OEM specs, with better steel.
Few OEM cranks break first year, so guessing only time or mileage will tell that tale.
Few OEM cranks break first year, so guessing only time or mileage will tell that tale.
Broken Crankshaft Count?
- Thread starter EDP
- Start date
Got real lucky, really.Built engine lbz race truck I'm tearing into.
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The pics ikeg posted happens to be my truck... my buddy put a go pro in my truck thst night. I have a good video of it breaking just don’t know how to post it.
Tore my engine down cause of a crack in cylinder 7. Ended up finding this. Was a new LB7 crank that was externally balanced. AF cam since it was new. Engine had 3 hard seasons on it. First year around 800hp. Second year around 1100hp. This year 1300+. Track numbers not dyno. This forum wont let me post pictures but was where they normally crack.
Guess you can add another broken crank to the list ? is this a duromax issue that is being kept secret? Mine is a completely stock 2015 with 200,010 miles on it. Might seem a lot but to me that was pretty low miles. I have had both Ford and dodge and had to put trannys in at around 250k, but a motor ! Something seems rong here. GMC said 16-18k to fix it. I guess now I make payments on a dead weight !
There are much better and certainly cheaper options to repair it.
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Yeah like some legal firm filing a class action about it..
I got $200 from Ford for my 6.0L junk EGR cooler several years after warranty was up. Back in the 90's GM paid to repaint couple silver cars I owned also...
It seriously should be addressed, like the CP4 fiasko at minimum.
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Gale Banks says his fluid damper will prevent this and has a YouTube video on it. I think it is a design flaw that only a redesigned crank will fix.
Exactly, we have seen a ton of them broken with Fluidampners also. It is a design issue plan and simple. Block really needed to be 2" longer so the crank could have thicker throws. Marketing at it's finest...
I think the biggest point made by Gale in his video wasn't necessarily the fluid damper but internally balancing and not swinging a huge weight outside the mains.
I can only say the neutral balanced, AF Cam, and Fluidamper combo is one of the smoothest spinning V8 assemblies I've ever laid hands on. Betting others will agree. With an 80lb flywheel on em, I've yet to feel that RPM harmonics shake that's common on stock units. So something to be learned there I believe.
Wonder why they dont make a viscous filled 80 lb flywheel to help with the bal , never mind I just figured it out myself , because every time you would start the eng the viscous material would have to rebalance , thus damaging the eng bearings a little on each startup .
A viscous flywheel wouldn't help. The problem is the counterweight on the damper when the distance between it and the front main on a Duramax is so far. Think about it we are swinging a large weight at the end of a long lever. The counter weight on the balancer puts an extreme load at the common breaking point. If you move that weight to between the mains where it is supported at each end you eliminate huge amount of that stress from the crank. I think a combination of internal balance and an altered firing order cam along with a good damper viscous or not will solve all the problem
I like the principle of more internal balance , it would be nice to see how many cranks with internal balance broke also . I also think Mark is spot on also . All we can do is keep hoping for a solution . I was thinking of when I first started racing 1968 building 283s very small dampers then the high revving lt1 350 with a giant damper that looked 3 times the size of a 283 , I never broke a crank in any of them even when I switched to big blocks I loved my 427s bored out to 452 thats 125 over. Maybe lp5 will save us .
It’s been tried many times. They still break internally balanced with a alt cam.
I would be willing to bet that most every broken crank that was internally balanced wa well in excess of 1000 hp and broke farther to the rear.
Every thing has its limits, how many examples here have been internal balance shafts?
I am currently not disputing you Even in fact I have the utmost respect for your experience, knowledge and contributions to this community. Here I believe we may be moving beyond one issue and in to another and I certainly hop I am not wrong and I am tying up a lot of money in a build banking on it
Every thing has its limits, how many examples here have been internal balance shafts?
I am currently not disputing you Even in fact I have the utmost respect for your experience, knowledge and contributions to this community. Here I believe we may be moving beyond one issue and in to another and I certainly hop I am not wrong and I am tying up a lot of money in a build banking on it