Connection at Y-pipe and cat on '93 3.0 4x4

[Fairlaniac]

I'm doing some exhaust work that failed inspection, cracked RH manifold and deteriorated gaskets between Y-pipe & Cat. 4 of 6 manifold bolts broke. Got them out then off to the "easy" part of the job loosening the three nuts fastening the cat to the Y-pipe. The nuts were rusted to round corners. So I used a cut-off wheel for the top inside and bottom. However the top nut towards the frame rail is basically not accessible by most tools. Trying things I put a 1: slice in the y-pipe but I can weld that shut. What I didn't realize was the y-pipe has an extension past the flange that appears to go inside the cat flange. So I cut through that and figured I'll need to deal with that later. So I'm committed with the sawzall and I've gone through three blades trying to get though that one Cat stud. Are they of a different material? A magnet sticks so I'm assuming a ferrous stud and nut. So I'll get more blades today and get through it. I guess I'll need to grind out the stud remains in the cat and use bolts to get it back together.

My main concern is that extension of the y-pipe going into the cat is oval. I don't know if a flange to flange fit with the gasket only will seal it? Has anyone else dealt with this in a similar manner?

Thanks!
Doug

 

[funguy26]

50206 Walker Exhaust

 

[rumblecloud]

I'm afraid I won't be of much help other than to commiserate with you. When I did my 94 4.0 the Y-pipe was oval, but so was the Cat, so it matched up with no issues.
Good luck with that sawzall. I remember that part all too well.

 

[Josh B]

That extention gives it two staggered layers helping to prevent blow-by, I suppose it's possible a pinhole there could turn it into a torch

why are you cutting the bolts? I'd be using the stubs to grip what's left of it