EGT sensor plugs

[Jim Caughlin]

As a custom header builder, I often am requested to install 1/8 NPT bungs for dyno work. Obviously, these need to be plugged when not in use. Over the years, I have tried aluminum, SS and MS plugs along with various silicone, anti seize and tightening methods. It always comes down to cussing and praying when its time to romove the seized in plugs. I just spent an hour drilling out the plugs and retapping the bungs on my own headers so my question is does anyone have a solution to this problem? Please real life answers only, no "I read it in Hot Dog magazine" stuff.

Jim Caughlin
SS 6019

[FED 387]

I used Brass plugs with a light dab of Anti-Sieze-Of course I did not leave the plugs in "forever" either--worked for me--Comp 387

[Chris "drooze" Wertman]

Dumb question but why are you not using the outer EGT where the Male is on the Header and a ferrule and cap nut are used ?

When not in use they are just capped ?

Seems like there is less turb with exhaust passing a 1/8 in flat hole than a 1/8 npt female thats plugged on the header.

Or do I just "not get" it and the question ?

(and no harrasing me about "pimping" for our sponsor, they are the only ones that had both and I knew where they are and the "watermark" their images because people in their business have a real big habbit of stealing em)

BUT is this what you are using ?



And why not (and Im really curious as I may learn something)

Why not use something like this ?



Then just cap it with this...

Originally Posted by Jim Caughlin

As a custom header builder, I often am requested to install 1/8 NPT bungs for dyno work. Obviously, these need to be plugged when not in use. Over the years, I have tried aluminum, SS and MS plugs along with various silicone, anti seize and tightening methods. It always comes down to cussing and praying when its time to romove the seized in plugs. I just spent an hour drilling out the plugs and retapping the bungs on my own headers so my question is does anyone have a solution to this problem? Please real life answers only, no "I read it in Hot Dog magazine" stuff.

Jim Caughlin
SS 6019

[Jim Caughlin]

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

[Chris "drooze" Wertman]

Well take this for what its worth, Im gonna get "crap" for it people saying BS this BS that, Ill let the old man chime in on that if it gets to nasty.

In my Prior life , Prior to my sons birth 13 years ago I was a Plumber and Pipefitter, mostly commercial mostly High pressure steam and chemical.

I was the youngest Commercial Journeyman at our local 219 at the time I didnt have to go through the apprenticship program. BUT that was because not because I was 4th generation P/P on my mothers side but rather because I learned from the Old timers like my Uncle, My Grandfather and my Cousins, funny its kinda why I got stuck in steam and Chemical I was one of the few guys around especially under 50 that had any clue what some of the tools were let alone how to use them.

All that being said, there was a high temp chemical line that was a BEAR and it was something there was a npt plug on.....we had to pull it to drain it, I cant remeber the alloy, Chroloy, Halestoy C....no matter....BUT for some reason even though no matter how "indestuctable" the alloy was a combination of heat, pressure (it was part of a chemical process for an exothermic reaction that got HOT when running) The damm thing would never want to come out, and it had to on a regular basis. It was at Barberton PPG plant....

AND we werent allowed to use ANY type of sealing compund on it, it wasnt a standard NPT thread but a long odd type of tapered plg, this was a chemical reaction that was part of Phosgene production or something....(we used to have to wear badges there)

So I was having coffee at my retired uncles about a mile away after that job one day....and BITCHING about it. Tight space, no good angle, I wanted to redo it, but no way wasnt an option....

He asked where, i told him (he had done the system install years before) he said, go back and tell em you forgot a tool and look up on top of the I beam about 4 ft above the fitting. I said Ok....what am I going to find ? He said just go and see if its still there, when you see it youll know what to do with it.

So I jumped in my truck and ran back down, up above was an odd, very old, and strange looking paper packet with thin foil of some type of metal in it. And some thread marks in a piece where it had been wrapped around and tore off.....it was strange stuff, thin, ductile, but not copper, I smelled it then thought who knows whats on this ****..(I was actually worried for days) but metals all smell different, and I know many, this not so much it was a goldish but it could have been a tin silver copper alloy , suffice it to say.

You would WRAP the plug in the foil (which apparently wasnt reactive with the chemicals) and put it in. It came out slick as could be next time.

Someone had years ago forgotten that "trick" and how to do what the old timers knew.

I did years later find some copper foil that I would use in similar situations on steam and other stuff (never chemical) and always came out nice.

That being said, the EGTs are higher but copper foil if its pure and soft enough, the more pure the softer it is.

Oh and I did try something ONCE on a very large thread pitch plug, a wire strand around the bottom of the thread pitch, seemed to work better than nothing at all on that one.

Just some long winded thoughts and reminiscing........I miss "honest" work......

Originally Posted by Jim Caughlin

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

[Peter Ash]

Jim

Have you tried several wraps of teflon tape?

Peter

[Bobby DiDomenico]

Originally Posted by Peter Ash

Jim

Have you tried several wraps of teflon tape?

Peter

Peter,

Regular Teflon Tape?

[Peter Ash]

Originally Posted by Bobby DiDomenico

Peter,

Regular Teflon Tape?

Bobby

Yes, the pipe fitter/plumber off the shelf stuff!

Peter

[Jim Caughlin]

Peter,

I assume the teflon tape melts, all I know is that it is gone at some point. Same thing for antiseize, probably a good idea for initial installation but I assume it melts as soon as the engine is fired. I've seen antiseize melt while welding so I know for sure that it won't handle the temp. I'm leaning toward the brass plug idea with a little orange RTV and minimal tightening as an experiment.

Jim

[SSDiv6]

Originally Posted by Jim Caughlin

Peter,

I assume the teflon tape melts, all I know is that it is gone at some point. Same thing for antiseize, probably a good idea for initial installation but I assume it melts as soon as the engine is fired. I've seen antiseize melt while welding so I know for sure that it won't handle the temp. I'm leaning toward the brass plug idea with a little orange RTV and minimal tightening as an experiment.

Jim

Jim,

The Teflon tape will not work and there are anti seize products that will go to very high temperatures.

I would recommend the following Anti-Seize compounds.
We use them in high temperature turbine engine environments.
You may be able to get these products at an industrial supply store.

Loctite Copper Based Anti Seize P/N C5-A

Loctite Nickel Grade Anti Seize P/N 77124

Dow Corning Molykote P37 Paste (Good up to +2000 Degrees F)

Grainger Nickel tape Sealant 2TE44

Do not use any of the Bostic or Jet-Lube Anti Seize products.