New crank cracked counterweight

[turbovan]

Started measuring bearing clearances for engine assembly and I noticed a crack in my brand new Scat forged crank. Looks that it was caused by the machine shop during balancing and I’d appreciate some opinions on what to do. The hole drilled for balancing seems too close to the edge leaving only a very thin 0.045” piece of the crank in that area which is where it’s cracked through, and even pushed out by the drill bit.

Hard to tell from the pictures, but that line at the bottom is cracked through, and there is lite splintering/star pattern cracking above that line.

Do I need to worry about these cracks spreading? It looks like the beginnings of a worse problem, and this is a turbo build which will see every bit of 800+ Hp.

 

[360duster]

to be honest, the welding inside of the hole does not look professionally done to me....i´d worry about this coming loose, too. I would not trust this crank.

Michael

 

[ch1ll]

I’m not seeing any cracks, but I see break through from the drill. You would have to check it with dye and developer used to find cracks in steel. By the heat coloring on the metal from drilling, that area got over 600F. Poor job of drilling off center not using enough coolant or cutting fluid. Definitely not done by skilled labor and whom ever did the job owes you a new crank.

 

[mcodecuda]

Why don’t you just contact SCAT?

 

[Rat Bastid]

Send it. They just have the balance hole a bit off center. It won’t hurt a thing.

 

[turbovan]

I’m not seeing any cracks, but I see break through from the drill. You would have to check it with dye and developer used to find cracks in steel. By the heat coloring on the metal from drilling, that area got over 600F. Poor job of drilling off center not using enough coolant or cutting fluid. Definitely not done by skilled labor and whom ever did the job owes you a new crank.

Yes, break through; that’s the right word for the line I circled. There are tiny cracks above that though that I can’t get on camera. The heat is from welding inside/between the two holes. Not from the drill bit if that matters.

 

[turbovan]

Send it. They just have the balance hole a bit off center. It won’t hurt a thing.

This is what I was thinking, but the splintering cracks(that won’t show up on camera) are what worry me. Taking it back to the machine shop this morning to get their opinion, and hoping it will be an honest one.

 

[justinp61]

I wouldn't have any problems running it, but I would talk to the machine shop that did the work to see what direction they would take if it caused any problems down the road. Get anything in writing, dated and signed too.

 

[jos51700]

Uh, what the hell were they welding down in there?
Harmonics are a ***** and if that counterweight were to lose integrity at high-RPM, it's liable to compromise the integrity of your oil pan and rear tires.
There's other, far better, ways to take weight off a crankshaft, and the piss-poor machining on that one makes me think Yang-Li doesn't really give a crap.

I wouldn't run that thing in my lawnmower.

 

[Bobzilla]

Started measuring bearing clearances for engine assembly and I noticed a crack in my brand new Scat forged crank. Looks that it was caused by the machine shop during balancing and I’d appreciate some opinions on what to do. The hole drilled for balancing seems too close to the edge leaving only a very thin 0.045” piece of the crank in that area which is where it’s cracked through, and even pushed out by the drill bit.


View attachment 1715990662

View attachment 1715990663

View attachment 1715990664

View attachment 1715990665
Hard to tell from the pictures, but that line at the bottom is cracked through, and there is lite splintering/star pattern cracking above that line.

Do I need to worry about these cracks spreading? It looks like the beginnings of a worse problem, and this is a turbo build which will see every bit of 800+ Hp.

Please try to post up-close and clear pictures of the welds inside the holes.

What is the stroke of this crank, and what is the bob weights used for this balance job? I am wondering why they drilled so many damn holes to begin with.

 

[512Stroker]

Started measuring bearing clearances for engine assembly and I noticed a crack in my brand new Scat forged crank. Looks that it was caused by the machine shop during balancing and I’d appreciate some opinions on what to do. The hole drilled for balancing seems too close to the edge leaving only a very thin 0.045” piece of the crank in that area which is where it’s cracked through, and even pushed out by the drill bit.


View attachment 1715990662

View attachment 1715990663

View attachment 1715990664

View attachment 1715990665
Hard to tell from the pictures, but that line at the bottom is cracked through, and there is lite splintering/star pattern cracking above that line.

Do I need to worry about these cracks spreading? It looks like the beginnings of a worse problem, and this is a turbo build which will see every bit of 800+ Hp.

Man thats alot of weight they removed, looks sketchy, I would be wondering if it is truely balanced?
That crank would not go in my engine. That's just me
Good luck keep us informed

 

[Rat Bastid]

Uh, what the hell were they welding down in there?
Harmonics are a ***** and if that counterweight were to lose integrity at high-RPM, it's liable to compromise the integrity of your oil pan and rear tires.
There's other, far better, ways to take weight off a crankshaft, and the piss-poor machining on that one makes me think Yang-Li doesn't really give a crap.

I wouldn't run that thing in my lawnmower.

Do you know how many cranks have some weld in a hole that needed weight? I say a million and that’s pro low by an order of magnitud.

Theres nothing wrong with it.

 

[jos51700]

Do you know how many cranks have some weld in a hole that needed weight? I say a million and that’s pro low by an order of magnitud.

Theres nothing wrong with it.

I don't disagree but do to so after going nuts drilling holes is the issue.

 

[turbovan]

They didn’t add much material in those two holes. Bob weight is 1955.
Machine shop says the crank will be fine…after first denying that they drilled that hole and stating the factory drilled it. So I’ll hope for the best.

 

[RAMM]

It's not ideal but the crank will be fine. Heck I just put together a circle track SBC 358 with some old crank that probably had at least 4 balance jobs judging from the amount of drillholes and welds and Mallory--Here's the thing--When I went to put it back into the engine I could hear a light clinking noise when I would rock the crank in my hands. Best I can figure is some loose metal is trapped under one of the many plug welds. Made 580+hp on the second pull and has a feature win already. "Shrugs shoulders" J.Rob

 

[Max1196]

Think yourself lucky a **** show like this wasn't cobbled together. Oh wait, where'd that other one go.

 

[Rat Bastid]

I don't disagree but do to so after going nuts drilling holes is the issue.

Have you ever balanced a crank? Factory holes can be off. And they are. Guys who don’t know make mountains of nothing. It’s NOTHING.

 

[Bewy]

I would be more worried about that daggy lump of weld coming loose at high rpm......

 

[jos51700]

Have you ever balanced a crank? Factory holes can be off. And they are. Guys who don’t know make mountains of nothing. It’s NOTHING.

Then buy it from the guy at a steep discount, jam it in YOUR motor on YOUR dime, spin it to the moon, and be content.

It's not the balancing that concerns me. It's the piss poor machining, potentially weak welds, and the fact that crank harmonics are a thing. I'm not even sure that those two holes don't intersect at the bottom.
I've never balanced a crank but I've handled a billion that didn't have half assed crap like that done to them, and I've yet to see a 100,000 mile crank that DID have that kinda crap done to it on day one.
Sorry, but if Ying Chao can't be troubled to center up the drill bit in center of the counter weight, I ain't gonna trust anything else he's doing, either. That's me, and my policy. If you disagree, that's fine. Spend YOUR money on it.

 

[Rat Bastid]

Then buy it from the guy at a steep discount, jam it in YOUR motor on YOUR dime, spin it to the moon, and be content.

It's not the balancing that concerns me. It's the piss poor machining, potentially weak welds, and the fact that crank harmonics are a thing. I'm not even sure that those two holes don't intersect at the bottom.
I've never balanced a crank but I've handled a billion that didn't have half assed crap like that done to them, and I've yet to see a 100,000 mile crank that DID have that kinda crap done to it on day one.
Sorry, but if Ying Chao can't be troubled to center up the drill bit in center of the counter weight, I ain't gonna trust anything else he's doing, either. That's me, and my policy. If you disagree, that's fine. Spend YOUR money on it.

I’d suggest you balance several hundred cranks, preferably some of the cranks will have been balanced by someone else and some will have bobweight changes and then you can criticize how someone gets it done.

And dont forget, you have to make money and keep the doors open, pay taxes and labor and all the rest.

Ive said it a million times. If you have to fix something someone else has worked on, the labor rate should be 10 TIMES higher than standard.

 

[MOPAROFFICIAL]

Uh, what the hell were they welding down in there?
Harmonics are a ***** and if that counterweight were to lose integrity at high-RPM, it's liable to compromise the integrity of your oil pan and rear tires.
There's other, far better, ways to take weight off a crankshaft, and the piss-poor machining on that one makes me think Yang-Li doesn't really give a crap.

I wouldn't run that thing in my lawnmower.

Yep. Grinding/knife edging.
No booger welding allowed.
That's a piss poor job.

 

[jos51700]

Yep. Grinding/knife edging.
No booger welding allowed.
That's a piss poor job.

This.
If it was stocker crank I'd be less critical of it.
But it's not. Regardless, I hope it works out for OP, whatever path he chooses.

 

[A56]

They didn’t add much material in those two holes. Bob weight is 1955.
Machine shop says the crank will be fine…after first denying that they drilled that hole and stating the factory drilled it. So I’ll hope for the best.

View attachment 1715990943

"Machine shop says the crank will be fine…after first denying that they drilled that hole and stating the factory drilled it.''
^^^^^^^^^^^^^^^

I'm no expert but that right there would always be in my head...............