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Diesel in a CJ7

S

Spicy_Red

Everythin'sBroke
Does anyone know of, or tried to put a diesel engine in to a CJ? If so what one would I be looking at or where would I start to look? I have a 76 CJ7 that I am working on but still have a few bugs to work out like what engine should I put in it since the one I have is blown. I was looking at a deisel because I have ready access to fryer oil and figured why not take another step towards being nature friendly.

Any input would help as well as telling me I am crazy for even thinking it if that is the case.

Thanks

RED
 
motorizedanarky

motorizedanarky

Member
Location
earth
well its not out of the relm of possiblity
first need an engine electrics then the propper tank and pump no biggie you be making mounts
however if you are thinking veggie oil fryer oil unless you plan on heating the entire fuel sytem it sucks when its cold pretty strieght forward swap to me any way
 
Greg

Greg

I run a tight ship... wreck
Admin
Location
Grand Junction, CO
Yes, Cummins 4BT. It's a 4 cyl Cummins, is quite heavy but a good replacement for 6 cyl and V8 gas engines. You can run a NV4500 5 speed or NV5600 6 speed from Dodges or there are adapters to mate them to the popular GM automatic transmissions. There's plenty of other transmission options out there too.

You can find 4BT's for around $2500, the cost to do the actual swap will probably run you more than the motor itself, when you get everything in and running. You'll probably need a good bit of lift to clear the oil pan, as the motor is very tall.

The 4BT makes about 300 ft/lbs stock and can easily be turned up for 400 ft/lbs. In a Jeep CJ that motor will probably get 26-28 MPG.


Here's my diesel project- http://www.rockymountainextreme.com/showpost.php?p=535771&postcount=42

If you want some good diesel swap info, check out 4BTSwaps.com. I know there's several people who have swapped 4BT's into CJ's, YJ's and TJ's.
 
Tacoma

Tacoma

Et incurventur ante non
Location
far enough away
There was a guy in the old comps that had a diesel in a CJ7, and I think it WAS a 4bt.

Not a bad choice, limited powerband, and they're like a heavy big block.
 
Greg

Greg

I run a tight ship... wreck
Admin
Location
Grand Junction, CO
Tacoma said:
There was a guy in the old comps that had a diesel in a CJ7, and I think it WAS a 4bt.

Not a bad choice, limited powerband, and they're like a heavy big block.
Click to expand...

You can get a 3200 RPM spring and up the max RPM. That combined with stock axle gearing and bigger tires makes for a great driveability combo.
 
S

Spicy_Red

Everythin'sBroke
Greg said:
Cummins 4BT. It's a 4 cyl Cummins, is quite heavy

You can find 4BT's for around $2500, the cost to do the actual swap will probably run you more than the motor itself, when you get everything in and running. You'll probably need a good bit of lift to clear the oil pan, as the motor is very tall.
Click to expand...

any idea on how heavy it is?

I would like to try to do the swap myself to avoid paying for it although my competence in doing so would be tested hard.

has anyone built a cage to help protect the oil pan or would the lift be the only real option? I would think both but I would't want to be to tall since I would like to keep it on the street also (at least sometimes)
 
Tacoma

Tacoma

Et incurventur ante non
Location
far enough away
Greg, just saw the oil pan issue in your post. I can't recall seeing one (but I wasn't looking, either), but there are a ton of applications for the 6bt, and some of them use smaller pans. So it's worth looking into the alternatives in the Cummins catalog. I found a pretty sweet lower profile 6bt pan, waiting on price and angularity issues. :D
 
Greg

Greg

I run a tight ship... wreck
Admin
Location
Grand Junction, CO
Spicy_Red said:
any idea on how heavy it is?

I would like to try to do the swap myself to avoid paying for it although my competence in doing so would be tested hard.

has anyone built a cage to help protect the oil pan or would the lift be the only real option? I would think both but I would't want to be to tall since I would like to keep it on the street also (at least sometimes)
Click to expand...


I think it's 650-700 pounds running. You may need custom built front springs to support the motor.

Have you done any motor swapping before? The Cummins 4BT is a simple motor, hardly any wiring involved. You would need to weld in motor mounts and figure out a transmission mount, along with lots of other small stuff. It could be a really good learning experience too.

The problem with the oil pan isn't ground clearance, but the depth of the motor versus where the front axle sits. You will probably need 4" of lift between the axle and frame to fit that motor. 4" lift on a CJ isn't too extreme, I think it's within reason.
 
Greg

Greg

I run a tight ship... wreck
Admin
Location
Grand Junction, CO
Tacoma said:
Greg, just saw the oil pan issue in your post. I can't recall seeing one (but I wasn't looking, either), but there are a ton of applications for the 6bt, and some of them use smaller pans. So it's worth looking into the alternatives in the Cummins catalog. I found a pretty sweet lower profile 6bt pan, waiting on price and angularity issues. :D
Click to expand...

Probably are options, for my application I want the 4" of lift so I can fit 35's to get the final gearing right. The oil pan isn't an issue for me. If someone wanted to get creative and spend lots of $$ they could build a oil pan that hugged the internals and setup a dry sump system.
 
Tacoma

Tacoma

Et incurventur ante non
Location
far enough away
You could definitely cut/weld the stock pan for more clearance. Cummins engines are tall motors. The pickup system looks pretty easy to modify, too.
 
S

Spicy_Red

Everythin'sBroke
Greg said:
I think it's 650-700 pounds running. You may need custom built front springs to support the motor.

Have you done any motor swapping before? The Cummins 4BT is a simple motor, hardly any wiring involved. You would need to weld in motor mounts and figure out a transmission mount, along with lots of other small stuff. It could be a really good learning experience too.
Click to expand...

I haven't done an engine swap before although the mechanic that works for my uncle said he could help me with it if I needed help (I haven't told him I was thinking about going with a diesel yet)

I like to learn about what I'm running so that if I break it I might be able to fix it in a pinch, plus I don't like to pay for something I can do myself unless the mechaninc lets me sit in with him and learn.

I really haven't delt with any diesel engines before so everything would be new to me.

I will hopefully have a spot in my uncles shop to do the work but not sure yet. If I get a spot there then I would be looking at a frame up rebuild that way I can re-position the mounts or figure out new ones pretty easy

I was looking at a 4 inch to 6 inch lift anyway so it is good to know that the clearance won't be an issue for that.

The weight is slightly worrysome though I will have to figure out a few things for axles and engine so I am not too heavy but it is one to figure out.

I appreciate the info alot .
 
RockMonkey

RockMonkey

Suddenly Enthusiastic
Tacoma said:
There was a guy in the old comps that had a diesel in a CJ7, and I think it WAS a 4bt.

Not a bad choice, limited powerband, and they're like a heavy big block.
Click to expand...

Did he call it the Green Hornet, or the Killer Bee, or something like that? I think I saw it on fire in Farmington once.
 
RockMonkey

RockMonkey

Suddenly Enthusiastic
Greg said:
You thinking about the one that had the Mazda Rotary motor? I think it caught fire... had a very, uhh... distinctive... sound. :ugh:
Click to expand...
Yeah, that's probably what I was thinking of. Just remembered it had a different motor, and it was on fire. I was just sitting here thinking it must not have been diesel, since the stuff doesn't burn... :ugh:
 
Rot Box

Rot Box

Diesel and Dust
Supporting Member
Location
Smithfield Utah
My vote are the V8 6.2 or 6.5 GM diesels (I can't be serious right? :ugh:) second to the 4BT.

The 6.2/6.5's can be found in almost any fullsize GM vehicle made from 82-00 (and still found in AM General's Humvee's) they are everywhere! Non turbocharged they are a little short on power, but with the CJ's weight I think you'd be okay. They will bolt up to almost every V8 GM bellhousing, and are fairly lightweight.

There are certain years to avoid for reliability issues (ask me how I know! :rolleyes:), but for the most part they were very reliable. Mechanical injection up to 93 means wiring is a breeze and SVO/WVO can be ran reliably.

Search here for more info http://thedieselpage.com/ There are several members here that have these engines in everything from Landcruisers to Jeeps.

Just a thought,

Andrew
 
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