I've heard of this procedure but never saw it done. I'm sure some of you old timers have seen it or have even done it yourself.

I think this is a very interesting video. I watched both all of the way through.

 

Great instructive video. The old guys were familiar with it and recommended it. I haven't tried it but have one block it would work on.
They never recommended it for oil pan rail cracks - those are fatal.
If i recall correctly lock n stitch threads are "back cut" for lack of a better description and actually pull the metal together where standard threads would push it apart.

 

There used to be a shop here called Diesel Casting Service. He specialized in large diesel engine head repair for the off shore oil exploration companies. After he passed away no one picked up his customers.

 

I have a good friend who is an old time engine builder and I know that he does pin repairs to cast iron cracks. I have not been in his shop when he did the work but the final product is the same. He is a living example of a dying breed.

 

I haven't used Lock-N-Stich but have used Irontite which works about the same and is cheaper. I did 2 cracks between valve and cylinder wall and they seem to be holding.

 

I've had a couple of heads done and they lasted until I sold the vehicles. The guy that did mine has long since passed and like was said before nobody took over his business. I've got another 351C head that's cracked and none of the machine shops around here do this type work.

 

Now you know how it's done, you can do it yourself