Broken stud, with a broken torx bit
Discussion
HRG said:
Are you any good with a dot punch? You may be able to free it that way working from four quarters, but be careful with the softer parent metal if you try. The secret is knowing when you're beaten and not making a bad situation worse IMO.
Lol, beaten, probably. Stubborn, definately. I'll give that a shot though mate cheers.DaveL485 said:
Basically, broke off a stud flush with the alloy head.
Drilled it out to about 3mm down the middle.....thought i'd be cheeky and knock a T27 torx in there to try and wind it out. You can guess what happened.
Any suggestions or is spark erosion the only option?
You'd probably have been well advised to read my web site article on this topicDrilled it out to about 3mm down the middle.....thought i'd be cheeky and knock a T27 torx in there to try and wind it out. You can guess what happened.
Any suggestions or is spark erosion the only option?
http://www.pumaracing.co.uk/ToolUse.htm
before buggering it comprehensively. I've rarely come across the stud or bolt I couldn't remove safely by using the right techniques of which more and more force isn't the optimal option.
Spark erosion seems like a good bet now although a carbide milling cutter followed by careful drilling and retapping might work. No cheap options left though basically. Winding two nuts onto the stud first and giving them a good belt with a hammer would have freed it up almost 99.99% guaranteed. You live and learn.
Dave Baker
Boosted LS1 said:
^ Good read Dave.
It's from 30 years experience of stripping down hundreds of race engines most of which start life as rusty old donors the customer has sourced from a scrapyard or his own car. Getting stuck fasteners out has always seemed like basic common sense to me but when I watch other people struggle and break everything in sight I realise it isn't just common sense or at least perhaps most people just don't have much of that. It takes feel to realise when you're applying enough force to be risking snapping something and if it still won't come out now's the time to try another method.Last year I spent some time at a well known tuning establishment with time served mechanics there but none of them, despite years of experience, had a clue how to deal with a really stuck fastener. Exhaust manifold studs on cylinder heads must be the most common thing people break. The constant heat cycling weakens them and also promotes the corrosion that sticks them fast in the head. I've had to remove thousands of the buggers because I don't port a head until all the studs are out or you keep catching your hands on them and can't get good access to the port.
Just trying to wind them out with a stud extractor will break 10% of them on an old corroded head. Winding two 8mm nuts on just proud of the stud end and belting hell out of them first will free up nearly every one. Only once in a blue moon will I have to resort to even more drastic tactics like heat. I can't remember the last time I broke one and had to mill it out but half the heads I get sent have a broken one in it already that the customer 'forgot' to tell me about in advance. I don't forget the £40 charge to mill it out and helicoil it though
To the OP. If the remains of the stud are really flush with the head and not a couple of mm down then you might be able to lay a nut over it, weld that on with a MIG through the centre hole and then wind the lot out together. You'll need a decent MIG, ideally 180 amp to get good penetration. My little 130 amp one struggles with anything much thicker than sheet metal but it does usually manage such jobs eventually and it's paid for itself god knows how many times over.
Dave Baker
Going a bit off topic but Dave, thanks for the tool tips - I also enjoyed http://www.pumaracing.co.uk/customer.htm until I realised I'm a 'Type 2' 
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