Anyone successfully repaired a cracked engine block?

I rebuilt a 440 a couple of years ago and the builder discovered a crack on the drivers side above the freeze plug. He pinned the crack and didn't seem to be too alarmed. Now fast forward 5 years later I am on the home stretch and breaking in the cam and discovered a small leak coming from the repair. Is this repairable? The engine runs great with this exception...:( Any suggestions?

Get some moroso ceramic seal assuming the crack didn't grow.

Built a 390 Ferd for a local guy last winter.Bored, decked,10.4:1 comp,E-heads,cam,cleaned up, all assembled and ready for break in. Start it up and get steam pouring out of v.c. breathers after it warms up. Shut it down and finally find a crack on the inside of the lifter valley. Installed lacing pins and slathered it in J.B. weld and so far so good. Literally made me sick to my stomach when it started steaming.Those F.E.'s are expensive to build. Same block never leaked before cleaning it out in the tank.Must have broke a scab or two loose.Still gotta install his traction lock to cure his newfound "peg leg tire smokin blues"

I have used this product with very good results. GM uses them for porosity issues.

http://barsproducts.com/catalog/view/6-radiator-stop-leak-tablets-hdc

There were certain years of 5.9 cummins known for cracking... do a search and you'll find lots of info on repairs.

Lock-n-Stitch is the best way I found to repair cracks. Fixed many rare blocks with this product.