It's Official I have a Broken Crank

[wdino73]

Ok guys, I tore my engine down this morning, I took pics but haven't had time to load them, My crank is broken at the first counterweight, No other damage is done which is a load off my mind, I guess the positive of the negative is that I just need a new crank and bottom end bearings. I'll try my best to get the pics up as soon as possible and maybe you guys who have seen this before will give me some of your knowledge and help me figure out what happen and what we can do to make sure this don't happen again, for me and the Duramax Nation. I really appreciate all the support I've received so far, Thanks Guys :thumb::thumb::thumb::thumb:

 

[McRat]

Look for signs of heat. Purple bearing, glazed oil, etc.

 

[fishsmith]

That is the same place mine is broke

 

[McRat]

All the broke ones I've seen but one were broke up front as well. We have not broke a crank yet, but I've seen a half dozen (mostly LB7) in the area.

 

[wdino73]

I didn't see any scoring or color change on the journals, I'm incline to believe that the shear inertia of the 25 lb. fluidampr had a big part in the break, if the crank was broken in another spot I would believe injector, or torque convertor could be to blame, how do you guys feel about that scenario???

 

[x MadMAX DIESEL]

Letting off the throttle quick surely would not have been good. Did you ever get off of it real hard? enough to let make the turbo bark.

 

[NJ_LLY]

Are you serious? Iv had my turbo bark about 30 times and no broken crank. I think we all know why the crank broke.

 

[x MadMAX DIESEL]

Are you serious? Iv had my turbo bark about 30 times and no broken crank. I think we all know why the crank broke.

I'm talking about with a brand new engine not broke in yet.. Getting off the throttle (just said enough to bark to show how quickly you let off it) I think it's possible that everything rotating in the engine wants to stop moving emediately being its so new. while the balancer is just wanting to still spin full speed. I may be wayyyyyyy off, so be it. That's just my guess, nothing more nothing else


Why did the crank break? sense everybody else but me knows

 

[TheBac]

Sorry to hear, dino. Were you able to find another one?

 

[bfletcher]

Fluidampr....

 

[JoshH]

Why did the crank break? sense everybody else but me knows

I'd like to know too. You aren't the only one out in the cold on this one.

 

[Bako_Dmax]

So why did the crank break?

 

[TrentNell]

If it wasnt for the other broken cranks we have seen my guess would be the use of studs and no line hone on this motor , but the bearings would have tall tell signs if that were the case so probably not . I sure wish we knew but it seems as though it could just be casting flaws or something of that nature , All i know is, it sure is confusing, and seems odd to me that more built /rebuilt motors seem to be breaking them than stockers ( and not all big power trucks ) , leads me to think it is an assembly issue but there hasnt been any signs from anyone who has inspected them after the tear downs unless they have held back on info .

 

[Kat]

Fluidampr....

What about the stock engines that are breaking cranks in the same place?

 

[wdino73]

I bought a new one from GM, I was told by a Tech,, that the replacement cranks were strong than the original, ( If that's true or not I don't know ). I was extremely particular with the brake ins to much money invested don't to be, but I appreciate all the comments, the bearings looked very, good my machine shop said they looked good enough to re-use, but I'm going to buy new ones anyway. Oh, and like Trent said after tear=down some people may not give the true findings because it may have been their fault and I agree with you Trent. but I promise I will disclose all the info I find but it hurts me deeply when I hear of one of our engines going down after something like this, I'm proud to own a Duramax and want my to run as best as I possible can afford it to, and I know first hand the work it takes to pull the engine and build one and the time and money to do it right, kudos to all that undertake to build up one of these engines that don't have sponsors and use their own money........

 

[JoshH]

What about the stock engines that are breaking cranks in the same place?

Or built engines with stock balancers? Does anyone know of a SoCal/ATI Super Damper equipped engine that has broken a crank? Did 1badmax have a SoCal Damper? What about Rhall, didn't he recently break a crank?

 

[wdino73]

Now thst's a good one Josh and an interesting,Oh and I know from reading other thread how some people can get carried away so I don't want this thread to turn in to a bash, I started this for the education and social use nothing else so please for future reply's lets keep it professional like it is right now, please:thumb:

 

[wdino73]

Pics enternals

Here's the pics men, the bearings are layed out left to right,, odd on top even on bottom

 

[SIKDMAX]

I know that feeling

 

[wdino73]

LOL, I thought alittle humor in the face of woe was in neat,