SMOG Pump plug
 

I had one of these blow yesterday at a DE at Summit Point, WV. I found another loose. I checked the other and all were tight. I presume the heating and cooling of the cylinders caused them to work loose. I don't remember if I used Loc-tite 271 when I originally installed them but I put some of this one when I replaced it. How common occurrence is this and what is the prescription for guaranteed success and life long plug plugging. The problem and the solution.

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Was hoping for some feedback and while noodling hit the obvious. Loc-tite is only good for 250degrees or so. Way under sourced for this application. Not sure what else to use tho?

Long term, have the holes welded shut when next you redo the heads.

Otherwise, torque them in tighter. That's a nice head on that bolt.

I used to have these problems with what I used - a 10mmx1.0 bolt with head cut off and a screw driver slot cut into the end with a hacksaw. When I switched to Allen head screws I could bet better purchase with the Allen wrench and crank them tighter.

I've used the orange Loctite you use to seal case halves/cam carriers. It withstands quite a bit of heat and seems to have some locking effect.

But you can crank pretty hard on these hex headed ones. Ought to make them stay put.

You could also drill through the heads and safety wire.

Walt Fricke

Also, I don't see why what looks like a copper seal ring is needed. The threads themselves do a fine job of sealing, especially with some goop in them.