Thorley's
 

Folks,

What's the best way to connect the thorley's to a DP?
I see threads with people welding on a flange - I'm concerned about welding to the thorley DP as it will start rusting regardless of ceramic coating.

Thoughts?

Mines rusting anyway and I just welded directly to it. So I say do what you want.

the thorley's rust just like any other mild steel, they are a joke when it comes to their claims of never rusting. I have never had an OBX header rust to this day, and mine still havent even after a harsh winter. Go with whatever you think will seal best, i tried a vband, wasnt happy with it, went with the hedman ball flanges instead which you have seen already.

10-4; I'll keep that in mind.
So there's no point in re-coating if I do weld a flange on?

I'll be happy so long as I don't have any holes to patch in a few years.

My OBX actually had welds break on them (this was on my 3100 Malibu, the headers didn't even clear the heads, had to have one runner re-shaped); I had a previous horrible experience with them, mind you people have had better luck with them on the ls4 by the looks of it.

welds breaking apparently is a common thing on any made in china headers, ive seen it happen on all kinds of brands not just OBX, doug thorley though, and JBA, sadly ive seen rust horrifically. My buddy put a set of doug thorleys on his truck a couple years back and they were developing rust a month afterwards, after a year they looked like the exhaust manifolds that came off.

Now that sucks - you pay good $$ you at least expect them to last; I've thought about trying fireball coatings here where I live - they've got a really good rep and will coat a set of headers for $225 Canadian inside and out..

Mine have not rusted at all to this day 4 years later. I have a flex welded on the end of the dp and the rest all aluminized steel, I always use exhaust paint though frome dp back on my exhaust so I never have that issue. All welds fresh out the shop or if I do them at the garage get painted immediately

I have a flex right after mine too with all 304 SS. It's just the last 2"-3" of the DP that has surface rust. The rest of the headers are doing fine. I did not paint mine however.

this is the set i was gonna buy used before i went with OBX


http://www.hostthenpost.org/uploads/...fd29fde7e4.jpg
http://www.hostthenpost.org/uploads/...7ee5ecba52.jpg

Sweet jesus that's horrible...
Alright; I'll make sure the welds are painted and get a good flex welded onto it.

What are some good header bolts to use? I assume steel multi-layer OEM gaskets are the best bet?

Thanks!

Mike

https://cimg3.ibsrv.net/gimg/ls1tech...6735c5affb.png

How mine I'd setup


https://cimg8.ibsrv.net/gimg/ls1tech...b63ca2c097.png


Thorleys still looking good years later even with e85 daily and nitrous

Damn that's a tall ass oil filter. No drain plug on that tranny pan with as many filter changes as you do?

u live in arizona man,nothing rusts lol

Thanks - gives me an idea of what needs to be done.

Any feedback on header bolts and gaskets?

I don't know the part no, but I would say use some ARP 12 point header bolts. They're pretty nice. Otherwise new stock bolts should work I believe.


The stock metal GM gaskets should work. Rock Auto has a good price on them.

stock metal GM gaskets work fine, never had an issue with them on mine even though i did wind up going to felpros afterwards in a search for an exhaust leak. Those dont leak either. I had alot of bolts from mcmaster car in varous lengths so I used grade 10.9 hardened steel bolts. You just have to account for the flange thickness change over stock to make sure you have the appropriate length thread, i wound up with a slightly longer threaded bolt because the OBX flange was thicker then stock.

Thanks dude - where did you're leak end up being? Any areas that I should worry about leak wise?

Mine was and still is at the rear header connection, because of how fuckin impossible it is to properly access that section once installed. The original "band" clamps that they give you are junk, toss them immediately, you want a "lap joint" style band or something that compresses around those two intersecting pipes and seals over a wide area and provides even pressure. While ubolt clamps are fine at tail sections, they will leak up front.

You can see here i was able to change mine out with a u bolt and get it tight but it relies on a pressure seal rather then a physical seal. Look at that clearance, ugh.

http://www.hostthenpost.org/uploads/...6705430f34.jpg

Quite possibly the most retarded header design ever.

Understood - I cannot stand leaks.
Malibu blew so many catalysts because the fueling gets thrown off.

Anyone else have leak problems too?