Header swap headache, or FML

[TimT]

2007 Cayman base model, started throwing bank 1 codes a while back.. clear the code..sometimes it would take a week to come back.. recently down to a single outing...

OK one of the Cats is failing..

My good friend Bill Rudtner, had a set of take off Fabspeed headers with sport cats, a deal was made, and Bill let me use his shop a bit.. Passenger side came of with only one broken bolt (WTF Porsche, bolts? seriously)

Driver side every bolt sheared, even after cycles of heating to cherry red, cooling rinse repeat.

And in my zeal to defeat the broken bolt problem i cut all remnants of the bolts (should be studs) off.. MY bad, I effed up..

Car off the lift, pushed out into the lot

Heads are being scratched, my little over zealousness with a cut off wheel made a PIA job, into a MEGA PIA job.. the reference for the Stomksi Jig were lost...

Bill and I left and tried to figure out how to proceed, we needed one good hole on center to locate the jig.. and due to Bills Yoda like skills we (he) managed to hand drill out one of the studs close to center..)

And he had a great idea how to locate the jig using one off center stud.. Locating pins...

After we got one drilled out enough to hold the fixture tight, we spent quite a bit of time locating and centering the fixture. Extra holes were drilled through the fixture, and into a meaty part of the head..and pins were used along with the one semi good stud we had... then drilling and tapping commenced...


Pictures...

Sorry I can't find the pic of all six closely cut off bolts..(found a pic on Bilsl instagram)


Broken studs! Yay! all six!

This is the witness drilling in the head, its about 0.25" deep






Locating pin




Fixture showing location for pin




Pin installed




Array of of cutting tools used.. the long drill are needed where the engine # boss interferes with an exhaust hole on passenger side...




End mills make easy re centering slightly o/c drillings.. they are fragile Bill broke one, guiding into the drill bushing

Even with the fixture, and guide, you may get this



Done..

[tcora]

I hesitate to ask - how many hours in the job all told? Your perseverance is impressive!

[TimT]

I'm thinking 12-16 hours.. This was done at Bills shop at his convenience over the course of two or three weekends.

It was all done by me, when I got jammed up, Bill showed me the way.

It took half a day to remove the old system.. All six of the header/muffler studs had to be burned off..

I've had pretty good luck with my 911's inre exhaust and muffler work, if I could see the future and see that 8 of 12 bolts would break ( f/u Porsche) I would have skipped the heating to cherry red non sense.. and just broke the bolts, and dove into drilling..

I then got carried away cutting the broken studs, so didn't want to have to drill anymore than I had too.. So I cut a good reference away


Fixture located with pins and the "close" stud we drilled..

Note to users: drill close to where the fixture is fastened, it can walk if drilled at opposite end



Pretty corrosion resistant studs