I am not very mechanically minded at all but I sent my Morris Minor for service and the garage did a great job but told me they couldn't remove one of the plugs and they thought it was cross threaded. I decided as did the originator of this thread to try to do it myself after getting the engine hot, but just as his did the plug, after tantalizingly coming out a couple of threads, then snapped off. I read this thread which I found through Google and found it helpful. However I must tell imspanners (Aug 5th 2006) that I want to enter my stuck spark plug as the most stuck spark plug of all time. No-one who tried could get it to budge with the TX45 (which seemed the right size for a Morris Minor) or a TX50 or anything else. They just cut through the inside of the stuck plug.
Perhaps because I am so naive mechanically I decided to disagree with all the others who told me the head would have to come off. I just couldn't see how the plug could possibly stay in there if I used a hacksaw to cut two grooves through the inside of the plug - it would HAVE to come out wouldn't it? So I followed the first step which was to chuck an old sweater over the plugs and fire the engine on 3 cylinders and was amazed when all the ceramic blew out just as they said it would - it almost blew the old sweater out of the bonnet! That left a nice clean hole. I removed the washer from the old spark plug which was still sitting there and after the above methods had failed as stated I set about sawing 2 grooves using a Padsaw handle fitted with a junior hacksaw blade (any other blade was too big). You need to keep the exposed blade short as it will tend to snap off in bits. Before doing this I took off the valve cover (easy, just 2 bolts) and ensured the rockers were up (I was told this means they are in the closed position and this means bits of metal won't fall inside the piston bore). Then I sawed the grooves into the shell of the old spark plug. Finally I used an old screwdriver and a hammer to knock the wall of the old plug inwards then knocked it back out and back in again etc to weaken it and hey presto the last step was to use a pair of long necked pliers and I screwed the pesky thing out. My neighbour lent me a spark plug device which I think he called a chaser, which is like a spark plug with grooves in the thread and this is screwed into the hole bit by bit to clean the thread in the head. Last step was to use a small magnet-tipped screwdriver to poke down the hole several times and bring up one bit of broken hacksaw blade and lots of iron filings.
The new plug went straight in and the car is fine. I don't want to give the impression I did everything on a wing and a prayer as I asked the opinion of 2 mechanics and neither of them baulked at the idea, just counselling to be careful - which I was. I hope this helps anyone with the same problem - if I can do it with almost no knowledge of car mechanics (but a reasonable brain I hope ) then anyone can.
