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Thinking about going Cummins 4BT

ebertf

ebertf

Active member
City
Soldotna
State
AK
I ran across a deal on a Cummins 4BT coming out of a CJ7 I'm thinking about putting in my Alaskan Postal. It has a built th350 with a custom toque converter 80 HP injectors and a modified A pump. Turn key package. what is everyone's' thoughts? Jeep (10000).jpg
 
Have you ever been around a 4BT? Have you driven them? Are you a diesel enthusiast? If so and you love the engine it isn't a bad choice.

I've been around them a bit. They are a quite noisy and can have some vibration issues that would create quite a drone in the postal top. They have some pretty serious drawbacks. A 4BT weights around 800 lbs and the height causes packaging issues. They make very little power in stock form. I would look into Mercedes, VW or the Cummins R2.8 if dead set on diesel power.
 
sdsupilot said:
Have you ever been around a 4BT? Have you driven them? Are you a diesel enthusiast? If so and you love the engine it isn't a bad choice.

I've been around them a bit. They are a quite noisy and can have some vibration issues that would create quite a drone in the postal top. They have some pretty serious drawbacks. A 4BT weights around 800 lbs and the height causes packaging issues. They make very little power in stock form. I would look into Mercedes, VW or the Cummins R2.8 if dead set on diesel power.
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I CAN NOT FATHOM what the vibration and sound from a 4BT would be like inside the World Cab.

I've been in and driven 4BT Jeeps, they're cool if that's what you're into, but there isn't any way in this world I would put one in a Postal that you intend to keep the top on and drive with any regularity.

I'm thinking something like a vibrating steel drum band going nonstop.

I am 100% with @sdsupilot on the R2.8 suggestion if you want to go that route.
 
sdsupilot said:
Have you ever been around a 4BT? Have you driven them? Are you a diesel enthusiast? If so and you love the engine it isn't a bad choice.

I've been around them a bit. They are a quite noisy and can have some vibration issues that would create quite a drone in the postal top. They have some pretty serious drawbacks. A 4BT weights around 800 lbs and the height causes packaging issues. They make very little power in stock form. I would look into Mercedes, VW or the Cummins R2.8 if dead set on diesel power.
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I have driven a number of 5.9 (6BT) Cummins never a 4BT The fuel econ and no (little) electronics is interesting to me it is 200 lbs. over the 258 at 500lbs vs 4BT 700 Lbs. this is an Alaskan winter driven rig so the added LBS is a plus on ICE especially with studded tires. The turn key package is $3500.00 so that is why I'm looking at it. It seems like a good deal vs $2000.00 -$3K for a reman 258.
 
If the engine is in good shape that sounds like a great package price.
 
I had a TJ with 4bt On 35s. Got 25mpg. Not a power house but once I got going I barely had to shift out of 4th gear with the torque it had. Yes, biggest issue was vibration at a stop. The whole Jeep shook. The coolmfactor wore off and I sold it
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mwqpd11 said:
Yes, biggest issue was vibration at a stop. The whole Jeep shook.
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This is exactly what I was talking about. Imagine all the sheet metal of the World Cab surrounding you when that was happening...

@ebertf are you keeping the insulation in the top or is it peeled out? That would help, I suppose, but the thing with the insulation is that it shed little particles that felt like razor blades when they got in my eyes. I always wore sunglasses when driving for that reason before I got the insulation out. The vibration from the 4BT could really shake bits loose.
 
bigwalton said:
This is exactly what I was talking about. Imagine all the sheet metal of the World Cab surrounding you when that was happening...

@ebertf are you keeping the insulation in the top or is it peeled out? That would help, I suppose, but the thing with the insulation is that it shed little particles that felt like razor blades when they got in my eyes. I always wore sunglasses when driving for that reason before I got the insulation out. The vibration from the 4BT could really shake bits loose.
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I'm pulling the insulation and going with some sound damping material. Then if I have enough ambition fab up some removable insulated interior panels. Not as ugly or hard to remove as the spray foam. More on the line of the Overlander Scrambler but without the windows.
 
Would that use the stock Dana 300 transfer case? Driveshaft clearance can be an issue with GM automatics. Coming from a running/driving CJ the install would probably be relatively easy. I would also love watching this being built. Let us know what you decide to do.
 
I'd really want more trans OD than a th350 gives... with a 4BT, just to stay in the torque curve.

I've driven 4bts, 6bts, 6CTA's etc. They will vibrate your teeth out, above 1450 RPM
 
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