Bisi header exhaust leak, any solutions?

[Jon]

I installed my Bisi header literally right after I passed emissions two years ago. Well I have to go get tested tomorrow, so I fixed an exhaust leak that cropped up over the winter. We had a sh*t ton of snow and ice, hit some large ice blocks... things under the car got knocked around a bit.

Well today I got everything nice and tight again, new gaskets, new hangers, even got my rear muffler re-aligned so it's not all cockeyed.
HOWEVER, the damn Bisi header is leaking. Before this winter it was only one of the four pipes where it met the collector (lucky me, right?!). And depending on the day, it would almost be completely sealed up
Now that I have readjusted everything it's leaking like a son of a bitch. Raspy sound under the hood when you're on the gas, that 'put put put' sound... and my favorite, a raw fuel smell in the cabin (not good).

The raw fuel smell may be unrelated, however it only now cropped up (coincidence maybe? ). I'll be checking the O2 sensor, TPS, MAP, fuel pressure regulator, ignition, spark, and of course fuel leaks around the injectors, lines, and fuel filter.

So here is my question... has anyone been able to find a solution for the Bisi header leaking (besides welding it together)?

I have some lap joint exhaust clamps (pictured below).

Hesitant to even bother because...
1). Not sure they would be able to slip between all four pipes where it meets at the collector.
2). All the sh*t that needs to be removed to have access to the collector area to put the clamps on...

So if ANYONE has this god forsaken header and has a solution for the leak, post up!

[F22Chris]

Exhaust paste maybe. Why is welding not an option?

[Jon]

Exhaust paste maybe. Why is welding not an option?

No welding is an option, I just like the ability of being able to take it off easily without disassembling everything.

[CyborgGT]

How often are you planning to remove it for that to be annoying? Welding's the only real long-term solution.

My idea for making it easy to actually access close to 100% of the piping is to cut off the cylinder 4 pipe. In this image, count out to the fourth little section of pipe that's welded in there, that second-to-last bend before it goes straight down to the collector. Cut it at that bend's bottom weld, as well as at the two vertical welds at the collector itself.



With that pipe out of the way, it looks like you've got enough access to completely weld up the three remaining slip joints. Then weld up the slip joint for the freed Cyl 4 pipe before welding the whole section back onto the rest of the header at your cuts. It looks like there's room enough to weld all the way around that top cut, with how it's bent away from the other pipes. As for the collector, I don't see you having any less access than whoever welded those four together in the first place.

If you can't get into the center of the collector, I can imagine one solution, but it involves more cutting and re-welding. Make a horizontal cut completely around the collector, a little ways above the weld at the bottom of the merge. That should gain you enough room to get your welder in there to seal up the center from the inside, then you can weld your cut back up. It adds a scar, but at least you know it's 100% sealed.

If all hope is lost, I'll take it . My plan is to get a replica one of these and sort of re-engineer the thing into a 4-2-1 to fix that mid-range dip.

[Jon]

Thanks, that does give me some ideas of how to fix this damn thing.

I guess I was hoping someone came up with a clever solution not yet discussed at one point or another about this header.

A large portion of the issue(s) with this header leaking is the piss-poor job they did aligning the collector with the downpipes too. They are just OFF like nothing else.

[CyborgGT]

I could never expect a perfect seal out of any slip-join. It's metal-on-metal contact, with no sort of gasket. I've seen that exhaust cement used (it's designed specifically for slip-joins, after all), as Chris mentioned, but is it going to last forever and not eventually develop stress cracks? I wouldn't completely trust it.