Header bolts siezed ... also anyone recommend an exhaust

Two issue here. My 1998 C2 needs a new exhaust its corroded and blowing and all the fitting/bolts etc are rotten with rust. Eventually I managed to remove the bumper and heat shields off again all the bolts rotten. i thought it was just the back boxes but the headers are also rotten... the bad news is that the bolts on the headers to cyclinder head are shot to the point that the heads dont even take a socket ... also the dude who owned the car before me must have had a go and two bolts are headless and snapped off in the head. anyone got any advise... can the holes be repaired with helicoils engine insitu? anyone done this repair engine insitu... the sad thing is that the right side header bolts are all ok and loose but the right side are all shot every one has no workable head. unable to even attempt to remove them as i cannot get a spanner or socket on short of hammering an under size socket also two have already been snapped off by others in the past. c: Any help would be grateful ... no jockeys please.. :cop: Also can anyone recommend a sensible priced set of headers and boxes .. is the ps mod better than sports boxes or would you put OE back on it. :thumbs: ps limited budget ... also i note on usa ebay some cheap ss headers are they any good anyone fitted one... note all the adverts say 996 year 99 onward... cannot see that the headers on a 98 car are different to a 99 car ... anyone know of any difference as dont want to order the headers and find that they dont fit. thanks pipton 996 rusty carrera boy... PS my 996 is otherwise mint the rust was caused through using the car in the winter.. luckily everything else spot on...

I recently bought these on ebay for my upcoming turbo exhaust installation.:- http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=180511078975&ssPageName=STRK:MEWAX:IT

This is a common problem with Boxsters and 996's but beware - trying to drill out the hard stud in a soft alloy head is likely to lead to missalignment and dissaster (if you E-mail me directly I will send a photo of what can happen from a car drilled out by another garage). We manufactured a hardened drill jig that can be fitted under the engine to allow drilling out in line and helicoiling. When we strip and rebuild engines - there are usually several botls that are similarly seized in so much they have to be jig drilled and helicoiled - it seems Porsche were unable or unwilling to coat the bolts in anything to help prevent the problem. Good luck, Baz

Hi I have done this on my 993. I ended up Dremeling and snapping the nuts off. As long as you do not break the stud off flush with the head you are in with a chance. If you can get the nuts off by hammering a socket on then do it. Also use plenty of plus gas and heat. Also hit the nuts to shock them. Once the headers are off you will be left with some broken studs. Get a Lazer stud extractor from Halfords. The one that looks like a drill chuck. They are amazing. I used a 1/2 drive version but they are available in 3/8 and 1/4 I think. Heat the studs several times with a blowtorch, or if you have one get them really hot with an oxygen torch. I used a blowtorch and wished I had gone and bought the hotter version. I was left with two studs snapped off flush with the block. There is a jig that you can use to drill them in situ. I made my own from cutting down a perspex dowel guide from Axminster. It comes with steel drill guides and I bolted it to the exhust port. Although it worked, drilling the studs was a total nightmare. I do not even want to talk about it. Had it all gone horribly wrong you can helicoil. In any event you will probably need a tap to clean the threads with afterwards. I have however got some pictures of the process which I will dig out and post as soon as I get the chance. Try to make sure you give yourself every opportunity to get the studs out without breaking them off flush with the head. Act in haste repent at leisure on this one. Edit, for the 993 I replaced the 13mm nuts with 12mm copper coated steel ones. Easier to do up because much better access. Plus no future rust. People use them on Lotus Esprits. Best of luck Berni PS And if you do not like lying upside down with swarf and rust falling in your face do not even start the job.

That seems like a good alternative - but the problem is that many/most people find they have a problem when the bolt has snapped and therefore already flush with the head. Because the thread spirals around a central core of the bolt, although the broken piece in the head appears round - the centre of it is not the centre of the bolt - only the centre of the spiral - off set by the thread depth. What you see as a round piece of steel is not the diameter in line with the centre of the bolt and there is no way of telling if the bit you can see is off set in the right direction. To see what I mean - put a bolt in a vice with the thread sticking up and look at the end. One side of the first piece of thread is in line with the outside diameter and 180 degrees opposite the edge is in line with the root of the thread. It looks round if you file it flat because it is a round dimater that is gradually moving down the bolt as the thread rotates around it. So even if you managed to put a drill in the centre of the broken piece that you can see as a pilot hole and then tried to drill out the rest - your drill would still be off centre and would run away in the weakest side and end of a long way off centre and at an angle. This is the classic problem of people trying to drill out snapped bolts - doing their best to keep in line with what looks like the centre of the bolt - but actually isn't - so they have no chance to get it right. Furthermore the material that the heads are made of on the 996 is not as dense as the 993 heads and does not machine/drill/tap as well. If you are lucky enough to have a piece of the original bolt/stud sticking out still then the easiest way to drill out the bolt is to make a simple tool on a lathe which has a thread in it for a short distance and then a smaller hole. Alternatively weld a tube with a smaller hole in it on to a nut centrally. Screw the threaded part on to what is left sticking out and then drill through the centre of the smaller drill hole leaving a pilot hole right through the centre of the stud. Then cut/grind off the sticking out part flush and open it out with larger drills until you reach the helicoil drill size. If you are really stuck - using a long nut on whashers and using the centre to spot a drill of the tapping drill size may provide a centre drill type location to put a lipot hole in first. Get someone to help you keep the drill line true, and remember that when opening out an existing hole always run the drill much slower or it will burn the edges off the cutting face. Best of all of course is to do so many you have a proper hardened drill jig like us - but not justifyable for a home mechanic doing his own thing just once. Baz

more info Had already figured that the chances of me drilling a dense mild steel stud out of an alloy head was not possible with my shaky hand and a cordless, laid on my back... :floor: two studs are already snapped flush so drilling is unavoidable.. what a crazy design by porcshe to have such a simple thing creating a potential nightmare even an old ford wouldnt have this type of problem. :dont know: I can see the logic of dremmeling off the heads and using a stud extractor although only about 8mm of thread will project is that enough?. the bolt heads have welded themselves to the headers with rust you cannot seperate the two seem to have merged together. I understand the finding the centre of the stud issue with the spiral being off centre. Can you please send me some info on the drill.. my email is [email removed] :?: I have contacted a local engineers shop who can do it for me but my car would need collecting and bringing back and i think the bill will be 300+ at the shop so 400+ with the transport to solve this problem. :sad: Can you use stainless studs? :?: could do with someone to make a header plate pilot drilled only to the stud centres with some method of clamping it in place... Must admit I am bit confused by some of the ideas you have raised.. got a blow torch at the ready .. this is my plan... Buy a dremmel and dremmel off the bolt heads... that way i know that they will not snap off flush... and then use a stud extractor and blow torch... Good plan? Once the header is off i will be able to see if the stud projects on the two heads that are already missing Ihope but in reality I am almost sure that there flush. so i need a plan for this... not scared of helicoil or reaming out clean... very scared of drilling without proper gear... The joke is that i set about this work under no pressure to have my car on the road... and yes my other car a 2007 rexton then decides not to start had it in at the dealers today and they have less idea than me. Appear that I have had some dirty fuel thats fouled a diesel injector causing it not to close fully meaning that I am unable to get the desired fuel pressure on crank to start the engine... the joke is the ssangyong OBD cannot tell you which injector it is... so we have two cars both out of action so were in the works van like gypsys at the supermarket... the wife is so happy with me and thinks i should sell the Porsche... thats all you need when faced with rusted studs without that this exahaust job would be so easy and the porsche would be buzzing away like it always does... HELP!!!! Anyone got the kit who fancys earning some crinklies can come to my place and lather there face in swarf in the knowledge of a pocket of crinklies and a very happy customer... Need to attempt this at the weekend and have the beast BOTR Monday.. Phil PS great posts you both but the local ssangyong dealers to shame... thanks please help me take the right route... :thumb: The joke is i had chance of some great OE exhaust cheap and passed on them thinking about a milltek system now Id beg for them as i need the cash to solve the stud issue and get some headers... what a carry on... someone said it takes 2 hours to replace the exhaust system it has taken me 8 hours to remove the bumper and remove about half of the exhaust system due to rotten posi drive screw fixing and bolts. If you can do a complete exhaust overall on 2hrs you must have blue tight overalls with a red S on the front!!! :worship: I did my plugs in 3 hours so I am no yo yo

I am glad that you have brought up this issue because there are actually very few garages with the equipment to fix such a simple problem properly. Furthermore when a customer car comes in with say a blowing manifold gasket - they are often incredulous that we have to charge time to fit a jig and helicoil the bolt hole - although you now know that even a modest charge for that is better/cheaper and a better result probably than the time you are going to take to fix the roblem. Because we have our own precision machine shop in which we manufacture all sorts of engine and suspension parts - it is relatively easy for us to deal with such issues professionally. Previously we have (for example) received a 944 having had a water pump fitted from a well know relatively local independent specialist with three broken bolts stuck back into the pump with glue and a lot of silicon sealant around the sealing face. OK it was working but years before we bought a right angle drill and made another drill jig to line up the holes for that model so we could fix this common problem properly - but were a little shocked at what some other respected dealers can get up to. What this throws up is that there are some dealers you can trust to do a proper job and others that cannot or will not - and it can be very difficult for the public to know who is who when they rarely find out and we do not indulge in criticising our competitors - who often get away with murder. Unfortunately it costs so much to do the jobs like this properly (special tools, equipment and time making things) that those that don't and bodge things up are often actually more profitable and can afford more glamorous advertising as a result and continue to thrive - which obviously is a fact of life that irritates all those who try and do things right - like us. Baz

Hi Here is a picture of the drill guide. You start with a smaller one and work your way up. Unfortunately these particular ones are sold in imperial sizes only. You can see the other snapped stud in the background. If you decide to do the job yourself there are some other tips I can give you that I learnt doing mine. Please let me know. All the best Berni

update on my progress The bolts heads were all shot... rang porsche for advice they said" WD 40 and hammer on the next socket size down" I dont think WD40 would do anything firstly it wouldnt get to the threads as it 20mm away from the head and bashing on a socket is not going to work when the bolts are shot. :hand: I bought a dremmel kit from the olf B&Q and have cut of the bolts heads and removed the mainfold. So i now have 4 clean studs stuck up 20mm proud, 1 snapped off by the last owner stud up proud by 10mm and one again snapped off by previous owner stud out approx 4mm and very raggy. I have heated the studs up in rota and sprayed WD on the root of the stud leaving them overnight covered in WD40. I went to halfords for a stud extractor web say's they had 2 in stock when i arrived they had non... maybe a good thing may have been tempted to rush best i take my time. I need two solutions to get the clean studs out 1 and to solve the two previously snapped off ones 2. That drill guide of Bernis look the answer had a look in my tool vault to see if i had anything that can screw onto the stud... I am hoping i can remove the 4 clean ones using heat and a stud extractor .. not the drill type but the chuck one that grabs the stud.. anyone used this type . I wouldnt want to snap the studs off flush with the stud extractor after spending all sunday on my back with the dremmel. I could do with a NUT that i can screw on the two smaller stud stumps that will centre my drill or something like Bernis drill centraliser ... shall trawl the web... i did se a drill centralising gadget on youtube will revisit that now i know what i am facing. Can i say that all the bolts on the entire exhaust system looked like the bolts you get at Brighton Pier rusted heavily and flaking.. I questioned porsche why the 12 cylinder head nuts were not stainless given the hassle and he had no idea other than the new 997 still has mild steel studs... crazy... £80k car and within 5/6 years its got major problems like this.. no wonder they dont hold the value.. A chap in my local has had a number of 911s and has gone full circle back to a 993 after two 996s and a 997... he says the 993 was the last car built as a true porsche after that the 996 was a car built for profit and had a shorter lifespan to make way for the 997.. not sure in the long term thats good for Porsche as a load of cheap porsches on the road due to bad resale figures due to issues like this wont do much for the new car prices.. I think porsche are making on now but for how long.. :?: My plummers blow torch isnt really the best or that hot could do with proper bottles I have seen posts about melting the alloy ... is this real or not... i think if the studs were hot enough i could work them ALL out one way on another.. ADVISE on this greatly appreciated... Hoping yes hoping to have the old girl back on the road... got a bit jealous sat in my local watching everyone passing by today in various machines including a nice yellow classic 911 with roll cage etc sounded great... Just wish i could wake up and all the suds were out so i can start bolting everything back on. Went for a SS haeder from the states and some MIltek boxes new bolts and fitting throughout should be mint and a massive improvement from my blowing noisy flaking exhaust. I have about rebuilt this car how anyone can afford a 996 who uses the local garage i dont know.. Had my other car in for a simple diesel injector and it £400 image tackling my exhaust Its taken me around 8 hours to remove the bumper and exhaust... before solving the stud and rebuilding i reckon my bill would be several thousands.. PHIL Still might be if i balls up! Phil

Hi Pipton, Interesting problem you have there. I think your strategy for dealing with this is good, especially cutting the heads off and leaving a good 20 mm of stud to work with. This is also good because in doing this you have removed the axeal force that was applied by the bolt head. This will actually have the effect of making the studs easier to turn because the axeal friction load is removed from the threads. My advice is to buy a good blow lamp (and also some plumbers freeze) Heat the studs and the surrounding casing and then using a hammer and a socket extension bar to apply shock loading to the stud to break/crack the corrosion bond between the casing and the stud. Add plenty of wd 40 and repeat a few times. Then heat again both stud and casing but this time quickly spray the freeze on the stud only to cool the stud and make it contract. Quickly place your stud extractor over the stud and (hopefully) break stud free from the corrosion bond. Try to be patient at this stage and apply plenty of wd 40, re tighten the stud a little followed by loosening ... and so on.... If this does not work, instead of starting with loosening the stud, try tightening a little to break the corrosion bond, then loosen as normal. Good luck and keep the updates coming.

BEEN OUT IN THE GARAGE TONIGHT AND HEATED AND WD40 ALL BOLTS ABOUT 5 TIMES IN ROTA .. HEATING APPLYING WD40 AND THEN MOVING TO THE NEXT. I CAN VISIBLY SEE TWO OF THE STUDS ABSORBING THE WD DOWN THE THREAD RATHER THAN IT FORMING A DROPLET ON THE END OF THE STUD SO GAINING IN CONFIDENCE ABOUT MY CHANCES. DONT UNDERSTAND HOW REMOVING THE HEAD MAKES THE STUD EASIER TO TURN I SUPPOSE YOU MEAN THAT I HAVE REDUCED THE SHEAR FORCE OF THE STUD STEM BY APPLYING THE TURNING FORCE DIRECTLY ONTO THE STUD SHAFT? :dont know: PLUMBERS FREEZE IS A GOOD IDEA I CAN SEE THE LOGIC OF BREAKING THE SEAL AND THE CONTRACTION PROVIDING THE MAX CLEARANCE WILL GET SOME TOMORROW... D DAY TMRW NIGHT GOING TO CRACK THE STUDS WHEN I GET BACK FROM WORK... I HAVE HEATED AND WD40 THEM ABOUT 10 TIMES EACH SOAKED IN WD FOR 48 HOURS SHORT OF THE PLUMBERS FREEZE AND A BLOW TORCH AND SOME LUCK CANNOT SEE WHAT ELSE I CAN DO. GOING TO USE THE ALLOY SPACER ON THE OLD HEADERS AS A TEMPLATE FOR THE TWO I AM GOING TO HAVE TO DRILL. ONE COMFORTING THOUGHT THE BOLTS ARE 28MM LONG AND ONLY ABOUT HALF OF THIS IS IN THE BLOCK SO SHOULDNT BE TOO BAD! :thumb:

Hi Pipton, An experiment you can try is to- Take a nut and bolt which are not corroded , place some washers between them and tighten them really tight together. Place nut in vice, try to turn bolt.... wont turn. Cut bolt head off and remove washers.... Bolt stem will now be easy to turn, even by hand I think you will have complete success tomorrow pipton, as above you will only have to turn to overcome corrosion rather than corrosion AND a tight bolt. Don't forget to place a bar on the stud ends and tap with a hammer to break the corrosion.

Hi There The Lazer extractor that looks like a drill chuck (see link below) http://www.screwfix.com/prods/55057/Van-Car-Accessories/Mechanics-Tools/Laser-Impact-Stud-Extractor This gripped one broken stud that had only a few mm sticking out. I really did think that I would be drilling that one as well. I think plus gas is better than WD40, but I have no real evidence to back it up apart from personal preference in use. When shocking the studs I also hit them (gently) from the side using a light hammer. I also think copper coated steel nuts are superior to stainless. You can also get phospour bronze but I could not find anyone who could supply a low number. I hope that they all come out. Fingers crossed for you. Berni

:sad: Sods law... first three came out a breeze actually the threads were very clean with no sign of corrosion INSIDE THE STEM... came to the fourth stud and yes it sheared. Looking at the stud it had a fault you can see staining in the steel cross section at the break not clean like the others So i am now have 50% less of a problem then when i started three holes are now clean and perfect... I used the laser stud extractor good piece of kit but a little big in the body.. I think i maybe wasnt square enough on the stud that I broke off the body of the laser tool was rubbing the engine casing along side the hole.. So I am now faced with drilling I have established that 20mm of the stud is in the casing so no big deal i dont think :dont know: . The problem is the studs are so hard the pilot dril bit I am using 3mm isnt touching it... I have blunted 3 to get about 5 mm down the length of one stud tried fast drilling, slow drilling and lubricating with oil. Any suggestions... My plan is to drill out as big as i can WITHOUT intefering with the thread... so Its an 8mm stud so probably go to a 5mmm drill bit max... This will leave effectively a threaded tube inside the hole... using heat and a stud extractor I am hoping that given the stud will become a tube the expansion and contraction caused by the blow torch and given that the heat will be more direct [blowing up the tube] and the stud will have more scope to move this might be the solution for the last three... I am spending time to avoid helicoling this is my last option. One thing thats positive is the condition of the thread in the three holes that i have suceeded to remove. If the remaining three are as clean the thread as the others i have a genuine chance of getting all 6 holes back to standard ...which would be great.... :thumbs: I need a better solution for the drilling... Cutting compound? any ideas I bought top bosch drill bits all the shagged in less than 10mins on 5mm drilled... I also avoided overheating the drill tip and tried oil lubrication... If can sort the drilling I have a real chance of having my car back for next week... PLEASE PLEASE I have been driving a transit van with no aircon it does 60 / 65mph its taking me forever just to do short trips... so hot and so slow... Alothough i will need to recahrge my aircon system!!!! STARING A NEW POST OIN THIS AS ITS A MUST BEFORE I BRING IT BACK INTO SERVICE... PHIL

Re: update on my progress Don't be tempted to use Stainless Steel Studs, The Mild Steel Studs used are ductile, which they need to be given what they have to withstand. Buy the proper Studs from Porsche. If you would like to spend more money on the studs, get them nickel plated instead. I dont think St.Steel likes getting hot and cold to often, that blue effect you get when you heat St.Steel is a thick oxide layer, with a depleted chrominium layer under neath, which doesn't help. Seem to remember something about chrome becoming chrome carbide at grain boundaries, hence the depletion. (It was 12 years ago!!! waiting for all the material scientists to shoot me down now :wink: ) 1 question I've thought off....are the bottom of the stud holes close to the water jacket of the cylinder head (assumming the head has water flowing through it, never seen one off (yet)). If it is, does anyone now how close, just incase you get excited with the drill and spring a leak Any decent 1 man machine shop will knock up a jig for around £20-30 cash.. It's 20 mins work on some offcut and will provide tax free drinking money for the machinist involved. :bye: