Posted by Stick on 27/06/2009 18:52:37:
… I hadn’t given any thought regarding hard spots in the cored bar, …
To be honest i has never seen hard spots in cast iron in the used car parts such as in brake disc, cam shaft or flywheel, they are of good quality cast iron.
Do not unharden the hardened cam in camshaft!!! You will get hard spots in soft cast iron between cams after the camshaft has been redglowing.. It is impossible to unharden the cams, they will be still hard.