How much heat in this bearing?

[20psiofevil]

Friend snaped a crank ( similar crank I'm running) and I'm trying to investigate for my own piece of mind. This looks clearly to me like a oiling issues or bad line bore job. Any opinions welcome.

 

[bison]

Hard to tell what happened first


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[20psiofevil]

Hard to tell what happened first


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From what I gather it went like this... the car was at high 5000rpm, big bang and the engine was done because it took out an exhaust valve and damaged 2 rods and pistons. I question the heat lines on the bearing as being the cause of failure. but I'm no expert.

 

[750H.P.V6]

It looks like the crank had been running for a while with a crack that started in the rod radius of the #6 journal and finally let go.

Neal

 

[20psiofevil]

Casting defect perhaps? This was an oe 3.74" stroke ford crank. I'm running a scat 9000 in mine that was made in china probably lol. This engine was making around 600 hp to the tire but people have gone a lot higher than that. A reputable engine builder brought up flex so this is also a real good possibility. Another detail I left out is this engine turned 7000rpm and run 373 gears. There is a video of it running bouncing off the factory rev limiter (fuel cut) about the last 300' and he stayed in it for a few seconds at 7000rpm. to me this could be another cause. Shocking the rotating assembly at this high rpm causing deflection to the crank. If I find the video I'll post it.

 

[20psiofevil]

Would this cause a crank to break? Riding the rev limiter like this? fuel cut limiter btw...

 

[bison]

Hitting a rev limiter is never a good thing. Wrist pin damage is common


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[750H.P.V6]

The crank appears to be cast and isn't designed for the H.P. level it was being used at. Based on the split crankpin design which is similar to an even fire Buick V6 the weak point in the crankshaft design is between the # 5 and 6 rod journals. Due to the 3.74" stroke length the crank is inherently weaker then a stock stroke crank. What application is this crank from?

Neal

 

[thadeal4real]

number two main looks pretty bad and what does the oil pump look like

 

[20psiofevil]

The crank appears to be cast and isn't designed for the H.P. level it was being used at. Based on the split crankpin design which is similar to an even fire Buick V6 the weak point in the crankshaft design is between the # 5 and 6 rod journals. Due to the 3.74" stroke length the crank is inherently weaker then a stock stroke crank. What application is this crank from?

Neal

https://en.wikipedia.org/wiki/Ford_Essex_V6_engine_(Canadian)
This is the 2nd high hp crank I've seen that has cracked. Both were ford oe crankshafts made in mexico. The new cranks are made in china. Not sure if the metallurgy is different but there are a few in the 700rwhp range with the china and 1 I know of in the 800rwhp. I was actually told by my engine builder that 700rwhp is the limit. I have the beefy caps on mine and a girdle. I would estimate my power in the 580range (you se my concern lol).

 

[BOP4ever]

Sure looks like a fatigue crack that propagated to final failure.
Would need a better picture of the fracture face to say more.
It didn't happen all at once.

 

[TurboBuRick]

No bluing. Why would you think it got hot?

IMO Had to be something already wrong with the crank.