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Roland..... ..yes, I think a better option would be "stitching" your crack with overlaping drilled and tapped screws the length of your crack. You can do "stitching with handtools". In welding castiron, ya gotta do alotta heat control to prevent re-cracking the castiron. And always drill stop hole at end of crack. While "braze" is also a castiron "fix", dunnno if'n you can gettitt clean enuff and fluxxed enuff. Bottom line is yer probably gonna haffta split yer tractor so you can at least get to the crack for whatever repair procedure you choose to pursue..... ...Dell, who doesn't know diddly about welding Heres some notes I've coppied over the years about welding CastIron.
Over the years there have been many threads here on the N-Board about repairing, by welding, of cast iron. Contrary to most peoples belief, ci CAN be welded, AND can even be welded COLD - that is without "preheating" and the requisite slow cooling - when done PROPERLY!
The key to welding is to find some that has done it many times before. Ask around, I'll bet you can find an "old timer" that "knows his stuff" and can weld it almost as good as new. You will want to ask to "see" jobs that he has done, so ask who he has done ci welding for and how to contact them to check on his success.
Strange you should post about a cracked block, since just earlier I posted about welding, etc. suggesting people might get the Forney Welding Manual as a good reference manual to have. Since it is still here next to the computer I'll quote what it says about CI welding.
"The rule of 'weld little and cool much' is a good one to follow. Beads should not be longer than ½ to 1 inch long at a time. Peening of the bead with a small ball-peen hammer of chipping hammer will help to relieve the stresses and strains created by the heating and cooling of the metal. When the bead is cool enough to touch momentarily with the bare hand, the second bead of the same length can be run." Note: the peening must start immediately after the bead is run, while it is still hot - per elsewhere in the book. I've forgot my metallurgy, but as I remember, it has something to do with the crystal growth in the weld and surrounding area - rest is "lost in space", you know that empty space between the ears. :-) The book also shows the sequence for welding a crack in a block. The first bead is at the "end" of the crack. The next at the opposite end, or at the end of a second crack, etc. such that you place the beads as far apart as you can so each successive weld heats a new area not one that is already hot. After all the ends, a bead in the middle would be next, then next to each bead at the ends, in same sequence as you started, then back to the middle or middles, alternate sides of the middle, etc. They also say NEVER to get the casting so hot that you cannot touch it lightly with your bare hand. This is more time consuming than I would expect professional welders would or could take, but maybe I'm wrong. I'd "quiz" any welder I was to do the welding as to how he would do it. Welders have the skill to weld but not always the full knowledge of the welding process. Having the Forney Welding Manual in you hand when you are asking would be a good idea, since some guys can be touchy about their work. :-)
Cast iron will obey the laws of physics, even if you don't know them.
Temperature controls the outcome.
Let's add together the things you have learned about expansion and contraction along with temperature control and review the ways to prevent stress from building up in your welded cast iron parts:
Use a high temperature preheat when welding in the center of a casting.
Limit low temperature welding and brazing to corners, ears and ends.
Use a proper preheat and maintain the part at the appropriate temperature during the entire welding process.
Cool the casting very slowly in order to allow the weld affected area to stretch with the contraction of the weld.
Metal stitching avoids all of these problems. And it can be used on approximately 90% of all repairs of cracked castings. See: www.locknstich.com
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