One of my 4 bolts flew off on the freeway yesterday. Obviously this is a common problem but after researching it a little further I realized maybe the actual material of the metal itself (bolt) could be a possible culprit. Where the threads are only on the 304 stainless manifold and not on the turbine housing it got me thinking maybe if I used a 316 ss bolt or an inconel/Monel bolt this might prevent the threads backing out over an ordinary ss bolt. Are 12.9 bolts that you find at the Hardware store simply less likely to break or stretch? I wasn't sure the difference from say a 316 ss bolt and a 12.9 grade bolt. Anyone know?

Stage 8 people seem to like but I was wondering if I could pick up something from the local hardware store that would be easier. Maybe get longer bolts and put a nut with a lock washer on the end? However the main bolt would still find it's way out even if the nut was secure.

Not sure I want to tack weld the bolts on.... Watch me weld on the bolts and 10 minutes later need to take the manifold off for some reason. Lol.

I called ARP and the guy said not to use any metal gasket in between the two surfaces, it may contribute to the bolts backing out. Instead he recommended a high temp silicone sealer in between the surfaces, I asked about just plain Honda bond... He wasn't too familiar with that but said any high temp silicone sealer is by far better than a gasket.

More curious about the actual metal properties when threading into 304 stainless than anything.

Another theory is those castle nuts with cotter pins.

 

Mase uses carbon steel flanges not stainless.

304 is a type of metal where 12.9 is standard refereeing to the bolts tensile strength among other things.

12.9 is a Metric Standard the manifold bolts are Standard (http://www.americanfastener.com/tech...ings_steel.asp)
(http://euler9.tripod.com/bolt-database/22.html)

For a quick solution on mine I ran down to the store and found some 3/16" grade 8 shoulder bolts and used a lock washer on each. I have about 1000 miles and no issues so far.

My preferred method is to use hardened studs and retain the turbo with a serrated flange nut with safety wire.

You can use a longer shoulder bolts and put a C-nut or lock nut on the back side of the manifold flange.

Don't tack weld them, that is why they make safety wire.

No Stainless, stick with Moly or carbon steel.

As for the gasket if you can findanything that can with stand 1600F+ degrees I would be surprised. The gasket that is used is typical and with the correct hardware will not have problems.

 

So the term shoulder bolt is referring too just an ordinary bolt head. where as the gold bolts that came on the kit are called something else?

Thanks for clearing up my 12.9 confusion. So because of the thread pitch in the manifold... no 12.9's can be used correct?

 

Shoulder bolts have an integrated washer also known as Flanged Head.

http://www.mcmaster.com/#cap-screws/=85drya

Yes 12.9 is a metric thread standard so you will go by SAE standards when choising a bolt for your manifold.

Grade 12.9 Metric is approximatly equivilent to Grade SAE 8.8 Standard.

 

Just get the stage 8's.
Although, the tack welds are not hard to cut off. I had to remove mine once, took 5 mins with a dremel.