Performance Tool W86910 Spark Plug Repair Kit M14-1.25 Thread Size & HSS Tapered Reamer, (3) 503 Stainless Steel Inserts

Very good quality it worked very well. Chainsaw is running very good now.

I used this kit to repair a plug thread on an air cooled VW head. It works pretty well. I gave it 4 stars because it does what its supposed to but the inserts do not lock into the head like a helicoil would. Its not a big deal but I cleaned the threads with brake cleaner and used high temp RTV when I set the insert. I used never seize on the plug when I threaded it in and when I removed the plug a couple of days later the insert came out with it. No biggie, I just put the plug back in with the insert on it but I wish it had a better way to lock the insert in place.

Got the job done. Requires some skill to use. The alternative is to buy the oversize tap and appropriate drill and the insert thread adapter of proper length. Likely I will not need to perform this operation again, but I could. This method would only work on an aluminum head. Cast iron would require drill and tap. One last thing. The conical spreader punch forces the insert's knurled threads into the aluminum to keep the insert from turning once it is positioned properly. The line between deformation to prevent turning and deformation that prevents spark plug installation is fine. You have to hit the punch pretty hard to get the insert to bite. You might want to deform the inside end of the insert, which requires head removal.

Worked perfectly, easy to install, the threads matched up,(yes, some don't) and it's holding strong.

My mower kept popping the spark plug while in use. This kit gave me new, clean threads for a new plug. Simple, cheap fix.. saved me from buying another mower! Tip: use lots of grease when drilling new threads

Details follow. Worked okay for me. The tool includes a cutter that precedes the tap needed for the insert. It’s about the same angle as a typical drill bit. Given its large diameter, it takes about 50 pounds force that you manually exert. Keeping it very straight is important or the insert will not be square and the spark plug will not seat properly.

Quality part, heavy duty part, works as should

Nice kit tap works well but I used this for a stripped oil drain plug on my motorcycle and this didn't work for me, no matter how hard I hit the setting tool it it would not lock in and would unscrew when the oil drain plug was removed.I'm not sure what I can do now.

Excelente opcion para roscas de bujías dañadas, la primera seccion entra en la vieja rosca lo cual permite tener una alineación perfecta y el corte del machuelo es con precisión

Did the job

I repaired an older small engine with this tool... tool worked well and did the job ... I left the head in place , removed the spark plug , hooked up a vacuum cleaner exhaust to the intake and pressurized the cylinder... then cranked the engine until air was exiting the spark plug hole and the piston was almost at the bottom ... slowly re tapped the spark plug hole to take the insert ( turn in 1/2 a turn , then back out 1/4 turn to clear the chips) threaded the insert onto the old spark plug to install it. then removed the plug and staked the insert in place with the tool. happy with the results