Exhaust gods were pleased yesterday

[Dr.Fiero]

Clearly, my blood offerings made them happy.

I got the manifold on the bench, with.... count 'em.... ZERO bolts broken!
Mind you, there was one missing to start with. So that skews the count.

I would like to thank the wonders of Lloyds Moovit - the very liberal and repeated application of which made this all possible (IMHO).

Turns out the manifold wasn't even cracked as suspected! 4 of the 6 ports showed signs of leakage on the gasket.
I'm thinking that it's been replaced before, and whomever did it took "don't overtorque the bolts" too much to heart.

What's the feeling on the use of blue threadlocker? What I'd really like to do is use studs instead of bolts!
When I used to work on Fieros round the clock, I was selling stud kits for them, since they had the same issue but worse.

 

[Mooseman]

When I replaced the manifold on my '02, I used black 10.9 grade bolts instead of the stock stuff. They held up great and never had to retorque, without thread locker. There's no point in my mind in using thread locker since they get hot anyway.

Studs might work if there are any that fit. Might interfere with the heat shield though.

 

[I_Shoot_Back]

thread locker is awesome for later when one breaks and you try to remove the remainder

 

[Dr.Fiero]

Studs might work if there are any that fit. Might interfere with the heat shield though.

I'm actively researching and experimenting on this right now.
If/when I come up with a solution I'll post my findings!
I got it figured on the Fiero many many years ago... sure I can do it again.

And they shouldn't interfere with anything, as there will be not much more sticking out than the head of the bolt would be.

 

[Mooseman]

If there are studs for LS engines, I think they're the same thread.

 

[Dr.Fiero]

If there are studs for LS engines, I think they're the same thread.

Some are (M8*1.25). Some of them (not sure which) are M10 though, so beware!

I'm picking up some samples this afternoon (hopefully) to try. Located a good source on nuts (serrated face flange).
I might have to buy in multiples of 100, so if anyone needs a "kit" after, it looks like I'll have spares!

 

[cornchip]

All the exhaust tapped holes are M8-1.25. ARP has both studs and purpose made bolt kits to replace original LSx bolts. The LSx bolt kit is the best bang for the buck in stainless as one kit will do the whole 4.2 manifold. For good measure, I went to a local industrial nut and bolt to get 'hardened' washers to go beneath the M8 bolts. Things need to be able to expand with the heat and not put the sideways stress on the bolt. I'd think twice before I'd throw a grippy serrated flange under a bolt head in this application.

 

[Dr.Fiero]

Just to be clear - I meant that some LS (loose use of the term) exhaust are M8, and some are M10 (either one, or the other).
Of course, ALL 12 of the 4.2's bolts are M8.

I looked at the ARP one's - ouch on the price tag (~$160CAD). Yes, they're pretty. Yes, they're tough.

At the point I'm at now, I think one set (studs, washers, nuts, *12) of the one's I've got will total about $20CAD

 

[Dr.Fiero]

Success! It all fit together like a glove. Love it when a plan works out the first time.

Fired it up to do the burn off (oh, remember to turn OFF your HVAC first! Oops), and it was as smooth and quiet as I've ever heard it (since it's leaked ever since I've owned it!).
Idle is of course better, since it's no longer inhaling air from 4 of the ports, causing a fake lean out that then gets crazy enriched.

Heading out for a bit, after I get back I'll slap the last few things on, then take it for a run. But based on what I've seen so far I'm sure it'll be much improved.

 

[cornchip]

ARP's are pricey, especially when your in Canada. I expect things to get worse with NAFTA falling apart and Trump going to war with Canada plus the rest of the world on trade. That's about as far as I'm going with a political view....so I'm done.

That ARP kit I bought HERE to replace the originals on my swap project (2008 motor). I had the last bolt at the rear broken when I bought the motor. Drilled it and helicoiled to repair. My 2007 Trailblazer hasn't showed signs of breakage yet, but I'd be afraid to try and remove any of them.

 

[Dr.Fiero]

I'm going to drive on this for a while, and make sure all is happy.

I had to buy in bulk;
So if anyone else in CANADA wants, for $25CAD including shipping (mail), they can have the same set of studs, washers, nuts I used.

No idea what it would cost to send south, so I'm just sticking to north of the 49th.