Well according to the Norvil website they are unmachined castings ...
Yes, but why were they unmachined in the first place?
The hypothesis was, they were probably scrapped for some reason, and intended to be put back into the system and re melted. But some ‘enterprising’ individual thought otherwise.
I guess we’ll never know for sure, but I personally think that’s the most likely scenario.
It happens a lot in foundries, castings get rejected for all sorts of reasons, and provided they’re rejected before any machining is done on them, there is not much cost loss. So it’s often not a high priority for management (wrongly so, but that’s another topic).
Nigel you could well be right ... but it seems odd that a batch of 750 and 850 rejected castings have been stashed away to suddenly reappear almost some 50 years later. That takes forsight .
I dont have an earlier cylinder head to compare ,but the RM1 fitted to mine I would have thought was sand cast , one wonders whether this was so back in Dominator and Bracebridge Streets days? Certainly such a complex mould calling for a split pattern and possibly 5 cores would take a lot of skilled and expensive time to set up so every incentive not to throw failures back in the pot.
But isnt the suggestion they are coming from a foundry in Stoke?
What can I say, except, the way they have treated me, that would be a resounding "over my dead body".