Cracked crankshaft

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and..
what would happen if it let go just as you hit 6000 rpm in third passing a long line of cars, fully loaded Semi coming at you??

Glen

Glen, for the benefit of the English speakers amongst us, what is a ‘fully loaded Semi’...?
 
If you’re not gonna use the crank it would be very interesting to cut through it and see what the crack looks like inside the metal.

Based on the replies I'm not sure there would be the interest to warrant the time or cost. I have the replacement crankshaft and will rebuild the other as time and a replacement cheek comes available.
 
Think articulated lorry...with a full load...on a B road in a corner...and he is over the line.
 
And his grandpa was driving it. He used to be his grandma before she grew a pair.:rolleyes:

Now I gotta wonder how many more ticking time bombs there are out there, running merrily along, just waiting for the rider to make a pass. I, for one, won't be tearing mine down to look.
 
My point is that I wouldn't put a known fault of that type back in the engine. I do get into the exact scenario mentioned above quite often. The oncoming fully laden lorry or fully loaded Semi scenario was for dramatic effect, hitting any kind of auto head on will produce the same result.


Glen
 
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My point is that I wouldn't put a known fault of that type back in the engine. I do get into the exact scenario mentioned above quite often. The oncoming fully laden lorry or fully loaded Semi scenario was for dramatic effect, hitting any kind of auto head on will produce the same result.


Glen
Of course you wouldn't. Neither would anyone else in their right mind. I guess I'd just like to see the resulting carnage if that longitudinal crack let go, if it's happened. Plenty of pics of rod failures, holed pistons, dropped valves, cracked cases yadda yadda yadda, but the Norton Twin crank has always seemed the most robust of it's components, rarely failing when normal bhp figures are put through it. And I wonder what the first guy to see the "taint crack" thought?
 
It seems a crack on that D/S journal is not new, there was a MkIII crankshaft with a similar crack posted on facebook which even had a link to this thread. Others posted of cracking also.

Further to posting #4, if you are close to an engineering college or a university, maybe they will examine the shaft for free? It is certainly an interesting study object.

-Knut
 
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