Timesert, Not Helicoil for Sparkplug Threads

   After 70k miles, and constant engine fiddling and spark plug reading, the sparkplug thread on the right head of my Lemans IV was worn out and partially disintegrated. While I had the heads off, I had the cylinder head shop install a Helicoil in the head. That lasted all of 2000 miles until, one day, the Helicoil pulled out, uncoiling as I removed the sparkplug. This time, I used a Timesert insert. So far, so good.

Ed Milich