Re: Spark plug thread repair

[DAN ANDERSON]

I went on their site to read about these inserts. I am glad to see that they are using inserts! Much better than Heli-Coils which is the brand name. Spiraling threads. I hate those things, just my opinion. They talk about their use in Triton (Ford) aluminum heads. Those spark plugs don’t use gasket type plugs. (Just something to remember). Not sure if that will cause a sealing problem, but I did notice the under cut at the top of the insert? They are also a steel insert. When we did a marine insert we always used stainless steel,for obvious reason. The top of the insert is in square with the head surface. The insert is put in with Loctite HT 400 . I can’t imagine why they would use a silicone based adhesive. (They don’t mention any adhesive on the site). We have never had an insert leak! Iguess part of this could be for the DIY application. It is hard to do professional insert installation. We were usually putting in inserts after removing broken bolts. If they couldn’t be removed successfully the the hole was enlarged and an insert was installed. Just a few more things to consider.
I don’t like inserts on spark plugs because plugs are removed often. If another head can be had I would go that way. Just my opinion!

Dan in TN