stage 8 header bolts

homewrecker

homewrecker

gear jammer
Joined
Oct 23, 2007
Messages
2,137
Anyone ever used them on a cummins. They have a 12pt or 6pt set specifically for the 5.9. Had issues with my last set of stainless hex heads loosening after a few hundred miles. Looking for something that will stay torqued and not rust.
 
homewrecker said:
Have done that already. Had a few break.
Been digging on the internet. Seems a combination on nickel based anti seized and high temp rtv holds stainless fasteners very well. May give this a try.

Sent from Razr Maxx
Click to expand...

What Grade stud did you used and what are you hanging tripples.I have had my twins on mine for 3 years and not had one problem.My setup has no support brackets either all on the mainfold. my studs was 12.9 grade
 
I have been using stainless steel studs (5MM sunk allen head ends) and stainless steel flange nuts on my truck for over a year

These studs have a 40,000 PSI tensile, so they are more than strong enough, especially for how many there are on the exhaust manifold

I checked the nuts once since the studs were installed and have never had an issue with them loosening

I only used blue Loctite on the threaded portion of the studs that go into the head
 
No matter how tough the studs or bolts are, if the manifolds holes are just large enough to fit over the studs, (especially the farther away from the center of manifold you get) the fasteners in a bind will shear off after a few heat cycles almost every time sure to heat expansion and contraction.
More so in solid one piece flanges.
 
thats why the steeds are nice, they give a little room to grow.

I'm using the 15mm nuts from the 4 turbo flange nuts, bought 12 of them cause they are nice stainless flange nuts, with regualar grade 8 studs, tq'ed to just the cummins manifold TQ spec, over tourquing them is probably why they are breaking for you
 
triton said:
been looking for SS studs myself but, haven't found them yet. I used these myself for a while with no issue...

http://www.jegs.com/i/ARP/070/772-1004/10002/-1
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I saw those while searching. Been reading on ways to keep stainless fasteners tight. Didnt want to use locktite. Been reading on some of the gasser forums and the rtv and nickel antiseize keeps coming up for keeping header bolts tight. Or use an extra thick heat treated stainless lock washer.

Sent from Razr Maxx
 
^^^ Yep!

Loctite is nothing more than sugar water....and on anything that hot will just return back to liquid stage. High temp anti seeze and locking nuts.
 
mitsubishi turbo cars (eclpise, evo) use a conical locking washer, two of them stacked, facing apart from each other <> like so will keep anything together, and are designed for some serious heat, where normal lock washers fail. i believe they are a 10mm diameter bolt as well.
 
I never understand how they can come loose. I put anti seize on my bolts to make them easier to remove. IIRC torque spec is 35 ft lbs
 
crackerman said:
mitsubishi turbo cars (eclpise, evo) use a conical locking washer, two of them stacked, facing apart from each other <> like so will keep anything together, and are designed for some serious heat, where normal lock washers fail. i believe they are a 10mm diameter bolt as well.
Click to expand...
Will have to try and find some info on those washers.

WUnderwood said:
I never understand how they can come loose. I put anti seize on my bolts to make them easier to remove. IIRC torque spec is 35 ft lbs
Click to expand...
I dont know how but every couple hundred miles the stainless bolts were loose. Only used antiseize and lock washers. Never had an issue with the factory bolts or regular grade8 bolts.
 
I forgot to add that I am using lock nuts as well. I am hanging twins off my Stainless Diesel manifold with no bracing.
 
D45 said:
I have been using stainless steel studs (5MM sunk allen head ends) and stainless steel flange nuts on my truck for over a year

These studs have a 40,000 PSI tensile, so they are more than strong enough, especially for how many there are on the exhaust manifold

I checked the nuts once since the studs were installed and have never had an issue with them loosening

I only used blue Loctite on the threaded portion of the studs that go into the head
Click to expand...

For comparison sake, a run of the mill grade 5 bolts, or 8.8 metric screw, is 120k psi. 3 times what you listed. Grade 8 or 12.9 is 150k psi.

crackerman said:
mitsubishi turbo cars (eclpise, evo) use a conical locking washer, two of them stacked, facing apart from each other <> like so will keep anything together, and are designed for some serious heat, where normal lock washers fail. i believe they are a 10mm diameter bolt as well.
Click to expand...

Belleville washers are what you are talking about. We use them on gland followers for higher pressure steam packings.

Belleville Washers
 
I double checked and the specs on my stainless steel studs are 80,000 PSI

I am also using serrated style flange nuts, also in stainless steel
 
I am running stainless socket head cap screws on mine with standard lock washers they have been on there a couple of years and don't seem to be coming loose.
 
When we use a nickle anti-seize when ever we deal with stainless threads in our piping applications at work.
 
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