Crank problems/repair?

[dank GN]

How’s it going all ? I have 3 nice cranks and one of them has a cracked thin piece of metal . Is there a reason they left this thin pieces in between the rod journals? Is there a way to fix this ? Do I have to send it to the scrap pile ?

 

[750H.P.V6]

Chris,

The fillet piece you're refering to is used to maintain rod side clearance and factors into oil control to that rod journal. The damage appears mostly cosmetic. You should have the crank magged to make sure it doesn't have any cracks.

Neal

 

[dank GN]

Chris,

The fillet piece you're refering to is used to maintain rod side clearance and factors into oil control to that rod journal. The damage appears mostly cosmetic. You should have the crank magged to make sure it doesn't have any cracks.

Neal

How can you say it’s cosmetic there is a flap hanging off . Should I just cut it off ??

 

[750H.P.V6]

There isn't a good way to fix it otherwise. I'd mag the crank and make sure it doesn't have any other issues before attempting to rework the damaged area. You can get a 2nd opinion from your crankshaft guy too.

Neal

 

[ek02]

I bought a 3.8 that had that area repaired on the stock crank, but whoever did it never ground down the welds properly and it ate up the side of the rod which caused an odd tapping noise under acceleration. A good crank shop could probably Tig weld it and grind it properly.

 

[dank GN]

I bought a 3.8 that had that area repaired on the stock crank, but whoever did it never ground down the welds properly and it ate up the side of the rod which caused an odd tapping noise under acceleration. A good crank shop could probably Tig weld it and grind it properly.

What I’m most likely going to do is Tig weld it back then grind down the weld . Then take it to a crank shop and have them check it out for cracks and fatigue.

 

[750H.P.V6]

Chris,

Don't start welding on the crank without getting the input of a qualified crankshaft shop. I've got a guy down here in my area I have been dealing with for about 25 years that can give you an honest opinion but based on where you're located I'd suggest you take it to Castillo's and see what they say.

Neal

 

[rag231]

The only welding that I have had done to a crank has been under water. I have a BMS crank in service that has has a fillet ground down from the way it was machined. It is a crank that doesn’t have rolled fillets like the stock crank. So far it hasn’t shown any adverse signs, 9+ years strong. I sent it off to one of the best crank shops in my area . It was magged and they said it would not be beneficial on that particular crank. It was a raw forging to begin with and I guess they got the width between that journal a little thin, nearly identical to yours. Before you weld it and create a potential short block issue , I would send it off to the best crank shop ( if they are familiar with Buick V6 cranks , even better) and get an opinion on it. You could make it brittle in that spot and harmonics would scatter it at high rpms. I have seen this only on cast cranks never on billets. I knew a guy so deep into cranks that he would check its resonance frequency with a tuning fork.