i need help with a massive problem. i was taking the exhaust manifold off my aluminum head today and one of the studs broke off deep in the head (none of it protruding). i drilled it and began using a screw extractor to remove it when, oh yes, the screw extractor broke off inside the hole i drilled in the stud. when i attempted to drill that out, it simply laughed at my carbide bit. apparently it is too hard to be drilled out. in addition, two other studs stripped the threads right out of the head. yeah, this has been a really bad day. my intent is to drill and helicoil them all but i would like to hear what somebody else has done to remedy such a mess. i would like to do it with the head still in the car if possible whereas i am able to reach them with a drill. what drill bit can i use to go through extremely hard steel? wondering if maybe a dremel would work but not sure which bit. any input from the experienced would be appreciated.

 

too late now but easy outs never work, or very seldom work. might try welding a nut on the stud. if you can't get to the stud you could grind away the aluminum and then weld nut on, after stud is out weld the aluminum back and redrill and tap. might want to invest ina can of antiseize and a torque wrench for aluminum heads.