Hi. I blew a core plug (2.25 petrol engine) a couple of months ago which turned out to be a screw in aluminium type about an inch and a quarter in diameter. It is one of two that resides just behind the manifold. Although the manifold is off and I can see the hole , there is still some of the origional left in the hole that I can not get out. Idealy I think I need a tap to re-cut the hole or even a bolt of the same size might do the trick.
Problem is my friend got me a replacement plug from a dealer near him but I have no idea what thread or size tap I need to ream out the hole ( If indeed that is the correct way to handle this task )
Any ideas please ???