manifolds headers

hi i have a set of new headers to fit to the 996 but after having a quick look my nuts look pretty rusty so just wanted to see if anyone had experienced this problem and the likley out come ie snapped studs or stripped threads any tipps or advice welcome also i am trying to put a photo on bare with me

Nice lift! I have no personal experience, but I have heard lots of cases of snapped studs when undoing the manifold nuts. Not sure what the answer is either, but if you have a go, be aware it can happen, so be careful.

go into the job armed with thread remover tool: http://homerepair.about.com/od/interiorhomerepair/ss/screw_extractor.htm no getting away from it, at least two or more will shear.

I have now done this job on a 996 C2 and a 996 GT3. Resign yourself to a long methodical process as you will need to do this very carefully and you cant afford to damage the cylinder heads. The job should be tackled in stages and it is worth buying some good quality tools to start with. Access to a good heat source such as Mapp gas or Oxy/accetaline set will also be a bonus. A Dremel or similar multi-tool with wafer thin cutting discs will be very useful along with 115mm angle grinder. And lastly a very good quality stud extractor will be your friend!(Sealey Drill Chuck Type worked best for me) Don't under any circumstances try to use "easy out" reverse tap stud extractors because when they snap you will only be able to remove them by spark erosion - (way beyond DIY) 1. Bolts with a recogniseable head should be treated as a bonus because it may be possible to hammer on the next size smaller socket. It is best to use 6 sided Cro Mo impact wrench sockets as are less likely to remove the edges of the bolts. 2. If they wont shift with a socket and lever, heat them, then try to move them with an air or battery impact wrench. Heat them several times and repeat the cycle. If this fails the heads will probably round off or snap. 3. On Cat to Manifold bolts it may be possible to use a hacksaw and or Dremel and or angle grinder to cut off the nuts. 4. On the clamps that hold the Cat to Exhaust Boxes and Tail Pipes simply cut all the bolts off and lever open the clamps. 5. The most difficult part starts when the manifold bolts that are left, after trying all above, have nothing left to grip them by. The corrosion between the manifold and what remains of the bolt head means that the two are virtually fused together so the bolt head will have to be ground off using the angle grinder and/or dremel with mini cutting discs. 6. When all of the bolts or heads have been removed then it will be possible to separate the mainfold from the cylinder heads. In some cases it will be possible to grip the 5 - 10 mm of stud now sticking out from the head with your high quality stud extractor. 7. When this fails and all that is left is a piece bolt stuck in the head, the method of last recourse is to centre punch the stud and drill a small pilot hole thro the centre, taking great care not go too far and drill a hole into the waterway of the cylider head!!! To ensure the the hole is central AND at the right angle I re-attached the manifold and used it as a drill guide. Increase the size of the drill until you can just see the thread of the bolt. With a sharp spike it should now be possible to "implode" the bolt on itself and remove it. 8. If this fails, the thread in the head will have to be drilled out over size and a Helicoil fitted (a bit beyond DIY) When you have gone through the pain of removing all of the rusted bolts treat yourself to a beer and new Stainless Steel fixings for the whole system using plenty of coppaslip assembly compound. Link to Stainless supplier http://www.a2stainless.co.uk/ Of course, if this all sounds too much like hard work, take it to your local OPC or Indy and pay them to do it!

wow it sounds like you had a great time but its a plus that you did it twice or you love a challenge i will take your advice and aquire a oxy accet rig and various extracion systems before tackling it would have made sense to use stainless from new or would that be to easy it sounds like a pig of a job and if i wasnt keeping the car i would not bother i would be interested to hear from anyone who has paid to have this job done to see how many hours labour were charged thanks for your replys peter

Great write-up Chris. The (stainless!) nuts on my turbo to manifold joints were bearly recognisable as nuts when I got mine. There was so little of them left, my Indy was able to split them with a chisel, and peel the nuts off the threads of the studs. Slightly different scenario than yours, but I was amazed at how the stainless had evaporated.

im surprised at that, i thought stainless would weather better (pun intended). it would be nice to have a stainless steel exhaust and stainless nuts/bolts from new but im sure cost is the main reason they dont. mild steel is far cheaper.

Just to clarify - The factory fitted bolts on the 996 exhaust system are not stainless steel. (Thankfully, as they would even more difficult to cut, grind and drill!) The whole exhaust system is manufactured in a low grade stainless which does tend to rust to some degree but nothing like a mild steel system would. New replacement bolts now sold by Porsche may be less prone to rust than the originals but are still not A2 or A4 stainless. When re-assembling a system with stainless fasteners the use of coppaslip will aid future removal as stainless tends to bind on itself after several heat cycles. (but nothing like mild steel after it has rusted into a crusted blob!)

Not really too surprising, when it has to contend with this:

Quite literally red hot then. I didnt realise how hot manifolds/exhausts got.