I have some TTI coated headers and I want to add 8 EGT bungs to them. Is this possible without re-coating them? I am not so much concerned about the looks but I don't want to rest of the coating to come off because I ground some off to weld?

Thoughts?

going to be tough to weld them if you cant clean both sided of the weld location. There is a clamp on bung available that uses a hose clamp to hold the bung in location.

That is true, but I feel they are going to be mounted close enough to the opening that I can get in there and remove the coating inside and out.

I have seen that type of probe and I haven't ruled it out. My concerns are, leaks, and consistency of mounting. This is a street car with exhaust so I don't want them to leak. It also seems very important to mount the probes as consistently as possible cylinder to cylinder and I think that would be more difficult with the clamp style and the way these headers route right out of the head.

EGT is just a data point I want to mess with, I can adjust fuel and timing per cylinder so why not try to take advantage of it?

any bit of residual coating contaminates the weld pretty bad so you need to grind it pretty thoroughly.

You will have to CLEAN the area you want to locate the sensor.Also keep in mind the way the sensor will exit the tube and that you have the room!!!.
I went with O/2 bungs and then recoated.....
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That looks just like the single probe EGT that was in my airplane when I bought it. They work fine for leaning and reaching peak EGT at altitude at WOT.
My 260 HP 540 C.I. air cooled 180 degree opposed flat six cylinder Lycoming would start to shudder and miss a little bit while manually leaning it out before reaching peak EGT, the cockpit gauge read from around 900 F up to 1600 F is what I'm remembering now, I would lean it to peak and then richen it up 25 to 75 F from peak. That made the ride smooth and it would keep the 16 spark plugs clean as well as not waste precious 100 LL Aviation gasoline.

Jb weld will fix the leaks

i added EGT bungs to my coated headers. real easy to do. Make a stencil by drilling a piece of sheetmetal big enough to fit the bung with room for a tig weld around the bung. With a home sand/media blaster, prep the area by blasting the required spot with your stencil. Then drill & weld the bung into postion. I coated my headers black as i liked the look, so a quick touch up with VHT black paint & it looked mint.

EGT's I've had were always in the bottom of the pipe. You are not going to see where you buffed off the coating to get a good weld.

When I added egt’s last year I’m pretty sure it said app 1 inch from the header flange at 12oclock. O2 sensors are in the collector in the 3 or 9 o’clock position for moisture reasons.

Thank you for the replies everyone.