If you have a problem with the threads in your cylinder head and spark plug, this little tool might be a life saver...

We had issues with one of our spark plugs not seating right. That would normally involve a costly and time consuming repair. NOT with this little $30 tool.

It's called a thread chaser. You put it down into the blind spark plug hole, expand it a little until it engages the threads then back it out. Repeat the process a turn or two at a time until you've reached the original thread's diameter and it has reformed the threads. It doesn't cut new ones. Also, because of the grease and the fact that you're only turning it back OUT of the head, you don't drop any nasty little goodies into the engine cylinder. Took a little time, but worked like a champ. Ran the engine under load at full speed for ten minutes without any issue. Full test on Off the Range today.