Hi,
Managed to get the other five y-pipe/manifold nuts off today without breaking any more studs .Purchased some 3-IN-ONE professional high performance penetrant spray this morning.It's made by the WD-40 company,but is more powerful than the regular stuff,did the trick anyway.
Four out of the five remaining nuts came undone and threaded back down the studs.The last one came out wholesale,the nut stayed rusted to the stud and the stud unscrewed from the thread in the manifold.I can put a new stud in it,have some 3/8" Unc bolts I can make some studs from.
The next job is to try and remove the stud I sheared off the other day,luckily there's enough sticking out to get some grips on it,so maybe I'll be lucky and won't need to drill it out,we'll see .Anyway that will have to wait until tomorrow,it's well and truly dark here now.
Damn cold here today,at least it didn't snow,like they forecast.Hopefully it will be dry and bright tomorrow as well.It really sucks not having somewhere I can work indoors.
Fired it up after removing the y-pipe/cat assembly,sounded nasty as hell,like an old school muscle car .
Will keep you posted,best regards,Mark.

 

I use a hair dryer when im working outside and it makes it a lot nicer. I usually heat the tools up since a metal wrench sucks to hold whens its freezing.

 

Hi,
Had a good look at the old cat/y-pipe today.Gave it a good shake and there were broken pieces rattling around inside the cat ,so that speaks for itself.I removed the old drivers side oxygen sensor from the old y-pipe,came out real easy,which was a pleasant surprise.The inside of the pipes looked pretty black,appears to have been running a tad rich,which is probably what killed the cat.Will fit my new plugs and coil before installing the new cat/y-pipe.
Just out of curiosity I weighed the old and the new parts.The old set up weighed 21 lbs and the new one just 16 lbs,plus the pipe diameter on the new one is about a half inch bigger,so it should flow a tad better.
Going to soak the sheared off stud for a few more days to give me a fighting chance of removing it,don't need any more headaches.
There were no gaskets where the y-pipes met the manifold,just fits together the same as where cat-back exhaust joins the cat.A sort of male to female affair,no pun intended.
Will post up again when I get the new part fitted with the results.So tempted to take it for a drive with open manifolds to see if the problem is solved,but don't want to get pulled buy the Police.Two patrol cars have cruised by whilst I've been typing this,almost like they're waiting for me .
Regards,Mark.

 

Changed my mind,just got back from a test drive .
I am now pretty sure the cat was the problem,the neighbours now hate me,but who cares,an open headered LT1 never hurt anyone .
No bogging down,just pure noise,raw power and the smell of burning penetrating oil,can't beat it .
Just did a half mile trip,like I said I didn't fancy getting pulled by the Police.Sounded awesome on deceleration,popping and banging,everyone was staring,**** 'em,they'll live.
Thanks guys

 

You just had to do it

 

Hi all,
The car passed it's "Ministry Of Transport" test today .
The emissions were all fine and it sailed through the test.
A big thankyou to everyone who helped .
Regards,Mark.

 

Sweet deal.