4BT Cummins

[Ziegelsteinfaust]

My friend has been on me to do a Cummins Swap in my C10 since I wounded the motor doing donuts. I have been diesel curious for quite awhile, but never felt the need to pull the trigger. Yet I ocassionally look at swaps when I am bored at work. Since I work graveyard I have a bit of time.

So why do some people say the 4BT can not handle the same big power upgrades a 6BT can? Is this because it is not as balanced with the 4 cylinders vs 6?

Also some people in a 2wd truck claim low 30's highway, and other's say anything above mid 20's is lying? Any opinions on who is right?

One build that had me interested is a guy who used a 8hp75 with Eco-diesel torque converter combined with a proper rear gears. Said he should be at 1700rpm at 75 for maximum cruising plus have a wide ratio transmission to have a good mpg at any speed. I believe it was going into a lowered D100.

Any thoughts?

Just trying to learn from peoples experiences.

[scottofksu]

I would assume weight would be your biggest issue as even the 4bt - to say nothing of the 6bt - is over 200lbs heavier than a SBC. The primary issue would be the longevity of the steering components and brakes as well possibly. I have a 6bt in my 2001 Dodge 2500 that weighs close to 8,000lbs. With tiny little 235 mud tires and driving around 55 MPH over 3-4 mountain ranges from Washington state to Omaha, Nebraska I achieved an average of 23MPG and that was with the engine leaking boost like crazy. I can tell you the 6BT likes a little RPM - I find my best mileage occurs when I hover just under 2,000 RPM. At <1,700 it lugs a bit and the 4 speed often starts searching for another gear if you give it any gas. Gearing will be a huge consideration. That said, it is the best engine I have ever owned, and I just try not to turn the tires when stationary to save my steering components a bit of strain especially given I am now running true 35" tires on the Dodge.

[LS short box]

My .02?
Not knowing what your long term plans are for the truck anything but Chevrolet SBC/BBC or LS engine the 4bt is going to kill the value of your truck.
A properly built SBC will sneak up on 20 mpg with a OD trans. With a LS you can get low 20 mpg with a OD trans. My 68 C10 with a LS6/T56 swap 20-22 mpg on the highway day in day out.
Again just my .02.

[Ziegelsteinfaust]

Originally Posted by LS short box

My .02?
Not knowing what your long term plans are for the truck anything but Chevrolet SBC/BBC or LS engine the 4bt is going to kill the value of your truck.
A properly built SBC will sneak up on 20 mpg with a OD trans. With a LS you can get low 20 mpg with a OD trans. My 68 C10 with a LS6/T56 swap 20-22 mpg on the highway day in day out.
Again just my .02.

I am currently swapping a L98 long block in to "restore" the truck to a stock appearing simple ride. Then hopefully sell around the end of summer.

But why would a 4bt kill value? It looks like there is a big enthusiasts group out there.

[scottofksu]

Yesterday I was kicking around Facebook Marketplace and found a 65 C60 with what was purported to be a factory installed Detroit Diesel 4-53 engine. I had no idea you could get any 60-66 Chevy Truck with a diesel installed. I would do the 4BT long before I considered a 4-53.

[LS short box]

Because folks that looking at a classic trucks want a GM engine. Not a Dodge 4 cylinder.
Again just my .02. It's your truck so do what you want.

[truckster]

Originally Posted by LS short box

Because folks that looking at a classic trucks want a GM engine. Not a Dodge 4 cylinder.
Again just my .02. It's your truck so do what you want.

Dodge didn't make or use the 4BT. Freightliner used it for some of their box trucks and they were installed in some box vans for companies like FedEx.

Still, I don't see the value of putting a 4BT in a classic Chevy truck unless you're building a truck for the apocalypse and want an engine that can run on alternative fuels.