Depending on where the crack is, and how deep a particular stovebolter's pocket happens to be, some head cracks can be repaired. There are a number of methods of fixing a crack, some more expensive and/or effective than others. One of my favorites involves "sewing' a crack with a series of overlapping threaded tapered plugs made of similar cast iron material as the head. The fix involves finding both ends of a crack, "stop-drilling" it to prevent it from spreading, and drilling, reaming and tapping a series of tapered holes which are then plugged one at a time with cast iron inserts, The insert is cut off flush with the head surface, the next hole is drilled and tapped to overlap the previous one- - - -etc. until the crack is eliminated. The downside is the setup cost for a machine shop to equip itself to do the work- - - -several hundred dollars' worth of tooling, and plugs sold in minimum quantities of 100.
Welding is another option, with its own set of difficulties- - - -mostly preheating, post-heating, peening, slow cool-down and expensive special nickel-alloy welding rods.
Wait a few minutes, and some Google Guru will be along with a page full of research to "prove" I don't know what I'm talking about!
Jerry
