Copper Clad Exhaust housing Lock Nut
 

Hey all, I attempted to remove the turbo manifold, and immediately noticed that a stud was coming off the housing, instead of the the nut. I called it a day, and purchased 4 new OEM studs. The current nuts installed are not OEM, so i am wondering if I should go with OEM nuts, or go with copper clad lock nuts, or something else. I want to do this job once, not really looking at having to re-torque things down the road.

Anybody with experience or suggestions on this matter, please chime in!

I went with 4 oem studs and nuts. I made sure to use copper anti seize on all of it. I assume you're talking about a single turbo set up. I've had to remove mine a few times now and it was without any difficulty. The oem nuts are locking and low profile. I don't see any reason why the copper ones wouldn't work just as well other than clearance but if you're single turbo then the flange on the manifold has plenty of space. Personally I would suggest using the oem stud and nut.

I had copper and i had to heat up with a heat gun to remove the nut and it wont go in anymore the nut from the stud cause came off the housing. Get OEM, the copper one will lock up or mess up.

You sure it was the same thread pitch? They're supposed to "lock" but not to the extent you described. What you described sounds like a cross threaded nut

You could use silver plated k-nuts, they're at least reusable a few times compared to the stockers. They're often used on v-band flanges and turbo to manifold attachments, problem might be finding 10x1.5 in the imperial homeland!

Lots of conflicting info here, but I've personally been using the copper clad exhaust nuts for probably 15-20 years on my cars, friend's cars, you name it. They've always come right off and have never pulled or damaged a stud on me. This is on cars daily driven with lots of miles as well.

They should spin on easily but require a socket or wrench once the stud gets to the top part of the nut where it is crimped over.

I've never used the Mazda nuts, I think newer ones are less aggressive than the ones that originally came on the car, but the copper nuts work so well and you can get a sack of them for cheap, there's no good reason not to use them.

This is an excellent source for them -

https://www.clipsandfasteners.com/Nu...teel-s/713.htm

They have the 8 and 10mm sizes if you are pulling the stock turbos. Also they have ones that are proper 14mm wrench sizes, not 13 or 15 or some foolishness.

Dale

All, thanks for the help!

Yep, this is for a single turbo setup, I need to pull the manifold in order to re-wrap it with the exhaust tape, the one that I installed 10 years ago is finally coming apart.

DaleClark, thanks for the link! Do you use a washer with those copper clad nuts? The M10-1.5 one in that link does not have a flange built in.

I've always used brass nuts and Nordlocks.

Give some thought to factory manual torque specs if you use anti-seize or use a different type of nut. When you lubricate threads or use a regular nut in place of prevailing torque type it reduces the torque required to create the desired clamping force / elastic deformation of the stud. In some cases you can permanently stretch or break studs if you don't reduce torque. That is not a stud I want to break.

Side note - Nordlocks are awesome! Used them for the cv axle bolts on our E28 lemons car that kept coming loose. I would definitely consider them if re-attaching my exhaust mani, but they may be overkill here.

You can use a washer to help distribute the load, not totally necessary though. You may not have enough room for a washer to fit.

Thinking about it I have always used the ones without the flange on them.

Dale

One thing to keep an eye on is the thickness of the flange and whether or not you may run out of threads on the stud. Maybe one of my studs is in backwards, not sure, but I was bottoming out on the stud where the threads ended. I have a couple of washers to ensure I have full engagement and to distribute the load as Dale mentioned. I was able to find some S/S with a smaller footprint at a local hardware store that has a good selection of metric hardware.

Ordered the copper clad nuts M10-1.50, wondering if you guys are torquing them to the same ft/lbs as the OEM ones? Alexdimen comment on torque got me thinking...

Torque should not change based on the style of the nut or type of metal used for the nut, it changes based on the use of anti-seize. I lowered my torque by 15% below FSM recommendations due to using the anti-seize. I also used high quality nickel anti-seize, which is used for nuclear reactor work, due to its superior longevity and very high heat tolerance.
Mike

Prevailing torque requires some torque input just to overcome friction between the metals so I would expect some reduction in effective torque on the nut. I personally wouldn't trust the torque specs in the FSM for an application that used a prevailing torque nut after swapping it for a standard nut or Nordlock. You never know if the engineer took the prevailing torque into account or not.

Sounds like you're using prevailing torque type just like factory so it's really a non-issue.

I would definitely reduce torque for anti-seize as that is established practice.

Ultimately I didn't even use a torque wrench on my exhaust stud nuts because I didn't like the way it felt with my torque wrench as I got to the spec. There are other factors involved there that i won't get into here...

Sometimes using German torque specs (gudentight, not fukentight) can save a ton of headaches as far as broken studs and bolts. If you've turned enough wrenches, you can develop a feel for bolt stretch that tells you when it's gudentight. I use that in places where torque isn't absolutely critical.

Thanks for the input fellas!

Since I will be using the copper clad nuts, I wont be using any anti-seize. I will use the "grudentught" technique, and will re-check them after a couple of weeks.