TIME-SERT® M14x1.25 Domestic Spark Plug Thread Repair kit p/n 4412E-187

Well, they're not cheap. But there's some really slick engineering in there. I had messed up one of the sparkplug holes on my Chevy SSR. Aluminum cylinder head... I didn't want to risk using some off-brand nonsense. Everything in this kit is engineered to go together. The inserts are missing the last few threads - on purpose. When you install the insert with the tool, after it bottoms out in the head, the tool rolls out thoselast few threads, expanding the insert AT THE BOTTOM, so it can't pop out. And if that's not enough, they include a little bottle of high-strength Loctite. Also, the inner and outer threads are matched, so the major diameter of the outer threads matches the major diameter of the spark plug. So if you cut one of these things in half, it would look like a zigzag. Andminimizes the size of the repair hole. It took quite a while to do this repair; I greased the tap, applied tapping fluid, started it off, did a few threads then unscrewed it, cleaned off the chips and grease, regreased, more tapping fluid. Then a few more threads, pull out, clean, regrease. Etc. This kit saved me from having to pull that cylinder head.

Easy and nearly fool proof to use. A bit of confusion on tapered verses washered plugs but once I got the correct insert the installation was clean and easy.

I've been in the industry for a while and have never bit the bullet to get a timesert kit. A little pricey but IMO its worth it if you'll do multiple repairs. The instructions were great and providing pictures and step by step instructions. A pack of new inserts is cheap, most of this cost is for the tool set. Amazing and highly recommend if you can afford it.

First time I ever used one of these to restore a thread. Awesome! Worked great. Even with the spark plug hole waaay down in there, I had NO trouble at all. Love this better than helicoils anyday!

Worked very well

Works really well, worth the additional price over a Helicoil.