Turbo maifold bolts keep coming loose!

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07-11-2011, 01:16 AM

#21

hustler

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Quote:

Originally Posted by golftdibrad

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

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.

07-11-2011, 01:36 AM

#22

curly

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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.

07-11-2011, 08:44 AM

#23

golftdibrad

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Quote:

Originally Posted by hustler

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.

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.

Quote:

Originally Posted by curly

Thanks for the info

Quote:

Originally Posted by JasonC SBB

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.

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

07-11-2011, 02:45 PM

#24

golftdibrad

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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.

Attached Thumbnails

Turbo maifold bolts keep coming loose!-temp-curve.jpg

07-11-2011, 03:02 PM

#25

hustler

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

07-11-2011, 03:18 PM

#26

Efini~FC3S

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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...

07-11-2011, 03:51 PM

#27

golftdibrad

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

07-11-2011, 04:20 PM

#28

hornetball

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Quote:

Originally Posted by Efini~FC3S

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

07-11-2011, 05:52 PM

#29

JasonC SBB

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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")

07-11-2011, 06:25 PM

#30

golftdibrad

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Quote:

Originally Posted by JasonC SBB

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.