As the title suggests, I just replaced my exhaust studs, the front ones to be exact. There was just a single broken one there, and I think one or more are broken at the rear but that’s for later.

The problem is, I have some reasons to doubt my success. It still sounds like there is a broken stud on the front, even though I replaced all 6. I heard this on the first start. Is it just my imagination, or is it possible that a new stud broke immediately after installation? Could it be one of the 3 y-pipe studs? Is there a normal brake-in period during which the nuts/washers/shims/studs/gaskets all settle in? I also saw a bunch of smoke at first, but I am very sure that it was just PB Blaster evaporating.

I followed all the FSM torque specs as best as I could, it was very difficult getting a socket and a big torque wrench in some of those places, but I am very confident that I got within the limits. I only have doubts about the way I torqued the y-pipe. I tightened it to the header but not all the way, then attached the y-pipe to the cat and torqued it all the way, then the front header nuts, and then the rear header nuts.

Please let me know if you had a similar experience with the noise, otherwise I think something went wrong with my repair. In a few hours I’m going start it up again and do a few more things, maybe I’ll be lucky and it will sound better after cooling down.

And no long post is complete without a photo, so here you are:

 

Just went for a test drive. It seems like everything is fine, and there is definitely more power. It probably just needed to warm up and cool down in order for everything to settle in.

 

You can have the same kind of exhaust leakage where you didn't tighten up the y-pipe all the way. Mine started out sounding like a little tick, then slowly became a terrible sound. The metal "o" ring gasket had flattened out on the y-pipe, but I think if you don't tighten it enough, you will have the same effect.

 

I replaced the gasket, and tightened to the torque spec. I think its better now, but I was really worried about having nothing to show for an entire saturday under the car.

I've also realized that I need a new set of 1/4" extensions and a 1/4" torque wrench if I ever hope to tackle the rear studs. My 1/2" wrench was a very tight fit in the front, and even worse when dealing with the cat bolts because of the orientation.