Cummins Engine FAQ

[brute4c]

Not: Originally posted by Mcinfantry, Midwest_Welding, & Utahjeeper:

CUMMINS 4BT
pros:
good power
good milage
reuse stock radiator (still cools too MUCH)

cons:
loud
its only 4 cyl
heavy, almost 800lbs dressed out

issues:
tall. w/o a springover/cab lift im not sure how it will fit with the factory "high-steer"
oil pan needs to be notched w/ dana 60/14bolt
you need to fab motor mounts.
2wd nv4500 fits fine, but you need a GM output, NOT a dodge slip yoke

CUMMINS 6BT
pros:
more power
2 more cylinders
you can brag more

cons:
loud
heavy, almost 400lbs heavier than a 4bt
you have to do a springover lift or 3 inch cab lift.

issues:
no intercooler will force you to keep the power output down, or alter the radiator, front valence
do not know if stock radiator will cool it.
the motor is long and expect 4200+ lbs on the front axle, forcing you to upgrade the front.


cummins 4bt specs
cummins 4bt cpl 858 specs
NON intercooled
dry weight 700
hp 105
tq 265
gvw 16000lbs (4x2)
length w/o mech fan 26"
height 32"
width 27"
16cm turbo
the rear sump oil pan starts 10" from rear, and roughly 15" from the front with a height (or hangs down) 5"

the reason the oil pan is included is the height was an issue with front diff clearance. cooling is a non issue on a 4bt. it cools too well with a stock m715 radiator

cummins 6bt specs
cummins 6bt
length w/o mech fan 34"
length with mech fan 38"
height 32"
width 30

my 4bt is bolted to a nv4500. the nv4500 sticks out the stock shifter hole. the 4bt is approximately 3 inches from the back of the radiatior. i have enough room for a 2 speed electric taurus fan, and thats it. there is no possible way to fit a 6bt with a nv4500 coming out the stock shifter hole in the truck and have the stock radiatior where its supposed to be. math shows you would need to move the radiatior forward 4 inches at least, BUT you could move the motor back if you understand the shifter will move back also

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6BT specs:
Here are the basic side to side and front to back measurements. The engine I'm working with is completely stock with the standard 2WD setup. The engine itself is approx 34" long w/o the fan, but with the standard pulley setup. With the stock fan, it's about 38" long to the back of the block. From the back of the block to the c/l of the engine mount is about 18". Side to side, it's approx 30" including the turbo. Without the turbo, it's about 23" wide including the exhaust manifold. The stock tranny is about 27" long.

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For what it's worth, when I built my M-715 (Cummins 6BT, NV-4500, Dodge married 205) I put a 3" body lift on the cab section only. This gave me more room through the trans tunnel to tuck the tranny up above the framerails. It may sound funny, but it looks OK. The bottom of the cab is even with the fording kit storage box on the bed so unless you know 715's it looks like that is the way it is supposed to be. I did have to cut out a section of the bottom of the fording kit storage box and weld in a filler piece to make room for the rear driveshaft. I just made a semi circular notch through it.