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Cummins Swap

1K views 7 replies 6 participants last post by  JakeDiesel 
#1 · (Edited)
I have a friend that is big into building vehicles that make you say, "Did I really just see that?" Bobby started doing 12V Cummins swaps into Chevy pickups in the mid-90's. His first one was a 84 or 85 Chevy that got a 12V and a Getrag 5 speed. Bobby has since done quite a few 12V swaps into various Chevy's, preferring the '93 and newer Chevy's for their cushy ride quality, good looks and durability.

Recently, Bobby bought an '04 (IIRC) Chevy 3500 4x4 cab & chassis with a blown up Duramax and a good 6spd, and 3.73 gears in the axles. He retrofitted a flatbed he had sitting around onto the truck, and dropped in a SBC 400 gas engine. Well, he found that the engine would loaf along at 2100RPM at 70MPH, but the 400 was only getting 4-6mpg pulling the truck. Combine Bobby's love of the unique with the truck's gearing, and he realized that the only option was to drop a Cummins in. I love wrenching, so naturally, I volunteered to help Bobby with the swap. The question at this point became, "What motor are we going to swap in this thing," as Bobby always has 4 or 5 good 6BT's sitting around waiting for a new home. Recently, though, Bobby acquired a 4BT with a Chevy adapter. Basically, we flipped a coin, and decided that he should give the 4BT a chance to prove itself.... Here are some pictures (taken kind of late in the project, because I'm an idiot and forgot my camera)









I apologize for the sideways picture. It is upright in my photobucket account, but it doesn't seem to be cooperating here. Pointers?

I'll snap some more pictures as we get it put back together, and I'll let ya'll know how it runs
 
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#3 · (Edited)
haha right on. not sure about using the 4bt though, i think i would have kept the 4bt for something a little more light duty (be perfect for a lil 1/2 ton or even something smller), i wouldnt expect to see amazing milage out of it in a big ol heavy truck.

Is he planning on doing any modifications to the engine? stock 4bts are far from being a powerhouse!

maybe a p-pump swap? :D

If you havent seen southbends 4bt, go to their website and check it out (i believe the video is under the dodge clutch section), that is one crazy 4bt!


Is he planning to debadge the truck, or leave the dmax badges and see how many people scratch their heads looking at it? :hehe:
 
#5 ·
haha right on. not sure about using the 4bt though, i think i would have kept the 4bt for something a little more light duty (be perfect for a lil 1/2 ton or even something smller), i wouldnt expect to see amazing milage out of it in a big ol heavy truck.

Is he planning on doing any modifications to the engine? stock 4bts are far from being a powerhouse!
The plan is to run it with any minor/free mods he can swing for the motor. Bobby doesn't intend on pulling much weight with it, at most a Bobcat around town. And if he isn't satisfied with the power/driveability, he's got a 6bt that's ready to drop in. This is a "I wanna see how it works out" test project. :thumbsup:

Is he planning to debadge the truck, or leave the dmax badges and see how many people scratch their heads looking at it? :hehe:
No, the plan is to take the crappy little durasux badges off, and replace them with proper Cummins Power badges..... :headbang:
 
#6 ·
3 Month Update

Bobby has been running the 4BT for about 3 months with mixed feelings.

The Good:
16-17MPG average mixed in town & highway driving
20+ MPG average highway driving
Will run 70MPH, even pulling a trailer

The Bad:
Turbo is WAY too small for the motor
Takes all day to get to 70MPH, even empty

Bobby has pretty well decided that swapping in a bigger turbo is going to be a pain, as he'll have to find another exhaust manifold, flip it and re-work all the turbo plumbing. We've also figured out that 3200RPM governor springs did nothing to help at all.

The plan is that we will probably be yanking the 4BT out here in the near future and replace it with a 6BT sometime in the next few months. The 4BT will probably go into a much lighter truck (the dually weighs in at 7500lbs with a full tank because of the bed) I'll be sure and get a bunch of pictures before we pull the 4BT, and also of the 6BT swap
 
#7 ·
Very cool swapp.
 
#8 · (Edited)
Im with dave would have save the 4bt for something a little smaller, yes the 4bt can handle it but you would get the mpg and its not goin to be very fast. the 4bts can hold up nice with power up grades, there are some out there as daily drivers with 350hp.
other than that nice work, swaping a cummins in a duramax is not any easy swap.
 
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