How much torque can be applied to open a seized Spark Plug?

[robnicko]

Interesting. Several years ago I talked to a tech service person at a plug manufacturer on subject of anti-seize. I believe it was NGK but not positive.

He told me no need for it. Something about the metal composition of the threaded area was such that it was not necessary.

I don't use any anti seize on plugs and have not had issues.

Ive heard the same from NGK as well. Apparently some special coating on the threads is applied during manufacture of NGK plugs they said that negates the need for anti seize
The thing is with the way plugs in these motors are located, if any oil leak in the tubes has occurred and gets on the threads of the plug hole in the head and then a plug put in / torqued down the heat cycles bake that oil into a super strong thread bond that makes getting the plug out down the road very difficult.

when the plugs are out, spray brake clean onto the threads in the head and dry off with a compressor is recommended