JasonC SBB

Drill and tap the turbine inlet, not the manifold. That's what I did, after my AVO cast mani cracked through the EGT hole after 7 years.

dgmorr

iTrader: (4)

Where did you guys order the M6 inconel bolts from?

JasonC SBB

What's the difference between Inconel and Nimonic, and why does hustler think Inconel will solve his problems?

How do their CTE's compare? Tensile strength at low and high temps?

TurboTim

iTrader: (9)

My thoughts exactly.

fooger03

iTrader: (2)

Because Inconel has proven to solve this same problem (bolts stretching/relaxing due to high heat) at the manifold -> turbine housing joint

So we use inconel bolts because they do not "soften" or stretch the way stainless steel does (though we expect they expand and contract like any good bit of matter will under heat - they simply do so much more favorably than the SS or other metals do)

And we use safety wire to keep the good bolts from vibrating loose. Even though the inconel has a much more favorable heat propery, the heating/cooling of the turbine housing will occasionally cause the inconel bolts to become "free floating" in the housing (where once they were torqued, now they are not even "finger tight" simply because of the heat cycling/expansion between the bolt/housing) The safety wire simply keeps the bolts from loosening when this state is achieved.

SS bolts w/o safety wire --> bolts stretch and/or loosen
SS bolts w/safety wire --> bolts stretch
Inconel bolts w/o safety wire --> bolts loosen
Inconel bolts w/safety wire --> tight like a tiger

TurboTim

iTrader: (9)

WTF is Nimonic? I assumed it was tial's fancy marketing people creating a word that sounded unique.

Drill/tap it where? There's nothing thick. No flange remember...vbands. He could send it to his fabricator and get it for the cost of material & shipping cause his fabricator likes him.

TiAL. They now come standard when you buy a turbo with their turbine housing too. They've made a few different styles the first of which did come predrilled for safety wire. I've taken a sample of each and ran 'em thru Jesel's SEM/EDS xray detector gizmo to get the alloy content, results posted in this thread. 30Rc.

I could google "nimonic" to see if it exists or if it's a buzzword. If it doesn't exist then using it will just further confuse people. If it does exist then someone would have to make the bolt.

With me spending so much time in the prototype dept drilling fuckign holes snapping drill bits quite a few people asked why don't we just do the entire bolt in one of the mori seikis. ha. Never happen.

JasonC SBB

But Nimonic is also a very high heat resistant alloy for making bolts with. And Hustler's Nimonic bolts backed out (albeit without safetywire).

Inconel has the disadvantage of being very difficult to machine.

JasonC SBB

NIMONIC bolt experiment used NO SAFETY WIRE.

Nimonic is a trade name registered by the same company that invented Inconel.

I think both are used for bolts inside jet engine turbines.

TurboTim

iTrader: (9)

ahh thanks. I was gonna google it but I figured you'd do that for us.

Doppelgänger

iTrader: (12)

Hey Hussie...here is some food for thought-

OK..big words, right? Well I remember the 'epic studs' thead and the discussion that on a lot of the manifolds (BEGI and FM) that the turbo-to-manifold studs were exposed to the raw exhaust gases causing the difference in material to prematurely get much hotter/expand at a different rate than the turbine housing whereas most others and OEM turbo cars do not have studs/bolts that are in contact with raw exhaust gases. Pretty sound theory if you ask me..though I am no M.E.
Anyway.
I just replaced my GT28 exhaust hausing and clearly remember that when I pulled the 8 housing bolts off, the tips were black with carbon. I just ran out into the garage and looked at the housing and the 8 bolt holes all go through to the inside where the bolts would be in direct contact with the superheated exhaust gases.

Soooooo.....maybe finding a way to shield the bolts from direct exposure? Yes? No?


Or you already knew this and it was mentioned somewhere between pages 5 and 9 that I didn't read carefully.

TurboTim

iTrader: (9)

**** now there's 8 bolts?! damnit.

Hey hustler, try making a cool looking crane with heim joints to the turbine housing. That'd fix it. Full circle time again baby let's keep this thread rollin!

TurboTim

iTrader: (9)

Damnit Jason you got me going now. http://en.wikipedia.org/wiki/Nimonic

I'm still naming my first born Nimonic.

Doppelgänger

iTrader: (12)

Oooops..6....it's SIX dammit....6. I wasn't paying attention to what finger I was using when I typed that.

TurboTim

iTrader: (9)

Maybe he should drill for 8 holes then.

Doppelgänger

iTrader: (12)

What about drilling/tapping a new set of holes that don't go all the way through? Maybe that + inconel bolts? I'm typing on a whim and haven't thought about the downside or problems with doing so.

hustler

iTrader: (6)

Drunk?
What about "Moon Unit"?
It's 6, yes they see exhaust.
I will.

TurboTim

iTrader: (9)

How about drilling completely through the turbine housing and using through bolts.

Not any more :( I like moon unit

Doppelgänger

iTrader: (12)

Well hell, at least my idea is better than something Hyper would come up with. Hyper would probably try to drill all the way through.

kaisersoze

iTrader: (8)

Precision turbo's housing uses M8x1.5x16 hardware
no info if anyone has a similar problem

JasonC SBB

LOL is Moon Unit Zappa that famous?