cleaning up the slant six head

I am hoping to be able to locate a re-search paper describing the above that was printed in 1924. With any luck I can provide a copy of the original findings. Here though is a brief synopsis of that paper provided to me by again another member of a different forum.

Its description thus far describes ( the symptoms ) what I have come across to the tee.

It is called Graphitic Softening, it is peculiar to high carbon cast irons. The acid ate the iron crystals, leaving the graphite skeleton around them, which preserves the overall shape, but is soft and easily damaged/abraded. The iron is still there, but it has been converted into colloidal iron (hyper fine particles). When you let it dry out, they support the graphite, so it seems hard again however, the metal has in fact been damaged, it is now very brittle and weak.