Official Cummins 4BT Swap Thread for CJ's
This is the Official Cummins 4BT Swap Thread for the Jeep CJ's
Okay, should I call this another 4.0 swap? Nope, it's a 3.9L and it smells like diesel! Before I get too far in depth with this thread, I'll first run through the highlights of my 4BT swap:
The Engine
I'm sorry to be so blunt, but anybody with a brain that does any research will always come back to Cummins when they are looking for a strong diesel engine to put into their Jeep.
My 4BT (4=4cylinder, B=B series, T=Turbo)
is factory rated at 105hp and 265ft/lb torque with a 17.5:1 compression ratio weighing in at about 700lbs.
The 4BT is the exact same Cummins engine as the first generation Dodge Ram Diesels 6BT except with the front two cylinders chopped off. Therefore all the Dodge Ram Cummins 6BT parts are interchangeable with the 4BT.
http://i209.photobucket.com/albums/bb130/BigTorquer/Top.jpg
Mounts
As far as I know, there is nobody out there that makes an aftermarket 4BT to CJ frame engine mount kit. I constructed my own and they can be seen here:
http://i209.photobucket.com/albums/bb130/BigTorquer/Picture16.jpg
http://i209.photobucket.com/albums/bb130/BigTorquer/Picture15.jpg
http://i209.photobucket.com/albums/bb130/BigTorquer/Picture14.jpg
I used polyurethane AMC V8 motor mounts and built the brackets myself.
Transmission
This is where it gets fun: everything here is built for the 6BT, so what I'm implying is that it is all huge and super heavy duty because it was built to handle the 6cyl with twice the power of the 4BT.
As far as transmissions go I have always preferred my manual trannies, so as Auto trannies go: I won't be much help.
I was fortunate to have a Dodge NV4500 in my Jeep previous to this swap. All I had to do to connect it to the 4BT was buy the following from Dodge:
1. Flywheel Housing
2. Flywheel
3. Clutch
4. Pressure Plate
5. Bellhousing with clutch release bearing
6. and all the small parts and bolts to put them all together.
I did have to put a heavy duty input shaft on my NV4500 to match the massive clutch.
Transfer-case
I already had my Dana300 with 4:1 mated to my NV4500. Nice case, so no upgrade needed here.
Cooling
I use my stock (heavy duty) radiator for an AMC V8 and have no overheating issues. I also have a 14inch Mr. Gasket electric cooling fan mounted to it.
Exhaust
I towed my CJ to the exhaust shop and had them bend up a nice 3in exhaust with nice Magnaflow muffler.
Alternator/Starter
The alternator that comes with the 4BT is a Delco-Remy SI series High-output alternator that is significantly larger than the D-R alternator that comes with the CJ originally. I had mine rebuilt and it is super nice and powerful!
I have a starter for the Dodge Ram Diesel; so as you can imagine, I expect it will last for a long time. http://i209.photobucket.com/albums/bb130/BigTorquer/Picture17.jpg
Wiring
Taking for granted that you can wire up a starter and an alternator (two things you should already have anyway) all you need to run the 4BT is one wire! The diesel has a fuel shut-of solenoid that must be powered up to open the fuel system to the pump. Therefore a "key-on" power wire (your existing "ignition" wire) is necessary to start and shut-off the engine.
Brake Booster
Since you lose the vacuum capability with running the Diesel engine, I decided to go Hydroboost.
I bought a hydroboost setup from a Dodge Ram Diesel. I had to make some custom brake lines to attach to my proportioning valve, but boy is it powerful!
http://i209.photobucket.com/albums/bb130/BigTorquer/Picture5-1.jpg
I'll continue to add to this thread to provide some more complete info on my swap. Meanwhile, enjoy some videos that I made: http://www.youtube.com/user/ManheimDiesel
For an unlimited pool of info from many many people that have done 4BT swaps I recommend visiting the 4BT Swaps Forum at: http://www.4btswaps.com/forum/index.php
This is the Official Cummins 4BT Swap Thread for the Jeep CJ's
Okay, should I call this another 4.0 swap? Nope, it's a 3.9L and it smells like diesel! Before I get too far in depth with this thread, I'll first run through the highlights of my 4BT swap:
The Engine
I'm sorry to be so blunt, but anybody with a brain that does any research will always come back to Cummins when they are looking for a strong diesel engine to put into their Jeep.
My 4BT (4=4cylinder, B=B series, T=Turbo)
is factory rated at 105hp and 265ft/lb torque with a 17.5:1 compression ratio weighing in at about 700lbs.
The 4BT is the exact same Cummins engine as the first generation Dodge Ram Diesels 6BT except with the front two cylinders chopped off. Therefore all the Dodge Ram Cummins 6BT parts are interchangeable with the 4BT.
http://i209.photobucket.com/albums/bb130/BigTorquer/Top.jpg
Mounts
As far as I know, there is nobody out there that makes an aftermarket 4BT to CJ frame engine mount kit. I constructed my own and they can be seen here:
http://i209.photobucket.com/albums/bb130/BigTorquer/Picture16.jpg
http://i209.photobucket.com/albums/bb130/BigTorquer/Picture15.jpg
http://i209.photobucket.com/albums/bb130/BigTorquer/Picture14.jpg
I used polyurethane AMC V8 motor mounts and built the brackets myself.
Transmission
This is where it gets fun: everything here is built for the 6BT, so what I'm implying is that it is all huge and super heavy duty because it was built to handle the 6cyl with twice the power of the 4BT.
As far as transmissions go I have always preferred my manual trannies, so as Auto trannies go: I won't be much help.
I was fortunate to have a Dodge NV4500 in my Jeep previous to this swap. All I had to do to connect it to the 4BT was buy the following from Dodge:
1. Flywheel Housing
2. Flywheel
3. Clutch
4. Pressure Plate
5. Bellhousing with clutch release bearing
6. and all the small parts and bolts to put them all together.
I did have to put a heavy duty input shaft on my NV4500 to match the massive clutch.
Transfer-case
I already had my Dana300 with 4:1 mated to my NV4500. Nice case, so no upgrade needed here.
Cooling
I use my stock (heavy duty) radiator for an AMC V8 and have no overheating issues. I also have a 14inch Mr. Gasket electric cooling fan mounted to it.
Exhaust
I towed my CJ to the exhaust shop and had them bend up a nice 3in exhaust with nice Magnaflow muffler.
Alternator/Starter
The alternator that comes with the 4BT is a Delco-Remy SI series High-output alternator that is significantly larger than the D-R alternator that comes with the CJ originally. I had mine rebuilt and it is super nice and powerful!
I have a starter for the Dodge Ram Diesel; so as you can imagine, I expect it will last for a long time. http://i209.photobucket.com/albums/bb130/BigTorquer/Picture17.jpg
Wiring
Taking for granted that you can wire up a starter and an alternator (two things you should already have anyway) all you need to run the 4BT is one wire! The diesel has a fuel shut-of solenoid that must be powered up to open the fuel system to the pump. Therefore a "key-on" power wire (your existing "ignition" wire) is necessary to start and shut-off the engine.
Brake Booster
Since you lose the vacuum capability with running the Diesel engine, I decided to go Hydroboost.
I bought a hydroboost setup from a Dodge Ram Diesel. I had to make some custom brake lines to attach to my proportioning valve, but boy is it powerful!
http://i209.photobucket.com/albums/bb130/BigTorquer/Picture5-1.jpg
I'll continue to add to this thread to provide some more complete info on my swap. Meanwhile, enjoy some videos that I made: http://www.youtube.com/user/ManheimDiesel
For an unlimited pool of info from many many people that have done 4BT swaps I recommend visiting the 4BT Swaps Forum at: http://www.4btswaps.com/forum/index.php