Stripping out exhaust studs

[94nonturboGS]

I've got an issue, when i was installing my exhaust mani I would be attempting to tourque the nuts down to spec ~20ftlbs. Well the stud would start spinning before i could even get close and i had one strip out the threads on the head. So I tried it on another one to see if it was just an issue with that one stud, nope it stripped out too, so i took out all of the studs except the 2 on the end and retapped threads into the remaining open spots in the head. I installed bolts into them to hold the mani and some of the bolts still stripped out, there are only about 6 or 7 i would say that are even close to being tight, one of them again stripped out. What can I do to keep the bolts from stripping out the threads in the head, i've never had this happen to me before, thanks in advance

 

[TurboJimbo]

Heilcoli

 

[ilco187]

as long as i have ever owned a dsm i have never torqued my exhaust manifold down, i always snug the bolts down and give a half turn, ive never had leaks, maybe try less than 18lbs

 

[954TalonTsi]

I had this happen when i took my old manifold off to do the rebuild. I just retapped them and put some locktite on them, gave them a day and i was able to tighten then down properly. If that dont work try a little bit of JB Weld Stik on the ends and shove them in there. I havent had any problem since i did my first technique,

 

[AWD_FIEND]

DONT USE JB WELD OR LOCTITE!!! There may come a time sooner than you think that you'll need to service the studs (if they break or rust fatigue) and you will have to undergo extensive repair to remove them. Once the threads strip there is a very slim chance that simply retapping them will cure your ills, but if you're like the rest of us unlucky people, a retap wont be enough. Use heli-coils as the steel inserts offer a stronger method of fasteing steel hardware into aluminum alloys (metalurgic incompatibility). You wont have another problem with torqueing your manifold to spec ever again.

 

[94nonturboGS]

thanks for the help guys! Looks like i'll have to use helicoils

 

[fwdmaster]

Helicoil those threads and get SS stud kit

 

[92blutalon]

15lbs? ok

 

[knochgoon24]

Helicoil those threads and get SS stud kit

+1 The SS studs are nice because they don't rust. I have 3 stud holes repaired with Helicoils. They're all holding fine.

 

[John Roberts]

Done with this one? Well, you really need to remove the Exhaust Stud from each of the ports properly..Or sometimes you might really need to remove with force.

 

[94nonturboGS]

kind of, I got most of them to hold in there, except one, it's semi tight so I was just going to see if I had any exhaust leaks if/when I get it running

 

[98mitsubishigst]

helicoils if a must,

i tighten mine snug, i never torque them down to factory.

 

[94nonturboGS]

Have an exhaust leak now, so looks like i'm taking them out and helicoiling the head

 

[AWD_FIEND]

Bad luck, but cant say we didnt warn you. Check out the videos on youtube about Helicoil/keenserts they're very helpful.

 

[pboglio]

I don't like stainless bolts for ANYTHING. They gall everything they come in contact with. Make sure the exhaust manifold is machined, filed, or surface ground flat within .005" at least. Then go ahead and helicoil the head and you should be O.K.

 

[94nonturboGS]

Not a big deal, just adds to the list of things to do though haha

 

[AWD_FIEND]

I don't like stainless bolts for ANYTHING. They gall everything they come in contact with. Make sure the exhaust manifold is machined, filed, or surface ground flat within .005" at least. Then go ahead and helicoil the head and you should be O.K.

They gall everything they come in contact with, what are you talking about? Stainless steel makes outstanding fastners and many car builders have been using that material for decades, myself included. But you need to be aware that when threading any steel fastner into aluminum it presents the opportunity for a unique form of oxidation causing the threads to bond. This is usually not a problem unless extreme heat is involved in which case the use of anti-seize is required. But in this case heli-coils are steel and therefor a stainless or hardened steel fastner wont cause an issue. The use of stainless for exhaust fastners is particularly wise because its high carbon content makes it less prone to heat stress and failure. If you have a lot of trouble with stainless fastners consider the application you're using them in and take the necessary precautions (ie thread threatments) to avoid issue.

 

[92AWDHX40]

I didnt know that they didnt rust i busted two this month, maybe ill be looking into some.

 

[AWD_FIEND]

Stainless steel is extremely rust resistent, but it's not infallible. Whenever using steel hardware for exhaust manifolds on aluminum heads you should always use anti-seize (copper). If you heli-coil every thread, however, it's not necessary to use anti-sieze, but in extreme winter environments I would still use it.

 

[pboglio]

They gall everything they come in contact with, what are you talking about? Stainless steel makes outstanding fastners and many car builders have been using that material for decades, myself included. But you need to be aware that when threading any steel fastner into aluminum it presents the opportunity for a unique form of oxidation causing the threads to bond. This is usually not a problem unless extreme heat is involved in which case the use of anti-seize is required. But in this case heli-coils are steel and therefor a stainless or hardened steel fastner wont cause an issue. The use of stainless for exhaust fastners is particularly wise because its high carbon content makes it less prone to heat stress and failure. If you have a lot of trouble with stainless fastners consider the application you're using them in and take the necessary precautions (ie thread threatments) to avoid issue.

The phenomenon exists, trust me on that one. I have a very bad memory of the stainless "contact pressure welding" problem from my design project at work, never again am I using stainless with something that could side load the fastener even a minute amount. Yes you could use antiseize which would be mandatory on stainless, but in the situation I had it was an NSF food safety issue to use lubricants and stainless fasteners were preferred. Complicated issue in any case.

You don't NEED a stainless stud in this location if the proper torque setting on the copper nut is used. Its the manifold warping that pulls the stud out of the head or snaps it. If the stainless stud snaps clean flush with the head, then you truely are ####ed without a "carbide" drill bit, the expensive ones that cost $10. That'll find the next weak link which is the helicoil in the aluminum head if your lucky. Wrong way to solve a problem IMHO. Fix the problem at the source by resurfacing the manifold flat every time you pull it for whatever reason. Thats my 2 cents.

 

[inneed4dsm]

i bought the SS exhaust manifold stud set from dsmparts.com definetly the best investment ive ever made to my car

 

[AWD_FIEND]

The phenomenon exists, trust me on that one. I have a very bad memory of the stainless "contact pressure welding" problem from my design project at work, never again am I using stainless with something that could side load the fastener even a minute amount. Yes you could use antiseize which would be mandatory on stainless, but in the situation I had it was an NSF food safety issue to use lubricants and stainless fasteners were preferred. Complicated issue in any case.

The phenomenon does exist, you're right about that. But pressure welding isnt common enought to disregard the positive properties of stainless in automotive applications, even those that see extreme side and thread loads. Plus it occurs as commonly with all steel fastners not just stainless, including mild, hardened, zinc, oxide, and nickel. I'd have to say in your situation there is likely some other design flaw that is contributing to fastner bind greater than material composition of the hardware. I can appreciate you're advising based on your experience and you bring up an important point regarding the proper application and preperation of stainless hardware, but in the automotive environment health concerns dont restrict the use of very important thread treatments. In the end for all those concerned, feel free to continue to use stainless in any application you deem fit in order to take advantage of its visually appealing as well as it metalurgic benifits. But keep in mind anti-seize should be used when threaded into dissimilar materials where high heat or high fastner torque is expected.