Been thinkin more seriously about picking up a 4BT off this guy on CL...selling a supposedly checked/tuned good-running rotary pump 4BT with Ford trans shipped for $2900. Ideally I'd like to find a halfway decent (or at least possible to be made so without an act of god) CJ5 or CJ7 to swap it into but that's gonna depend on what I can find, would consider a Wrangler if it feels right.

Just trying to make a good ol' ugly fuckin-around truck for some mud, beach, snow days, mild crawling maybe. I'm handy in the garage but I've never done a full motor swap, nor have I ever owned a Jeep. I have a 2nd-gen 12V so the motor won't be entirely unfamiliar, at least. I know lots of people have done this swap, figured one of you had or would at least know what I'm getting myself into.

I know the general process but any particular advice y'all could offer would be much appreciated.


for example, offer $1500 on this rolling frame http://eastnc.craigslist.org/cto/4424816000.html
with $2900 for one of these http://stores.ebay.com/cummins4bt?_trksid=p2047675.l2563
=$4400 for a rough-in CJ5/4BT?


[Edited on April 16, 2014 at 6:37 PM. Reason : donny you're out of your element]

4/16/2014 6:16:33 PM

i'd love to have one in a dakota

that is all

4/16/2014 6:44:52 PM

hey, look http://www.4btswaps.com

4/16/2014 6:45:59 PM

I've seen them in wagoneers online. Any of the mentioned would be cool. I'm kinda surprised the weight/torque/wheelbase combo in a cj5 isn't an issue.

4/16/2014 7:28:00 PM

seems like a waste to me

4/16/2014 7:29:52 PM

In my experience, diesel swap gets old real quick . Even with the venerable lil Cummins, once you find the limitations of a 4cly diesel it gets boring.

4/16/2014 9:07:42 PM

Yeah .

My thoughts are :

More horsepower elsewhere
Eve the 4bt is heavy
When 4 wheeling thrift tke response is important

I really want a 6bt in something despite all these facts.

It's smarter to (gasp) put a 5.3 swap with a turbo... Stock crate motor is cheap as balls and I've seen them boosted to 650hp without taking the heads off.

4/16/2014 9:35:15 PM

Well my other motivations were fuel economy and reliability/maintenance. Right now my daily driving is split between my bike and truck, I'd like to prolong the life of the Chrysler elements of the latter by sharing the load with a (marginally) more reasonable DD than a one ton dually. People seem to be regularly getting 25-30+ mpg out of the 4bt, and I know it'll last.

Besides, I don't ever plan on buying a gas motor again if I can get away with it, unless I want it for pure performance reasons (or its a V-twin ). 4BT in a CJ seems like a good combo that can provide a solid mix of reliability, lowish cost of ownership, ease of maintenance as well as some good times as mentioned.

So, unless there's something egregiously wrong with that I'm fairly certain that's direction I'll go. What particular limitations do you speak of that could make me regret the decision?

[Edited on April 17, 2014 at 5:38 AM. Reason : ffff]

4/17/2014 5:28:52 AM

If you put a fork lift rig on the back of a cj with that 4bt in, you might have a good red neck fork lift. Otherwise, i see no point in adding a ton of weight to the front of a short wheel base jeep? on D30 axles? why? Also, all that weight in the front of a cj will bury itself on the beach.

I like the diesel swap idea, but cj's in general make lousy DD's. If you really want a DD, get something that at least has AC/Heat and less noise. The waggy option is better, or one of the old j series trucks. K5 blazer with original diesel option or swap would be better too.

4/17/2014 7:06:04 AM

If you're just looking for a good putt-putt vehicle, go for it -

we've discussed it before (foo1 and I) but you've got a significantly smaller power band with a diesel that affects your available wheel speed in any gear.


the decision I would make (and honestly join the swap forum or a cummins-related forum), is whether you want an inline p-pump (static injection timing) or a rotary pump (dynamic injection timing). The rotary would probably have better 'general' performance characteristics, however the P-pump would respond to modifications better.

4/17/2014 7:09:11 AM

Why go through the trouble and expense of this? Doesn't seem worth it. Instead spend $3000 on an old Civic or Corolla if you need another vehicle to share the DD mileage load.

4/17/2014 8:16:21 AM

I read the OP's posts as:

"I want to do a diesel conversion - I will also probably DD it since the engine will be easy on fuel consumption"


...although, barring fuel cost, I would just DD the 12V.



But, hey, let's not shit on a guy taking on a project! Go for it.

4/17/2014 8:34:27 AM

what about the old K5 military blazers? For the price of your 4bt you could have a running, serviceable truck (ready to play) and would only need to figure out how to stuff a turbo under the hood instead of an entire engine.

Note: I know jack about these motors or how abused some of these blazers might be.

4/17/2014 9:40:59 AM

I'm all for this idea, but i would just say to see ifyu cna track down someone that has done the swap and see how they like it. For your mostly street driving requirements it will probably be good to go, but i know of a couple of people who have swapped them, kept them a year or less, and ended up with an LS v8.

also, i would take you budget and add at least another 3-4k. adapting or swapping the t case and drive shafts can easily run close to 2k for a reliable streetable setup. i would budget for totally rebuilding front axle and steering, and brakes. these jeeps are all over the road even with new components.

$300 for a shifter, exhaust, etc, this shit really adds up fast. hell, i might budget 5k for the swap.


[Edited on April 17, 2014 at 10:00 AM. Reason : $$$$]

4/17/2014 9:51:04 AM

^^^ that's pretty much it, in better words than I used. Unless there's a better "small" diesel + topless 4x4 combo I should be looking into

[Edited on April 17, 2014 at 11:03 AM. Reason : carat]

^^ hadnecven thought abt it, ill look into it...doubt fuel econmoy woukd work out though

^ isure you're right...that's the sort of stuff inm looking for here. Will have. Afew more questions later when off work

[Edited on April 17, 2014 at 11:06 AM. Reason : fuckin blackberry]

4/17/2014 11:02:17 AM

BLACKBERRY????

ALso, I missed the rotary pump part in the OP. is that a 4R100 trans?

Have you considered a 1/2-ton truck swap with the 4bt? how's about an old pickup? that would be much more suited, and so long as you set that puppy as far rear as possible the handling would be pretty good....considering.

4/17/2014 11:26:30 AM

Haha yeah, work phone...

I want the open cab of a jeep and I'm nowhere near the fabricator skill level required to make a removable roof and doors out of a half ton truck. So it doesn't necessarily need to be a jeep, but it needs to be like a jeep. Figured I'd just go with a jeep. Are there any other common smaller diesels out there worth a shit I could be looking at besides the 4bt? Is the 4bt really gonna fuck the weight distribution up that bad?

[Edited on April 17, 2014 at 3:29 PM. Reason : I can't tell what the transmission is from his pics but it doesn't look like a 4R100 to me]

4/17/2014 3:23:04 PM

there are a few options, none of which am I familiar. Primer did a diesel swap in a LR a while back....

4/17/2014 3:27:24 PM

Oops thought I was editing but I was really re replying

[Edited on April 17, 2014 at 3:30 PM. Reason : Moron]

4/17/2014 3:27:49 PM

750lbs of front end weight... My all cast iron big block weighed less than that.

Answer: yeah on a jeep it's gonna get wonky.


Scrambler/early bronco/scout?

Jeep made that common rail diesel in the early 2000s that might work.

4/17/2014 3:30:00 PM

^good insight


I hate to say.... have you considered a 2.5L TJ?

[Edited on April 17, 2014 at 3:33 PM. Reason : ......save the money, get decent mileage]

4/17/2014 3:32:52 PM

scrambler would be tits if I could find a decent rolling frame for the right price, and I've always had a soft spot for broncos. scout would be a little hefty for what I want, I think.

think a 4BT + scrambler would work out?

4/17/2014 3:35:35 PM

Quote :

"I hate to say.... have you considered a 2.5L TJ?"

my gf already has a forester

4/17/2014 3:37:14 PM

^^^ do the 2.5s really get better mileage than the 4.0s? ive heard mixed things on that.


also,according to the internet an AMC 258 weighs in around 500, an AMC304(available in cjs) weighs in around 600, and 4bt weighs in around 750(wet weight)

150lb isnt going to make or break a swap, even on a short wheelbase jeep.

http://cumminsengines.com/showcase-item.aspx?id=146&title=B+Series+for+Construction+%28Tier+2%29&Filters=0&SearchText=b+series#specifications


Also, most of the 4bts i see for sale with auto trans have a TH400 2wd trans.


[Edited on April 17, 2014 at 3:44 PM. Reason : h]

4/17/2014 3:39:53 PM

Jeepman has a 2.5..... PEANUTTTTTTTTT


so, anyway adam makes a good point.

if you do get, I'd go with an SAE bellhousing and a 47RH transmission, with an NP241 t-case behind it. you can get a good core 47 for $400, and a rebuild done for around $350 in parts

4/17/2014 4:09:55 PM

yeah there are a ton of 4bt/Jeep swaps, I'm sure the novelty has a lot to do with that but I can't believe it's all that bad...like I said, I'm not going to be doing anything too serious with it. Most I'm worried about is a nose-dive into the sand. Had to tuck my tail between my legs and ask a guy with a chevy avalanche to pull my 12V out of a ninja sand pit one time, that front end just sunk like a rock...don't want to have to do that again

4/17/2014 4:15:24 PM

Quote :

"I'd go with an SAE bellhousing and a 47RH transmission, with an NP241 t-case behind it."

Thanks, I'll look into this...any recommendations for a manual? I wouldn't put an auto in this

4/17/2014 4:18:40 PM

not sure if there are custom brackets for other transmissions, but I'd put the nv4500 at 'fuckin heavy', although it will fit the same adapter (with the dodge bellhousing). I think that thing is like 100# heavier than the 47RH

4/17/2014 4:25:11 PM

well I'll just have to trim down then

thanks, gonna do some more research. will report back with more awesomely impractical ideas

4/17/2014 6:10:24 PM

yeeeeeeeeehaaaaaaw http://charlotte.craigslist.org/cto/4336426696.html

4/17/2014 9:10:20 PM

Awww fuck yeah

4/19/2014 1:21:54 PM

Only problem with scramblers is the other jeep guys get a little jealous.

4/20/2014 2:40:13 PM