[hurryinhoosier62]

Originally Posted by joes455

A good fillet would require it to be at least .040 to .060 tall,that would mean a cut of at least .080 .let me know though about the shim deal.Thanks Tom for your advice

How many cranks have you ground personally? I have ground between 3,500 and 4,000. What Tom is telling you is accurate. With a forged crank it is possible to weld the fillet area and regrind the journal. We did it frequently on cranks we couldn’t find a replacement for. Main journals are actually easier to correct than rod journals since you aren’t having to be concerned about getting a rod journal “on stroke”. It’s your crank; if it were me I’d be having a long discussion with the individual who screwed it up to begin with.

[Jay S]

I assume it is a SGI forged crank, and not a cast. If it was a cast crank I would throw it in with the iron being hauled off.

But if it is a forged, I think even a .010” cut might get enough fillet to look a lot better. Hoosier would certainly know. The 3.25” main is a pretty big diameter to flex and break were the fillet is missing, it should not need a huge fillet. It looked like you have some higher hp build going on, I’d look for a better crank there unless it is fixed. But on something with 500HP or less I’d take your forged SGI crank that is missing that fillet at the thrust bearing over a off shore cast crank.

If it is forged it would be easy for a shop that weld cranks to fix it also. I think you’d end up with the entire crank turned down another .010” from were it is now.

[hurryinhoosier62]

Originally Posted by Jay S

I assume it is a SGI forged crank, and not a cast. If it was a cast crank I would throw it in with the iron being hauled off.

But if it is a forged, I think even a .010” cut might get enough fillet to look a lot better. Hoosier would certainly know. The 3.25” main is a pretty big diameter to flex and break were the fillet is missing, it should not need a huge fillet. It looked like you have some higher hp build going on, I’d look for a better crank there unless it is fixed. But on something with 500HP or less I’d take your forged SGI crank that is missing that fillet at the thrust bearing over a off shore cast crank.

If it is forged it would be easy for a shop that weld cranks to fix it also. I think you’d end up with the entire crank turned down another .010” from were it is now.

Jay, GM cranks are notorious for having incredibly thin radiuses in the the fillets. We modified the radius on our cutting stones to provide a fuller radius without having to grind excessive amounts of material off the journal. If the OP has a radius gauge he needs to measure the depth of the current radius on one of the other fillets. That should give an approximation of how much further undersize the journal will need to be ground to provide an adequate radius. There is a problem with grinding overly generous radiuses in crank journals: the main bearings have to be modified to match.