I was changing the spark plugs on my fiesta, but me being an idiot I over tighten one them and it snapped. How do I get the other part out? Need my car for Friday. 

 

Large stud extractor.  

 

You were lucky the threads didn't strip! Then you're really stuck having to tap out the head and use a threaded insert. Make sure when you drill it out that you make sure there's no swarf left anywhere. One tiny piece could scrap the engine so no pressure.

Oh well lesson learnt, use a torque wrench next time. You might not have broken the other plugs, but it's easily done when removing them at the next service.

let us know how you get on. I am interested to know if large stud extractor works. I am wondering if the stud extractor will push the sides of the remains of the spark plug outwards making it tighter in the threads and harder to turn.

is it tight now, or can it be tapped round with a screwdriver, or turned by pushing a tight screwdriver into the hole (but not pushing so much that it pushes the sides outwards and hence tighter in the thread

 

On my GS550 motorcycle one of the spark plugs snapped like yours when I tried to undo it, after I had not used the bike for 20 years-  the way I did this :

I used a jigsaw (an electrical saw not a cardboard 1000 piece puzzle). But the problem was getting the jigsaw close enough to the hole. I put a junior hacksaw blade in the saw. Carefully I sawed a groove down one side of the hole trying to judge it so I did not cut into thread too far. Then I did the same thing on the opposite side of hole but not cutting so deep. Then I used a hammer and long screwdriver to kind of fold the remains of the spark plug in, folding along the line of the 2nd cut. This enabled me to get it out as it was now loose.  I then used a magnet on a piece of wire down the hole to clean out the iron filings from sawing. But I then got worried there might be more in there so I bought a small USB camera on ebay and using it on my laptop I could see in there (camera had small light on it). when I was satisfied I had done it best I could I put a new spark plug in and all was fine after that.

I fee your pain, that feeling as it snaps, not sure how to describe it

also looks to me like a bit of white ceramic may have come off

 

 

Hi Tom, I used to do lots of these when I worked in engine remanufacturing, (I am now retired) if you have the correct size stud extractor it may come out, if the electrode is still on the spark plug be careful it does not drop inside the cylinder. The other way is make sure the piston is down then drill through with the correct tapping size for the spark plug thread (With plenty of grease on the drill bit) then crush the shell which is left on the thread with a small chisel, long nose pliers are used to remove it. Bring the piston up with a socket on the crank pulley and put a small magnet through the hole to pick up any bits of metal still in the cylinder.

Hope this helps.