Stripped Bung

[sperry]

Originally Posted by cody

Oh you want on the list too? I'll see what I can do.

No thanks. I'll stand by my statement that I would rather weld a proper bung on there. I like having an EGT.

[Dean]

I still would have gone to Home Depot and spent $.12 on a normal tapered NPT plug. Maybe add a little bleach to increase oxidation and screwed it in there and let it rust itself sealed.

Maybe a piece of bailing wire or two to make a champagne cork cage to keep it there just in case.

[cody]

LOL @ Dean. It's stripped good. The plug would not have bit. I didn't know bleach causes rust. Should I coat the threads of the bolt with that before screwing it in?

I like having an EGT too, but the probe is fried and they don't make replacements. I'll probably search around to see what others with the Omori EGT gauge have done. But it's in the wrong manifold so I'll tap the driver side if I do end up getting a replacement probe.

[Dean]

Bleach is an oxidizer. Spray some on your brake rotors, they will rust in minutes.

If it wasn't upstream of the turbo, I'd suggest throwing a couple pieces of bailing wire in there to act like wooden matchsticks in a wallowed out wood screw hole.

[cody]

What do you think's holding it in there now?

Originally Posted by cody

What I ended up doing as a temporary fix is I used this Screw Hole Repair stuff I had picked up at Harbor Freight a while back. It’s just thin sheet metal that you cut into strips and put into the hole to act as a shim. I experimented with it to ensure it held up to the screwing back in process and it seemed to. But I couldn’t get the hole to seal completely and pass the soapy water test.

I’m tempted to just leave it since I really don’t think it’s losing much exhaust, but I won’t be happy with that. What if it blows the probe out at an autocross or somewhere else because the hole repair metal just melts…or whatever.

[cody]

I'll tell you one thing, I'm definitely losing less exhaust out through the probe now than I was through the UP gasket I just replaced. The car feels much more responsive (and sounds better too).

[AtomicLabMonkey]

Originally Posted by cody

Alright, I think R&E set me up right with a short grade 8 bolt (1" long I think), a grade 8 washer (to hopefully help seal the bolt head to the header, and a nut to re-true the theads after I shorten the bolt to about 1/2". I would have preferred to stick with pipe thread, but he didn't have pipe thread plugs in an apropriately larger size in grade 8.

I have the correct size tap thanks to my coworker (and it's Craftsman so I don't have to worry if I damage it). The drill bit I have is a 1/64th of an inch too narrow, but I think that's fine.

Anyone see any issue with any of this before I go at it?

Thanks to the 3 of you that offered me taps.

Wait.. so you're going to ram an SAE threaded bolt into an NPT hole to try and plug it? Am I reading this right, or did I get confused (entirely possible) somewhere along the way? If so, that is a Bad Idea. NPT holes need NPT plugs.

And don't worry about bolt/plug grade, this isn't a structural application and I assume very little torque will be put on the fastener, so it doesn't much matter.

[cody]

No the the bolt I'm using will match the newly cut threads in the manifold perfectly.

The only reason I went with grade 8 is because I was concerned with thermal expansion and had no idea what grade would be best but all of the OEM fasteners on the manifolds are grade 8 so I figured it couldn't hurt. Obviously cost wasn't a concern at $3.22.

[AtomicLabMonkey]

Okay. FYI the bolt grade will not affect thermal expansion. You only need a certain grade if you need to develop a torque requiring its strength.

[cody]

Well, then I wasted a buck. Hopefully the guy at R&E was right and I'll be able to cut the bolt with a cut off wheel. Should I consider a lower grade bolt or should a cut off wheel work. I have dremel cut off wheels and an angle grinder.

[AtomicLabMonkey]

An angle grinder with a thin cutoff blade will work just fine. You need a metal cutting blade for whatever size grinder you have, you can get it at any hardware store.

[cody]

I bought "cut-off wheels" for my angle grinder and they worked fine for cutting open struts for Koni inserts. Those should work eh? Or do I need an extra thin metal cutting blade?

[Kevin M]

They're fine, just don't rush it. You might want to make sure you have the reinforced kind though, or you'll go through like 25 of the crappy discs by shattering them.

[cody]

I don't think they're reinforced.

What do you guys think about spraying some high temp copper gasket spray I have on the bolt to help it seal and stay in place? Too hot to matter?

[AtomicLabMonkey]

The one I have here in front of me is .040" thick, but anything rated for metal will work. You could use a thick grinding wheel if you wanted, it'd just be extra ugly and you might have to do more cleanup on the threads.

[cody]

Gotcha. Should I leave the bolt bare or spray it with high temp copper gasket spray before installing it? Can't hurt right?

[AtomicLabMonkey]

I don't know what temp the spray you've got is rated for, or how hot the manifold casting gets during operation, so it's hard to say. My concern would be goop melting away and doing something to the turbo, but I dunno if it would be an issue or not. You might want to try finding a copper crush washer that will fit the bolt instead, to be your sealing surface, instead of gooping some spray in the threads.

[cody]

I think what I'll do is only use the copper spray on the threads that are closest to the head of the bolt and on the washer. I was wondering if a copper washer would be a good idea given the heat involved. The guy at R&E recommended one but had no idea if it would melt.

[sperry]

This may officially be the longest thread on the internet about your bung hole, Cody.

....wait, nevermind, there's that other thread on that other site I almost forgot about.

For god's sake, plug that damn hole already and see if it works... more talking about it isn't going to get you any closer to being leak free!

[AtomicLabMonkey]

Copper has a 1900+deg melting point, so I'd say it's worth a shot.

[cody]

Awesome. If the exhaust gasses are only ~1600* hot the metal should be cooler. I'll definitely use a copper washer then, maybe one on either side of the grade 8 washer and then I might not even need to cut the bolt. I'll play with it.

[Dean]

I would not use any "spray" or a copper washer. With goop of most any flavor, the carrier will carbonize.

Copper washers may not melt, but the become quite soft and deform at forced induction temps. I tried copper gaskets and they were far worse than the OEM steel from a leaking perspective.

[cody]

Agreed on the copper gaskets. The one I had between the UP and PS Ex. Man. lasted about a year before it blew out and looked like a volcano. Then the one I had between the Ex. Man and head started leaking shortly after. What a headache.

However, gaskets are exposed to the exhaust gasses while the copper washers will be on the outside of the pipe where, I imagine, it's much cooler.

[Dean]

They expand and contract at a different rate than the steel around them. that is what loosens things and causes leaks.

[cody]

Did I mention I'm going to have a rabbi bless it first?

Yah, I dunno. Too many options and it's not my expertise so I guess I'll just stick with the original plan and just use the single grade 8 washer. I'd like to at least coat the washer with the copper spray, but I'll have to read the can first and see how high of a temp it's rated for.