heli coil time
 

So the saga continues...there was enough bolt sticking out originally to put a nut on, mig weld and back off. Not now! With all of the heating, drilling for an easy out, broken easy out in the bolt, more cutting, drilling, I am left with what is now a stripped hole in the head. So now to install a helicoil. I know about being careful with the depth and being extremely precise with the drill so the bit does not wobble and make too large of a hole. I have ready the thread mentioned about installing a heli coil. Any other tips?

Strangely, the heli coil thing does not really seem so scary after taking a torch to the car, cutting the bolt after the easy out broke, and then using a tap to slowly nibble away the last remaining bits of the bolt.

The bolt was on the row / side that is closest to the block.

The header bolt is really not a huge deal, the car drives fine, has a slight exhaust leak that would only be noticeable to a trained professional or a Boxster nut, and is a simple annoyance that bothers my anal-rentetive side enough that I will probably repair it.

What an adventure! On a good note, my engine cutting out issue turned out to be a simple MAF cleaning and reset of the ECU.

My tip, if you are thinking about heli-coiling, is to not use heli-coils, but use time-sert. They are a much higher quality product than heli-coil; a solid bushing insert that is thinner, so you won't need to drill out as large of a hole. The set will come with the proper size drill, counter-boring bit that will cut the proper depth counter bore at the outer edge of the hole, tap, and the installation tool that rolls bottom threads. You will need to figure out what depth bushing you want and order that.

++ TIME-SERT Official Threaded inserts for stripped threads, blown out sparkplugs,

Also, use anti-seize on new bolts to prevent this from happening again.

Please heed his advice. Take the easy out now and throw it away. It will break off and you will not get it out. I learned that lesson with a moto. I broke off an easy out in the motor case. It cost me $750 to have a machine shop use a laser to vaporise the easy out.

Did you ever get this sorted out. I hope it ended well.

all ended well
 

I was able to clean out all of the old bolt with a tap and the threads are strong enough for an original (new) Porsche header bolt to not only hold but get torqued down and not leak.

What a pain in the butt! I spent 2 hours very slowly and carefully cleaning out the hole with the tap and got lucky that I did not mar the original threads.

No more exhaust work on this car for me!!

New carbon steel bolts ? Anti-seize?
After so many hours and $$$ of removing broken bolts we replace them with the same grade bolts?
Considering the frequency and expense of this issue ,it is surprising there isn't a little more interest in using the inexpensive, simple to install s/s stud kits mentioned earlier.
If intelligently installed, s/s studs will work perfectly for more many decades.Carbon steel bolts - not so much.
It would be poor engineering practice to use anti-sieze in this situation. It will complicate the choice of effective torque settings for the bolts because it acts as a lubricant. IMHO the correct grade of Loctite is better choice for exhaust bolts, studs & nuts( different grade for each) .
Loctite effectively deals with the conflicting issues of heat cycling, dissimilar materials, vertical installation, vibration and ability to remove the studs.YEMV.Suggest a visit to the Henkel tech section.