DCTOM and Don L and all

Now for the real stuff. About 8 years ago, I started tearing down my first tractor (1941 SC) which was left to me by my grandpa. You may be able to view my pictures in the website still. Anyways.. Took me about 5 years to complete-being that I was 12, I had to cut a lot of lawns to pay for parts. It took a while. So after new rings, a boiled 5618 (shaved) head, rebuilt magneto/generator/starter, carb kit, resurfaced valves, new engine gaskets. It ran pretty good for the first couple years-02 thru 04. From 2004 to summer of 2006 it sat in storage-not the best-but we sold the lake home, and I had no other place to put it. Figured I would get it out and do some tuning up. New coolant. No leaks there. Good. Drain the oil. COOLANT IN THE OIL! posted a forum, and was told it is probably a bad O-ring on #4 cylinder. So a $4.50 O-ring is going to take me to a complete engine teardown. Wondering if I should just tear it all the way down. I eventually want to go through the whole tractor, and at this point in my life (20 years old) I figured I may as well start it now, and if I don't have it back togeather for two years, then so be it. I know it needs brake seals. Water pump should be gone through. I also would like to see about getting the block welded behind the carb. At one time I believe it may have thrown a rod (one because there are 3 5/8" oversized pistons in it, and two because of the patch behind the carb) The patch is about 6-7" long and 2" high directly behind the carb. I have taken the patch off that was on there, and there is no hole, it is almost like there is jbweld smeared into where there was a hole. The problem is, with the patch, there are about 20-30 small bolts tapped into the block securing the patch on-not to mention some RTV gasket maker to prevent any leaking courtesy of myself- How in the world would I go about repairing this patch without spending a fortune?!?! I know it costs quite a bit to weld cast iron, from what I have been told $100.00-$250.00 per inch! It is the original block, so I would hate to mismatch numbers, but if that is what it would take to get it running right, then I will have to do it. But it has ran fine the past 20, 30, 40, 50 years with this patch. One last thing. It had a Marvel Schebeler carb on it when I started the project, and originally got it running. Just this past summer I replaced it with the original Zenith. Adjusted as per the repair manual, fine tuned, and checked the flow of fuel and air. Still wouldn't run without having the choke on. It would actually backfire into the carb and I would get this faint popping sound. Any ideas? Sorry to rant, but it has been QUITE a while. Good talk!

If the crack is truly a freeze crack, there is another method that engine rebuilders (especially large diesel truck engines) used called lacing. You can buy lacing kits. It consists of a special drill bit, tap and threaded cast iron plug sections. Start drilling about half a hole past the end of the crack and drill in, not all the way through, then tap the hole. The tap is a tappered tap like an NPT pipe thread. The threaded rod is then screwed in until it breaks off in the hole. Then the process is repeated. Starting by drilling in with about half a plug overlap, tapping and screwing the plug in, etc. until the complete crack has been done like this.