Posted by Gordon on Wednesday, October 22, 2003 at 1:45PM :
In Reply to: Re: Wire in head posted by Dave on Sunday, October 19, 2003 at 11:20PM :
It's a core wire,core nail,or 'sprog' used to hold one part of the sand core in place whilst casting.
The external ones get removed during fettling, as do most of the internal ones, but sometimes the internal ones are particularly long, or more commonly they get the head of the sprog embedded in the metal which makes them pretty much impossible to remove and they just get left.
If it was a small piece of steel shaped like a dog biscuit in cross section THEN you need to worry, as that would tell me the block has been cracked and subject to a physical repair.
Just to round off, early Ford GPW engines were particularly prone to cracking because of the in section at one side of the block and are hard to find these days in good condition. Presumably they just altered the patterns to thicken up the cross section in the appropriate area and the problem vanished on later blocks.