, 2018
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267
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Virginia
Great thread!!! Just got through it and it's made me realize how slow and lazy I am lol! It's neat seeing so many Cummins R2.8l swaps being done, I just couldn't afford the cost of one, otherwise I would have done it myself!

-Grant
 
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DieselJeep

TJ Enthusiast
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Oct 31, 2018
Messages
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KY
Great thread!!! Just got through it and it's made me realize how slow and lazy I am lol! It's neat seeing so many Cummins R2.8l swaps being done, I just couldn't afford the cost of one, otherwise I would have done it myself!

-Grant
Most of us had examples to look at while we're building. Your build and Mike's build for sure stand out as they're pioneering some swaps for all of us. I've got a YJ that I'm thinking will fit a Kubota nicely, so keep up the good work.
 
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DieselJeep

TJ Enthusiast
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Oct 31, 2018
Messages
520
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KY
Get it. Swap it and post about it. Video is great too.

As long as it's a responsible purchase, it's a great upgrade to how the Jeep should have been made. It's not a HP monster, but it's got what most Jeeps don't have, low end torque and MPG.
 

Little_Yellow

TJ Enthusiast
Joined
Aug 4, 2019
Messages
124
Location
Middle Tennessee
Hmm. Instead of saving for a down payment on another house, maybe I should just diesel swap my tj xD

it's really hard to argue with 25 plus miles a gallon on a vehicle I plan on driving around the country. It would ultimately save me a lot of money
 
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FireJeep

TJ Enthusiast
Supporting Member
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Jan 4, 2018
Messages
439
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Virginia
I am really wanting this as well but you would be hard pressed to recoup the money spent in milage savings..... just say'n..... all the same, this is on my future plans, probably in the spring.....