Crack are what????

[1972ho]

Check this I’m betting it’s a crack 351 cleveland at .030 under on the main after another rod failure right next to it.

[lefty o]

no betting, thats cracked.

[Dan Timberlake]

The ones tiny sharp points originating in the journal fillets/radiuses sure look like the final stages of big trouble.
The the broad buzzy ones just look strange. Kind of like a vibrating engraver's work.

$30 of LPT / dye penetrant chemicals would help decide. Good for extracting confessions from steel AND aluminum and even plastic.

My favorite is wet fluorescent mag particle inspection for steel and iron parts.

[SupStk]

Not looking good. When a crack turns the corner in the radius, its what happens just before you are gifted with a two piece crank.

[dannobee]

...and it's already 0.030" under on the mains? Time for a new one. It's dutifully served its useful life.

Even if it's not cracked, are you going to turn it another ten thou?

[BCjohnny]

Sorry, but I'm going to break ranks ..... at least until there are better pictures

I'm not convinced it's cracking, and here's why

The one main 'crack' line skirts the chamfer on the oil hole, when common sense would suggest it would follow the path of least resistance and run into it, instead it then continues to become a 'lightening fork', or vice-versa .....?

The subsidiary 'lightening fork' branch itself looks like an extension of the line the other side of the oil hole and, if so that one also skirts the oil hole when common sense would also suggest the above

But none of this is easy to see with the flash glare, so put the crank in a well lit area, turn the flash off and post up some more pics ..... until then it's a crap shoot

[lefty o]

Sorry, but I'm going to break ranks ..... at least until there are better pictures

I'm not convinced it's cracking, and here's why

The one main 'crack' line skirts the chamfer on the oil hole, when common sense would suggest it would follow the path of least resistance and run into it, instead it then continues to become a 'lightening fork', or vice-versa .....?

The subsidiary 'lightening fork' branch itself looks like an extension of the line the other side of the oil hole and, if so that one also skirts the oil hole when common sense would also suggest the above

But none of this is easy to see with the flash glare, so put the crank in a well lit area, turn the flash off and post up some more pics ..... until then it's a crap shoot

look closely, the crack runs into the chamfer.

[BCjohnny]

lefty o

I can see where maybe the lesser of all the cracks might run into the oil hole ...... but how do you explain the other major cracks running tangential to it ?

Regardless, and as said, without better pictures, it's all guesswork .......

[Tuner]

It could be that some klutz banged it with the sharp edge of the cap when installing or it fell over against something with a sharp edge. Magnaflux time.

[lefty o]

i dont have to explain any of them. it is very clear that there is a crack into the oil hole as it is visible in the chamfer. the other visible flaws on the bearing surface of that crank could be explained as a number of possible things, but the hair line into the chamfer is a crack. no doubt about it. no guess work, it is cracked.

[BCjohnny]

i dont have to explain any of them. it is very clear that there is a crack into the oil hole as it is visible in the chamfer. the other visible flaws on the bearing surface of that crank could be explained as a number of possible things, but the hair line into the chamfer is a crack. no doubt about it. no guess work, it is cracked.

Ok .... so the smallest 'crack' is a crack, but the more significant ones are 'a number of possible things' ........

Now I get it ......

[Monzsta]

That doesn't look like any crack I've ever seen, and I ran a magnaflux and ground cranks for four years.

[digger]

I'll sit on fence until better pics, the width of marks looks unusual for a crack which should have sharp edges, though the oil chamfer looks plausibly a crack which has implications on other similar marks

[Circlotron]

In the second picture the two parallel lines both have a bright spot at the same end that makes it look like a scratch with the gouged material piled up at the same ends of the trenches. And one of those two lines extends both sides of the oil hole as if something sharp continued across it in a straight line. Not sure about the long mark though.

[modok]

It does not look like a crack IMO
Probably scratches.