I'll get pics on here of mine soon but I had my lbz one break at the 4th journal have no idea why but I have it sitting out on the garage floor right now
Broken Crankshaft Count?
- Thread starter EDP
- Start date
here's the crank
Mine looks identical.
125 000 miles, stock engine, mild power. Cruising down the highway when it let go.
Improperly installed converter is my guess- 2 bolts finger tight, two moderately tight, two tight but not to spec. unevenly loaded it and stress cracked over time.
You had the ats 5 star too right? Some people say the 5 stars are rattle traps which may have contributed to the breakage we have all my bolts were tight but I dont wanna risk the chance with my new motor when it's done so I'm getting rid of the converter
By looking at your 2nd and 4th cap-side bearing shell you notice similar level of wear, look at the top-side main for 3. Majority of flex is within these 3 main journals. Now figuring why viewing from each of end of the crankshift, which has been in discussion multiple times, why, from seeing your pictures the crank is acting in the sense of a jump rope.
When looking over bearings as well you must look at all points across the plane because the flexibility as well as machine work (of the journal in this conversation) and bearing crush/fit will imprint into the bearing, you just have to decipher whats happening during operation. Remember just because an engine may be a factory built piece in your or anyones truck. the machine work tolerance isn't as tight as your race mill. The tighter your tolerances the longer your combination produces and stays together on any machined surface.
Things don't fail until something makes it fail.
Perhaps the shape and mass distribution of the counterweight can be in the equation for the failure as well??
I broke the crank in my lly 2.6 pulling truck the end of my 2012 season. It was a stock lly crank that had been made a stroker. It broke right in front of the first rod. ATI balancer, ATS flywheel, Girdle, Billet Mains, ARP studs, Partial filled block and full built motor. It broke right at the end of my pull and didn't hurt anything else. I got a billet Crower stroker crank made for the 2013 season and upon inspection yesterday it's cracked after 22 hooks. This one is cracked right where the 2nd rod meets the counterweight.
That's expensive, you should post that in the fingers section in the thread named "cranks" did you have a stock firing order cam or alternate?
Sent from a truck somewhere in the US
Sent from a truck somewhere in the US
I have a stock firing order cam and yes this is getting very expensive. I need to try and figure something out because with the price of parts I don't wanna be putting a new crank in every year.
Alt. fire cam shaft seems to be the answer for now... I know Fingers is working on a crank simulator to test the cam & balancer theories. Alt. cam is the only fix that hasn't been dis-proven yet...
Is there any company currently building cams for the different firing order or are you guys just getting a company to make them when you need them?
NGM Diesel have them as well. It probably has a lot to do with the rpms that you turn pulling combined with the overall dynamics of Tue rotating assembly.
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