6.4 broken crank

Wayne · Jun 16, 2015

Just curious to know if anybody else has seen, or heard of one breaking. The long block is stock except for head studs. It's got nearly 200K on it with a built trans, twin pumps, 50% over injectors, and billet 75/59 stock appearing turbos, an a conservatively adjusted gate since it still has stock valve springs for reference. When I got it, it was still running, sounding like it was gonna split in half with the banging, and it did have a bunch of blow-by. Should be fun to see what other carnage I might find when I finish the tear-down.

madman1234509 · Jun 16, 2015

I've seen one other mention of it on here, and another on fb. I want to say neither truck was a crazy build or anything. Both of those were within the last 8-12 months.

sootie · Jun 16, 2015

if im not mistaken, Dustin had one like this also?

webb06 · Jun 16, 2015

Ya Dustin had one sometime last year. I've seen a 6.0 with a broken crank a couple times

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Wayne · Jun 16, 2015

huh. well, there ya go. I didn't realize is was common as it is. Thanks guys. are these on close to stock trucks?

powerstrokedkid87 · Jun 16, 2015

saw one on a tuned and deleted 6.4 a while back, also saw the ones mentioned above...I know the tuned and deleted one was beat to H*** back

qcfarmer · Jun 16, 2015

Dzchey21 · Jun 16, 2015

I had one that broke in the same exact spot wayne Bone stock truck with 160K on it

Dzchey21 · Jun 16, 2015

also the only other thing wrong with the engine was it spun a center main bearing and was going to need line bored. The cylinders and everything else looked fine. I drove it on the trailer, but it sounded terrible. When I tore it down I couldn't find anything wrong. Then I thought I messed up and didn't check the flex plate or something good enough. I was then checking thrusts and found that the crank was broken, From what I asked around not too many other people had seen it. I sent it to the failure analysis guys up at our bigger branch, they were blaming and overfueled single cylinder but the truck history didn't have anything on injectors or anything like that and I reassembled the truck with the same fuel system and deleted the dpf and its been going strong for the last 20k so I don't think that was it.

I think its a machining flaw from the get go, this one had been breaking for a long long time.

If you can when you get the crank out take a really close picture at the break so I can look at it please.

Wayne · Jun 16, 2015

you bet. I'll try to use my potato 2.0 camera. It'll be in the next couple days. In need to get that block to the machine shop by the weekend... or maybe another block :fustrate: