Extractor broken off in cylinder head

Noticed today that that exhaust manifold was blowing so thought i would have a look. 1 stud missing so off came the manifold only to find 2 gaskets behind it and where the missing stud should have been appears to be a broken extractor tool as it is hardened cus I have tried drilling it with cobalt drills to no effect. Then tried to weld a nut onto the end but wont take. Have any of you got any ideas how to get this broken extractor out or if any one knows of someone in the midlands who I can take the head to for removal. Thanks Andy

Only way I've seen it sucessfully done is with a spark eroder. Takes a few hours but it does no damage to the soft head as it does not rely on heat but a powerful pulsing arc to burn away the offending item. Any decent engineering workshop should have one or at least access to one. My mate has a small one in his shed but I'm not sure the head would fit in the electrolyte tank.

Shifty cheers for the information. UP has also mentioned it so will be on the phone tomorrow

You can try using short bursts with a plasma cutter to remove most of it then either re tap the hole or drill it oversize and helicoil.

Plasma cutter on an alloy head is not a good idea. Not unless you want to buy a new head that is. Its not accurate enough or controllable and the molten metal will blow back from a blind hole straight into your face.