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Jim Caughlin · 04-06-2010, 01:41 PM

The upper photo is exactly what the EGT fitting looks like, and threads into a 1/8 NPT coupler. When not in use, it is removed and a plug of some sort seals the hole. The lower photos are a different but less common fitting. I have to accommodate the common fitting that will adapt to most cusomers expectations. You do have a point in that straight threads don't seem to be a problem, The straight threads on O2 sensor plugs seem to come out OK even after considerable run time. Clearly, the seating into the tapered pipe thread causes the problem. My best success has been to use the orange high temp RTV and not tighten down the plug. Anti seize seems to 'cook off' fairly quickly in my experience.Haven't tried brass as Comp 387 had suggested, probably worth a try. Worst case, it would at least drill / tap out easy if it seized. By far, SS is the worst for seizing.

Jim

04-06-2010, 01:41 PM	#4
Jim Caughlin Senior Member Join Date: Mar 2002 Location: Woodburn, Or Posts: 685 Likes: 82 Liked 805 Times in 245 Posts	Re: EGT sensor plugs The upper photo is exactly what the EGT fitting looks like, and threads into a 1/8 NPT coupler. When not in use, it is removed and a plug of some sort seals the hole. The lower photos are a different but less common fitting. I have to accommodate the common fitting that will adapt to most cusomers expectations. You do have a point in that straight threads don't seem to be a problem, The straight threads on O2 sensor plugs seem to come out OK even after considerable run time. Clearly, the seating into the tapered pipe thread causes the problem. My best success has been to use the orange high temp RTV and not tighten down the plug. Anti seize seems to 'cook off' fairly quickly in my experience.Haven't tried brass as Comp 387 had suggested, probably worth a try. Worst case, it would at least drill / tap out easy if it seized. By far, SS is the worst for seizing. Jim