Broken head studs are common in Porsche 911 engines. This video shows how you can extract broken studs with only the tappet covers off. You can probably even do it with the engine still in your car. I made a tool based on a Koken 8mm nut twister - and this grabbed the broken studs "down the rabbit hole". It took a great deal of torque to get the studs out, but the tool was up to the job.
P.S. Here are other ideas related to 'Plan B'. I didn't need to do any of this stuff, as 'Plan A' worked on all 4 studs.
I originally intended that the 'Plan B' tube should be heated at least red hot before tapping it as far as possible onto the broken stud, then it would shrink and grab the stud more tightly as it cooled. You can see from the color in the video that I did heat the tube to try to remove it - it actually grabbed on more after that! I would incorporate a slide hammer for removal of the tool if needed! I would also make the tool longer so that you can cut off the end after each application, and have a fresh section for the next stud.
If the tool slips, not all is lost ... clean the tool and stud with brake cleaner, then fill the tool (which will now have a ~loose fit) with a few cc's of Loctite 680. Tap it onto the stud just a little bit and hold it in place for a few seconds, so that the Loctite fills the space just above the the stud, and then tap it on as far as you can. If the engine is still in the car, let down both tires on the far side so that the Loctite flows down to the stud :-) . Tomorrow is another day.
A crazy idea is to drill the full length your tool, tap it onto the stud, and then insert a MIG wire down to the top of the broken stud. No inert gas needed down there! The heat of the weld could melt your tool before grabbing the stud sufficiently. And so much local heat in the guts of your engine! Of course you would need to insulate the MIG wire almost all the way down there ... ideally ceramic, bits of spark plug or whatever. You would have to be desperate!! Better to dismantle the engine. Whatever, don't try this idea without first developing and testing it on the workbench - you might find a strategy that is safe and effective.
I hope you have as much good luck and elation as we did!
4 фев 2024
