The sparkplug and cylinder head can take a serious heavy loosening torque. You just need to have a big enough tool.twinfalls wrote:Stuck stuck.
Doesn't move any bit either way.
Once you have gotten any movement at all, you are on your way. You can "save" the aluminum threads with lots of oil as you loosen and tighten in small increments.
Get it to loosen. Use serious heavy duty tools and plenty of oil/penetrant.
Get a big socket with a 1/2 drive extension and a 1/2 breaker bar.
Wet the area with whatever penetrant you have.
Bang the hell out of the extension and socket and breaker bar with a big hammer.
Now loosen at least 5-25mm.
More penetrant.
Tighten a little.
More penetrant.
Loosen a little more than last time.
Tighten half that.
Loosen a bit more.
More penetrant.
Tighten half that.
Loosen a bit more.
Bon Travail!
Colin