My T block has never been surfaced, still has original broach marks and numbers stamped in the surface. I have cracks in two exhaust seats that go to the outside part way. The material thickness at the top (all of them) where the port goes through is too thin to pin and install seats. If I did install seats by time they were cut the seats would have to bridge the port where it would be cut away. While there is some erosion from the exhaust, I think the core was too high when this block was pored and by time all the machine work was done things were out of alignment. Even the holes for the gland rings are off center and have a small gap at the top and larger gap at the bottom.
At this point (the block has other cracks in the water jacket) I am going to drill a 1/16 inch hole at the end of the crack and live with it for now.
I am posting this as a heads up. If anyone else has run into this problem and found a way around it that would be of interest.
A better block is my best option at this point, I think.
That would be the only solution, however most all model t blocks will have numerous cracks. The block I took to j an m, which I looked over real good had eight cracks! Even if you cant see them doesnt mean the crack wont grow to become a problem. And sometimes you will be surprised what can actually be repaired!
Mark, I have found the canadian blocks ports are .125 higher in the block than USA blocks is yours canadian?
Lots of blocks have these cracks and I have never seen it amount to anything. Once the crack reaches the edge of the block it can go no further. It would cause more problems repairing them than leaving them alone. A replacement block would be a good thing if there is a lot of core shift but if yours is a rare or otherwise valuable block ignore these cracks and run it.
I would disagree with the statement about most blocks being cracked. I would never consider using a cracked block to start with unless it was real early, say 1915 or 14 and earlier. Even then, I personally would look until I found one with no cracks. Might have to look around a bit good blocks are still plentiful.
Having said that, there may be a point that a cracked block is all that is available, but doubt in my lifetime, and I'm hoping to live a long time yet.
If I was in the business, i would stack the cracked ones somewhere out of the way.