I remembered I had this on my computer.

Shows an older GM 6.2 rod, 7.3 Powerstroke rod, and a 5.9 Cummins rod.

That Cummins rod is highly comical in comparison to the others!

Gives ya some perspective...

 

that picture has been floating on the net for YEARS. most think it is of current duramax and 6.0 PS motors but you accurately said it wasnt. the size of the rod means one thing to me in a low rpm motor....weight. higher reciprocating resistence. this is esp true now that the cummins is turning 3K rpms with the 600 based combo. i dont find it to be of any extra value. the load pressures of a 90 degree crank/rod and the fact that only 6 rods take all the pressure as opposed to the 8 in a v8 configuration naturally lends itself to a larger rod. the bearings are the real impressive part in that motor, since it has to take the load of the weight.

but i will say that this is the reason why the 5.9L is a true medium duty motor. combined with a real turbo and a hell of a tranny, it can pull monster loads at part throttle.

 

I've got a piston out of an International rig... the thing is the size of a paint can.

Unfortunately, I don't know what year, size motor, or anything else.

I wish I had a digital camera handy.

 

I've seen this picture a few times. I'd like to see the duramax and the 6.0 ford rods just to compare them.

 

There's really not that much of a difference. They had the Dmax and 6.0 rods next to the Cummins rod at the Houston Livestock show and rodeo. Imagine the other two just a hair larger and you'll get the basic idea. The Cummins is still the biggest. They also had the pistons there as well. Once again, Cummins wins. 400+ from a new Cummins is really easy to do. An exhaust, intake, and a TST box and you've got a ******* wicked combination. I do agree that Dodge needs to step up to the plate with a better tranny. As for the turbo, there's about 30 combinations you can run on them.

 

yeah, because what effing connecting rod is going to stretch at 3000rpm?


You confuse strength with overkill. You also have no idea what the properties are of each metal.

 

Did I say anything about strength and over kill? I just said the Cummins was the biggest. Nothing more, nothing less. When you look at piston speed in the Cummins, consider that it is a 4" bore by 4" stroke (it's slightly bigger but I don't feel like looking at it at this moment). That's a LOT of speed to be slinging those parts around. Those things weigh a bloody ton. The Ford and Chevy's have smaller strokes (or bores, I'm having a brain fart right now). So the piston speed is far less for those engines. There's a reason the Cummins rods are as big as they are. I'm not saying they are the ultimate rod and will never break, I'm just saying that there is a need for a big rod.

 

Why is there the rotated rod cap on that cummins?
The conrods in 1947 Cadillac flatheads that they used in WWII tanks have the same design.

 

It's got something to do with the I-6 design of the Cummins. That's about all I know. Never done much research into the design of it. I just know what it can/can't hold.

 

do the math

one travels 400inch/sec

with a 3.48 stroke (chevy 350)
it is traveling at about 700inch/sec

a 400ciSBC or 383 stroker has a velocity of 750in/sec

(these are averages; max velocity would be a bit trickier to calculate)