Another Cummins swap

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Topic author
boomersrule55
Posts: 16
Joined: Fri Dec 24, 2021 10:17 pm

Another Cummins swap

Post by boomersrule55 »

Hey everyone, I am currently looking into a 4BT or Cummins 2.8 swap for my 88 GW, though I am leaning towards the 4BT because I have two 12V's, one in a 95 4x4 dodge and the other in a 96 Winnebago pusher, so I have experience working on these motors. I would like to run a 4L60, 4L60e or 700R4 with a matching TC to avoid adapting to the stock GW TC, any advise on this? or how about running a 47RH with NP 241DLD behind the 4BT will it Fit? I was going to crawl under my 95 and measure it out... just want to know if anyone has tried these swaps, thanks

scout4bta
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Joined: Sat Jul 21, 2018 10:45 am
Location: Willcox AZ

Re: Another Cummins swap

Post by scout4bta »

I'm currently doing a 4BT swap into my 89 GW, using a 46RH (non lockup) from a first gen Dodge Diesel and a Atlas T-case.
I would advise against the 4L60's or the 700R4, these don't have good record of holding up behind the 4BT torque. The 47RH will work as long as it came from a behind a Diesel. The NP241DLD is a "light duty t-case, used on gas motors, Use a NP241DHD from a Diesel application.
1989 GW, Dieselize in progress

Topic author
boomersrule55
Posts: 16
Joined: Fri Dec 24, 2021 10:17 pm

Re: Another Cummins swap

Post by boomersrule55 »

Got it thanks, sounds like a 47RH will fit my swap, however I am pretty sure I have a NP241DLD behind my 95 12v, at least that's what the spec tag said when I last checked the oil and doing calcs to put a Allison 1000 in my 2500, which I abandoned and sold the Allison...anyways I was hoping to mate a 4BT to the 47RH and a TC without running thru adapters... I will crawl under my 2nd gen and check overall the length of 47RH and TC, thanks for the help.

scout4bta
Posts: 2
Joined: Sat Jul 21, 2018 10:45 am
Location: Willcox AZ

Re: Another Cummins swap

Post by scout4bta »

All you need to mate the 4BT to the 47RH is a trans adapter from a 94-98 Dodge Diesel, there may be later years that will work.
My 46RH is approximately 31 7/16" long. The Lockup TC will add about another 1" or more.
1989 GW, Dieselize in progress

Topic author
boomersrule55
Posts: 16
Joined: Fri Dec 24, 2021 10:17 pm

Re: Another Cummins swap

Post by boomersrule55 »

Ok thanks, however I am thinking of now trying to find a complete 94-95 6BT automatic 4x4 drive train, which I happen to own but I am not willing to sacrifice for this project, I will be able to crawl under there and do some math which will help. I see others have put 6BT's in FSJ's just worried about the weight and such. I have a rough country 3" lift in my shop that will be going in and will probably have to box the frame and add extra spring loading. The prices they want for a 4BT is way out there and I am not sure about the R2.8 and that rear gear cam drive.
Last edited by boomersrule55 on Thu Jan 20, 2022 9:04 pm, edited 1 time in total.
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Pablo
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Location: Arizona

Re: Another Cummins swap

Post by Pablo »

4bt's came with more than one bellhousing. What you can put behind one depends on the bellhousing you have. You can swap them. Some bellhousing are darn near unobtainable used.

I would not pay the current 4bt prices. I would look at Isuzu's in the 3.9 range from NPR trucks or investigate Cummin's newer 3.9 ISB series. Perhaps buy a whole vehicle and part it out to make your money back.

The Cummins 2.8 I hear nothing but good things, but in my opinion it is a tad bit too undersized for this application at stock power levels. I had a 2.8 sized crappy Italian diesel in a Jeep Liberty. That engine was rated at almost the same power levels stock as the Cummins 2.8, so rough power expectations can be based off it. The engine did fine in the smaller Liberty, which weighed 4200 pounds. The FSJ has more drag and when your frame is boxed, probably has the same or more weight than the Lib. When I increased the tires from 28 to 32 inch tires on steel wheels, the stock power was a bit lagging. I re-geared at the same time, but that didn't really make up all the difference. It was the added weight on the tires and wheels that took the punch out of it. I had to reprogram/tune the ECU to be satisfied with the power: boosting it from 160 HP to 190 HP and up to 360+ foot pounds. If you spend the money on the Cummin's crate 2.8, you will probably want to keep the warranty and not mess with some aftermarket tune. I think a 2.8 would work with a manual transmission for a MPG cruiser. Otherwise, too small and too under powered.

If you want a driver and RV tow rig, the 6bt could be a way to go. I would not put it in a machine you intend to offroad/wheel as it is too heavy up front and raises the center of gravity too much if you are not really careful. You are going to need stronger axles front and rear and may need to clearance / notch the firewall. Fitting a mechanical fan will require more length. I don't like how there is no room in every 6bt FSJ swap I have looked at. They look like the intake piping and motor were sandwiched in there and that you will have to take the inner and outer fenders and grill off to get to much of anything.
  • 64 FSJ Wagoneer, under the knife
  • 67 FSJ Wagoneer, peacefully taking a break
  • 94 XJ, long-armed on 33's. Bolt on ghetto fab fantastic
  • 16 BU, wife's snow commuter
Formerly: 06 KJ CRD (Constantly Repair Diesel)
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BaldBeardedBastard
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Re: Another Cummins swap

Post by BaldBeardedBastard »

Hey Boomerules55,
I have a build thread going my Cummins 2.8 build. I am going to throw my $0.02 and say that its pretty much the ideal motor for the truck.

I definitely hear what Pablo is saying about the VM 2.8( his build thread on his 4bt is a definite read), but the Cummins 2.8 is a 170 hp, 310 ft-lb motor that weighs about 40 lbs less than the original 360 I had in it. Without a regear( still on the list) and 3.31s this scoots and I am getting around 24-26 mpg highway so far(skinny pedal and trans tuning hasn't made it too terrible representative though). It is not a monster by any measure, but it is a fun reliable motor that from the crate needed 3-4 wires hooked up.

I second what Pablo is saying- it depends on what you want to do with it. Dead simple and proven? 4BT is a great choice. More modern smaller displacement? 2.8 or maybe even an EcoDiesel(?). Want to pull a mountain and upgrade axles? 6bt. Sadness and slowness? Nissan SD3.3 :-)
'86 GW Cummins 2.8/4l60E. Hopefully bouncing down a dusty road somewhere.
Build Thread

Topic author
boomersrule55
Posts: 16
Joined: Fri Dec 24, 2021 10:17 pm

Re: Another Cummins swap

Post by boomersrule55 »

Hey thanks guys for your in input, I have been actively looking at my options, and a 6bt is definitely out and a 4bt is my #1 choice like most guys, but the prices are thru the roof... I keep going back to the 2.8 and recently called cummins asking the usual questions about powering my GW, and also asked about other crate motors coming up in the future... they said there is talk about it, so if I can't something soon I will probably wait. After driving my 5.9 12V and 6.7 I am afraid I will be disappointed in the 2.8, but maybe not, I need to hitch a ride with someone who has a 2.8 in a GW and see for myself before investing 10K in a new motor. I won't be towing with the GW, just cruising around northern AZ, just want to get the waggy on the road!

Topic author
boomersrule55
Posts: 16
Joined: Fri Dec 24, 2021 10:17 pm

Re: Another Cummins swap

Post by boomersrule55 »

Hey all, just picked up the new to me 4bt from a guy who had it rebuilt by Diesel Power Services out of Birmingham AL , this guy had it rebuilt last march to put in his jeep, but abandoned the project after getting to busy with work. He brought the motor out to NM to sell, thinking there would be more jeep guys out west, so after a 1100 mi 21hr solo road trip I got it back to AZ. I talked to to the shop manager at DPS and he told me it has a new head, pistons, rebuilt injectors, rotary pump and turbo, was completely gone thru and test run for a thermostat test, hopefully this will be a good start to the project. So on to next process of gathering all necessary components before pulling the old motor. I am looking at a 47RH-NP 241 combo out of of 12V dodge if I can find one, also anyone know of good motor mount kits for the GW, I would like to run hydraulic , and a direct mount power steering kit, thanks all.

Topic author
boomersrule55
Posts: 16
Joined: Fri Dec 24, 2021 10:17 pm

Re: Another Cummins swap

Post by boomersrule55 »

I am looking to install a direct mount vacuum- power steering pump combo to go on the 4bt with ve pump, does anyone know what years will interchange, I see them on Ebay and they look the same but the years vary, thanks.

Topic author
boomersrule55
Posts: 16
Joined: Fri Dec 24, 2021 10:17 pm

Re: Another Cummins swap

Post by boomersrule55 »

Anyone know of a clutch-brake assembly that will work in 88 gw as I am going to put in a Tremac tr4050, can be aftermarket or retrofit from jeep, chevy, ford, thanks.
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Pablo
Posts: 208
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Location: Arizona

Re: Another Cummins swap

Post by Pablo »

I would re-post this question in the modified FSJ section, to get a wider audience. I bet you get 20 or more replies there and you won't get much of any here.

I am using the stock pedal assemblies from my 1964, but those are hard to come by. Maybe from a 80's manual J-truck?

I did modify the pedals to work with the newer clutch and brake setup, including having to modify the brake pedal to put a pullstyle brake light switch on it.

The firewall under there is pretty flat, so you should be able to make just about anything work on it if you have clearance to mount/route the mechanicals on the engine side of the firewall.

:fsj:
  • 64 FSJ Wagoneer, under the knife
  • 67 FSJ Wagoneer, peacefully taking a break
  • 94 XJ, long-armed on 33's. Bolt on ghetto fab fantastic
  • 16 BU, wife's snow commuter
Formerly: 06 KJ CRD (Constantly Repair Diesel)
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Pablo
Posts: 208
Joined: Sun Dec 15, 2013 6:58 pm
Location: Arizona

Re: Another Cummins swap

Post by Pablo »

boomersrule55 wrote: Wed Jan 19, 2022 10:22 am I am looking to install a direct mount vacuum- power steering pump combo to go on the 4bt with ve pump, does anyone know what years will interchange, I see them on Ebay and they look the same but the years vary, thanks.
I had one I would have sold you, but it is long gone now.

Cummins QuickServe online might be your friend here. You will need to register your engine by serial number and create an account and then you can see all the parts lookup/interchange information by serial number.

However, it is just a pump on a mount/pulley so I don't see that anyone wouldn't work with any other year as long as the mount is truly for a 4bt/6bt and not an ISB or some other newer 3.9 sized motor. You will just need a new/different belt and belt routing... It is likely that the only difference between the models you are seeing is the amount of suction they are rated to pull. I would just make sure that the one you buy has enough to run your power-brakes, or you could go hydro-boosted and run a puny electric vac pump for the HVAC controls (if you keep the stock HVAC box).
  • 64 FSJ Wagoneer, under the knife
  • 67 FSJ Wagoneer, peacefully taking a break
  • 94 XJ, long-armed on 33's. Bolt on ghetto fab fantastic
  • 16 BU, wife's snow commuter
Formerly: 06 KJ CRD (Constantly Repair Diesel)

Topic author
boomersrule55
Posts: 16
Joined: Fri Dec 24, 2021 10:17 pm

Re: Another Cummins swap

Post by boomersrule55 »

Thanks Pablo, I just picked up pedal assembly for my 95 12v dodge as I am planning to put a Tremac in that also when the 47rh goes out, the prices they want for rebuilt autos is unreal... I am just gathering parts at the moment, thanks again.

atkpilot1
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Joined: Sun May 31, 2020 7:02 am

Re: Another Cummins swap

Post by atkpilot1 »

I started my diesel swap in 2019 prior to covid in my 1991 Grand Wagoneer. Took a while to get a crate 3.0 ecodiesel. I have a 2014 Ram with the ecodiesel and don't understand why it is so hard to obtain one of these engines. And if you want one really bad and have loads of money, go to Banks.... I am using the 8 speed transmission with the Ram 1500 electronic transfer case. I am upgrading the rear axle to a DANA 60 and looking into adding airbags for a smoother ride. My 1991 was running OK, wouldn't take it on a long trip but now I am doing a full off frame restoration. Of course I am leaving the work to the pro's as if I attempted this it would never get finished! Here are some photo's of the process

I too looked into an LS, hemi or 2.8 swap. I actually got a hemi grand Cherokee to pull all the parts off of it when the call came in that I could get the ecodiesel! So I pursued this approach, and it's a jeep engine after all. The 2.8 is under powered for my needs, towing a little airstream globetrotter. The perfect setup, right?

It has been a process getting all the pieces together with supply chain issues, but it is finally underway!Image
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Pablo
Posts: 208
Joined: Sun Dec 15, 2013 6:58 pm
Location: Arizona

Re: Another Cummins swap

Post by Pablo »

atkpilot1 wrote: Sun Feb 12, 2023 1:01 pm I started my diesel swap in 2019 prior to covid in my 1991 Grand Wagoneer. Took a while to get a crate 3.0 ecodiesel. I have a 2014 Ram with the ecodiesel and don't understand why it is so hard to obtain one of these engines. And if you want one really bad and have loads of money, go to Banks.... I am using the 8 speed transmission with the Ram 1500 electronic transfer case. I am upgrading the rear axle to a DANA 60 and looking into adding airbags for a smoother ride. My 1991 was running OK, wouldn't take it on a long trip but now I am doing a full off frame restoration. Of course I am leaving the work to the pro's as if I attempted this it would never get finished! Here are some photo's of the process

I too looked into an LS, hemi or 2.8 swap. I actually got a hemi grand Cherokee to pull all the parts off of it when the call came in that I could get the ecodiesel! So I pursued this approach, and it's a jeep engine after all. The 2.8 is under powered for my needs, towing a little airstream globetrotter. The perfect setup, right?

It has been a process getting all the pieces together with supply chain issues, but it is finally underway!Image
I can't see your pics. Also, how about a link to a build thread in the build threads section? I put mine here, but they probably get more attention there. The more the merrier.

:fsj: :-bd
  • 64 FSJ Wagoneer, under the knife
  • 67 FSJ Wagoneer, peacefully taking a break
  • 94 XJ, long-armed on 33's. Bolt on ghetto fab fantastic
  • 16 BU, wife's snow commuter
Formerly: 06 KJ CRD (Constantly Repair Diesel)

Topic author
boomersrule55
Posts: 16
Joined: Fri Dec 24, 2021 10:17 pm

Re: Another Cummins swap

Post by boomersrule55 »

Update: I have been away for awhile since my last post working on building my new shop which is just about complete, the 88gw is in the shop up on stands and I pulled the stock fuel tank recently as I am putting in 25gal aluminum tank I just received from Rhodes race cars and it looks very well made, 20x30Wx10D with a built-in sump and AN weld-on fittings, it will be mounted behind the rear axle, and will I eventually need to build a spare tire carrier... the stock tank had to go because of 47rh trans and 241dld t-case were to long... Looking like I will have to use back holes on the frame, to bolt up the trans cross member, still need to change 241dld input shaft to the longer 5in as the t-case came from behind a 47re which uses the shorter 4 5/16 input... motor mounts are placed on the motor and using a combination of 2nd and 3rd gen dodge factory mounts, once I get the engine placed, I will be able to fab up the saddles and they will bolt up to the stock motor mount holes in the frame... still a lot of work to do...
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Pablo
Posts: 208
Joined: Sun Dec 15, 2013 6:58 pm
Location: Arizona

Re: Another Cummins swap

Post by Pablo »

Awesome. Always more work to do.
  • 64 FSJ Wagoneer, under the knife
  • 67 FSJ Wagoneer, peacefully taking a break
  • 94 XJ, long-armed on 33's. Bolt on ghetto fab fantastic
  • 16 BU, wife's snow commuter
Formerly: 06 KJ CRD (Constantly Repair Diesel)
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