Paging inconel stud crew
 

Because my inconel studs are backing out with just street driving. The car has not seen the track yet. Removed them, put MORE resbond on them, and they still came out.

Obviously the studs are not the problem, I'm trying to figure out what is.

Do you guys who have inconel studs have it coupled with other anti backing out measures? A couple things I could think of:

-A manifold where the studs don't see direct exhaust.
-Is your downpipe supported in anyway, like the stock one with the bracket that bolts to the tranny?
-Do you have some kind of mount to support the turbo?

My setup consists of a begi log manifold, downpipe that is not bolted to the tranny, and turbo is not supported by anything.

Opinions/ideas/name calling?

I'm going to swap out manifolds with another begi piece and see what happens, but I'm not keeping my hopes up.

Custom manifold, studs do not see direct heat. I'm not using resbond or locking hardware, and have not had a single problem street driving.

I haven't got my turbo setup installed yet, but after having a good read through the EPIC nuts/studs loosening thread this is what im installing.

I tapped my Begi manifold out from 8mm to accept M10x1.5 Inconel studs, some Resbond 907TS threadlocker, and Stage 8 fasteners. From what others have said about this setup I hope I shouldn't have a problem.


https://www.miataturbo.net/attachmen...ine=1329021449

^ you are installing my exact setup. Realistically, you shouldn't have any problems. I'm just unlucky and/or doing something very wrong here.

On my install (street driven so far, ~10K miles turboed), I discarded the studs and used 8.8 bolts drilled for safety wire. I used Inconel safety wire. Haven't had any issues.

I'm curious why everyone uses Inconel studs with locking nuts rather than Inconel bolts? Obviously, if you could use Inconel bolts with safety wire, you would be all set. Studs + Resbond + Fancy Locking Nuts sure looks overcomplicated to me. As you've discovered, studs can back out.

Don't know whether drilled Inconel bolts are available or whether they can be drilled without using some kind of special bit. Maybe that's the reason?

The studs are custom made too, so having to customize bolts by drilling safety wire holes shouldn't be a problem. Bolts will back out the same as studs, I believe studs were chosen because the stage 8 locking hardware is easier to use than drilling a hole. Plus studs are cheaper to manufacture than bolts.

OP, you are or are not using locking hardware along with your resbond?

I am, I'm using exactly what green_comet is using. Along with resbond.

It's not physically possible to install bolts into at least one (possibly two) of the holes on a normal T25 turbine housing. Also, using Inco safety wire on steel hardware is like rearranging the deck chairs on the Titanic. ;)

Abe, didn't we chat on the phone about this a couple of months ago? You said the studs wiggle in the threads even with almost all of the threads engaged in the manifold? I am pretty sure the threads in the manifold are your problem.

This is what I was about to post, as I've experienced this on one of the cheap cast manifolds I had - which ended up stripping the bolts (not inconel) and manifold threads. Can OP heli-coil flange without experiencing any thermal expansion issues from the helis?
FYI, I've tracked TSE's kit without ANY loosening - which is freakin awesome not dealing with it...

I'm a little worried you guys say that, I just checked the studs in my manifold and they all wiggle around a little no matter how much thread is screwed in. They lock up when they bottom out, but other than they they wiggle around a little.

Which is why I hope this second manifold works.


Any more info about your setup? Turbo/downpipe brackets/mounts, etc?

This is exactly how mine are. They're tight when they bottom out. I'm seriously hoping sav is right.

I'd rather see Inco bolts myself, scratch the locking hardware, and EDM drill.

That would be cool but it would be physically impossible for me to use bolts.

Hmm, I wonder if some manifolds are threaded with inferior taps. I know different classes of threads can have looser tolerances. Do you know what class thread your studs are made to Sav?

Because of the damaged manifold or something else?

I would only be able to fit a bolt in 2 of the holes, the other 2 would end up hitting the exhaust housing.


I'd like to know this too.

I'll ask Bryan's question again, since I'm curious. Any issues with Heli-Coils in this application? If not, there shouldn't be any problem re-drilling the manifold since you'll need to drill a larger diameter anyway. It sure sounds like your current threads don't have the correct dimensions.

Nobody here torques the studs into the mani after the shoulder seats? I do that with about 1/2 of the torque I use on the nuts, with a stud driver. This torquing also pre-loads the stud, in theory allowing the stress from the nut to distribute along the stud's threads.

I used a BEGI log mani before my ETD mani, and never had a problem with steel studs on the street.

To the OP, how hard do you drive on the street / Hwy 9?

I torqued the studs in. Probably with more torque than that. The torque specs on the instructions say to torque the nuts to 15 ft lbs. Would overtorque cause these to come out? (I'm not sure how but I figured I'd ask) Measuring 15 ft lbs with a wrench in your hand is kind of hard.

I stopped going on hwy 9 after my first track day :giggle:. I don't really drive that hard on the street, my commute right now is a total of 10 miles a day.