Dont see how a magnet would help unless you have cast iron heads.

 

heli-coils are fine but i would use a thread insert. the heli-coil is just that a coil and it too can come unwound in the head. the tread insert uses locking pins to secure it in place and will be stronger that the heli-coil. a note on never-seize: only use a small spot about two threads up from the end of the plug. this will ensure you do not foul the plug. a better product to use is desco 220. this is a space age lube and unlike metal particle base never-seize, it will not carbon up the treads and seize them. i would bet the shop mechanic over torqued the plugs and stretched the threads in the head which broke off and thread locked the plug when you removed them. a fantastic penatrate to use is aero- kroil made by nano industries.

 

Helicoils are thread inserts.

The "thread insert" you are refering to is a Time-sert or Keensert.

All of the above are brand names.

 

damm, sorta surprised that you didn't warm up the motor, then shut it off, and spray some pb2 down into the threads. that's why i use the anti sneeze on the threads before installing the plugs, and using the torque wrench. i never have had problems with plugs doing it that way. one guy said, use a magnet to get out whatever is left of the threads? must be a special sort of aluminum magnet that he's talking about, cause surely you didn't lose threads off of the spark plug. good luck with fixing it. i'd try to let the dealer who caused the problem help before you tear into it.

 

I"d pull the head and go from there. Do the job once correctly - piece of mind.

 

I really was not thinking about it, I was not thinking about an aluminum head strictly. Thus, no magnet would not work on a Harley. My point being, a long time ago, a shop is not going to repair it knowingly causing damage.

 

Pay me now or pay me later, I would pull the head and fix it right. That's me. Because it will F*** you when you least need it too.

 

Sounds like two new jugs with SE pistons and a fuel pac would do the trick.

 

Time to face it Dude - you're screwed. No pun intended. Talk to a good automotive machine shop before spending any money on helicoils. They work well in many applications and may do the job here but I really think it's time to look for a new head.
I don't know of any aluminum head manufacturer in the automotive end that does not insist on antisieze on sparkplug threads. Of course you don't need to slather it on, just a dab and you're good to go.
Chances are slim to none that after 10,000+ mi. the offending dealer will help at all.
Good luck and I hope this doesn't happen to you ever again.

 

I had this happen on a new remanufactured motor fr HD. The mechanic got it out w penetrating oil and just ran a thread chaser down a couple times and everything was fine.