Turbo maifold bolts keep coming loose!
 

How do I stop this? Any special tricks? I tried locktight, but even that only lasted a couple weeks. Its the bolts between the turbo and the manifold to be exact

try these

You could also try re-torquing once they have heated up

wouldnt that risk just stretching the studs or potentially breaking them?

Possibly, But maybe they aren't being torqued high enough in the first place?

Sometimes, when I have seen exhaust manifolds loosen bolts, they easy fix is to warm them up and 'snug' them up. (usually its only 1/8 of a turn or so)

I don't usually break stuff, well there was this one time....(6mm thread and 1/2" double impact)

everything I read and been told you are to re-torque exhaust bolt after they warm up before the cool down. On the Talon after swapping the turbo, I had to left the turbo warm up and then re-torque the turbo bolts and one had room to go.

good tip!

These things are great....They held my rear tire in place on my fixed gear bike, nothing else would work.

Can you get them anywhere else besides FM and in different sizes? I need 3/8"

just search for Serrated Flange Nuts or Serrated Washers

Yeah, this am while I was sobbering up.. I remembered the days before torque-to-yield bolts and everything including headgaskets need to be re-torqued after 500 miles. Almost every cast iron manifold need to be re-torqued when warmed up as well.

You can get them directly from NORD-LOCK.Just google it.

Home depot?
Fastenal?

Or we can always special order them,
Stephanie

About to buy hardware for my build and remebered there are issues with this.

Anyway, these puppies are also available from mcmaster-carr, 10 bucks for a pack of 5 pairs in 5/16.


Real reason I'm bumping this thread, I hear that its good to use stainless hardware. As an engineer/scientific type I started checking material properties and it look like steel is stronger AND has a lower CTE, but I know the nickel content in stainless will help it retain strength in high heat.

So, what has been the empirical data from you guys on this? Plain steel re-torqued when heated or stainless re-torqued when heated? I know all you super serious guys go for v-band setups and inconel housing bolts, its too expensive for my wallet and unnecessary for my skill level at the moment.

You buy the TSE Inco bolt kit. Yes, it's a lot of money; no, you never have to touch them again.

You and others on the board have done GREAT work on this issue, I'm not trying to dog that. The thread on your CHRA bolts (https://www.miataturbo.net/general-miata-chat-9/chra-turbine-bolts-relaxing-55717/) is fantastic.

Inconel just isnt in the budget right now, and I dont really track this car, just autox and mountain carving once a year. I dont think I'm serious enough for inco yet.
-Brad

I got a bag of 12pr on ebay for $6 shipped. I tried everywhere locally, both national and independent retailers, and could not come up with any without spending >$1 per pair which I thought was a joke. And nobody had them in stock...all special order.

For anyone in the San Diego area, you can grab the nordlocks at Marshall's Hardware on Miramar Rd.

All I can say is that I have FMs newer manifold (the older design allows the studs come intodirect contact with exhaust gasses...new one does not) and had them tap it out and install 10mm studs. With several track days and about 2 seasons of autoX on them, they have never flinched. With the older stuff on 8mm studs even street driving caused stub problems. Come to think of it, I should ask FM what studs they installed i nthe manifold.

I think the Stainless Steel 308(??) type studs are a sol'n that's halfway effective between ordinary studs and the $$ Inconel studs.
They're the same material used on boilers - there's an ASME standard alloy for them, and yes they have better high temp creep and CTE characteristics than the ordinary studs.

My turbo-manifold 10mm bolts broke when I was 4-hours from home. They broke when I wasn't at the track, just cruising. I know it's not cheap, but it's probably the same price as a tow home.

I must have a good manifold design, or magic bolts. 8mm, ACE hardware $.60 SS allen bolts, they all stay fairly tight. I replace them every couple track days, but that's more preventative than anything. My turbo sits on top of the manifold though, horrible for heat shielding, down pipe flow, down pipe routing, and looks, but apparently easy on bolts.

You almost have me sold, but part of the issue is the top set are through holes. To upsize to 10mm I'd likely have to do some fairly heavy dremeling as well.

Thanks for the info

Thanks for the info. Looking at 8-18 stuff from mcmaster right now.

some data, plan steel is not on here, but the curve is likly similar to the high alloy just shifted down in the y-axis.

https://www.miataturbo.net/attachmen...1&d=1310409885

I believe "we" tried that metal at the advice of TiAL on the CHRA and it did not work.

I believe one of the euro track guys had good luck by having the nuts welded to the manifold. I believe he (Doppelganger?) made some pretty informative posts on what he did and how well it worked. I'm too lazy to search for you but the info should be out there. Seems cheaper than inconel parts...

I bought 8-18 stainless with those nordlock things from mcmaster. I'll re-torque when hot and see how it goes.

Inconel safety wire works like this and allows for disassembly afterwards. My bolts are drilled and safety wired.

316 SS is better than 304 SS, but looks like 304 is still better than ordinary stud material.

Here's my posts with info:

https://www.miataturbo.net/showpost....&postcount=691

https://www.miataturbo.net/showpost....&postcount=729

https://www.miataturbo.net/showpost....&postcount=692
(both 304 and 316 are used for hi temp fasteners, aka "B8" and "B8M")

cool, thanks for the info. I also found out the 8-18 stainless is more or less 304 for our purposes; 304 has a few other metals that help corrosion resistance.

It definitely wasn't Doppelganger....can't remember what the guys SN is.