Cracked block, cast iron.

[flusher]

Nice job. JB Weld epoxy if it leaks a little.
Good luck.

 

[Mark @ Everlast]

It's better to get the leak stopped (if it ever develops) from the inside, than the outside.

 

[Raspy]

So what I have (at least I hope is the extent of the damage) is a block that has 2 cracks each about 3" long between the cylinders in the outside water jacket. Why the freeze plug failed to pop is another issue.

Good job on the repair!

The "freeze plugs" have nothing to do with freezing. They are simply there to plug the holes that were formed by the core during the casting process while pouring the iron into the mold. The holes are where the sand core was supported that formed the water jacket. Once poured, the sand core is broken out, the block cleaned and the holes machined for a plug. Unfortunately, they got named freeze plugs instead of core plugs.

 

[dragoneggs]

It's better to get the leak stopped (if it ever develops) from the inside, than the outside.

Amen on that one! If you can deal with the pressure side... do it.