After ruining a few lawn mowers (and maybe a Honda civic) by cross threading plugs and other Sparkplug miss adventures,  I have finally learned to coat spark plug threads with Milk of Magnesia.  Below is some great stuff about plugs, threads, heads.. etc


http://speedtalk.com/forum/viewtopic.php?f=1&t=22136

Why don't you do something really novel, like learn how not to "cross thread" things.    

I use anti-sieze on spark plugs in any type of alloy head . . . but anti-sieze doesn't do anything for cross-threading.  It really does nothing for you when you put the plug in . . . it's 20 years later when you try to remove it that the anti-sieze pays off.

I think I cross threaded the civic while sticking a hot plug back in a hot head. It was a long time ago.  I still have the screw tool that refixed the threads (Forgot what its called).

When I was a 10 or 11, we had this powered reel type lawn mower that I would rope to a wagon and 6 kids would hop on the wagon and I would pull us around the neighbor hood.  I can't believe how dangerous that was with the reel blades all spinning. I have night mares about it  after all my current safety training. I bet we were all bare foot.

  Back to the story.  A few years later I was trying to build a go cart and was messing with that antique reel motor and I either ruined the engine cross threading or with a cheater bar after I forgot the righty tightey lefty loosey rule and completely ripped out the plug from the head.  JP weld is good but  it wont hold a plug in a head.

 I been plug shy ever since and Always add some oil to the threads so I can gently screw them in.  Now its milk of magnesia on threads

 Stupie has one Cyl that the helicoil comes out with the plug.  I'm not taking #1 out ever again