engine and drivetrain Ie Headers Are Leaking

[Mitch_M]

What started with a transmission mount swap led to me making a new exhaust. I noticed when I was swapping the trans mount that one of my center resonators on my old style (2 resonators) IE exhaust was cracked, seeing as it's the second time this has occurred (the first was at the muffler), I decided to go down to the local exhaust shop and get some pipe and put together a new center piece. After getting everything back together, I noticed that the IE headers are leaking at the clamp. Anyone have this problem before? How did you fix it? I tightened the clamp as much as I could. TIA.

[FB73tii]

Picture would help. Is this a butt joint with a band clamp? if so, the OD's of the header end and the other pipe are just slightly different, enough so that the band clamp only tightens fully on the larger OD. Had this issue with my truck--3" cat back, 3" pipe from cat to cat back, band clamp tightened but cat back will rotate end eventually come out. MIG solved this one. But, the exact same band clamp works fine on my Stahl header with 3" collector and the same 3" OD straight pipe. Go figure.

 

Edit, and the band clamp also works with my 3" IE header collector on my other car! --Fred

Edited September 1, 2014 by FB73tii

[Mitch_M]

Fred-- It is a band clamp. I checked again a little while ago, and the collector is on as far as it will go. Clamp is tightened as much as It will go, but it's not closed completly, meaning the two ends of the band are not pinched completely onto the spacer in between them (I'll snap a photo in the morning when it's light out to show you). My dad suggested putting in a thin layer of shim stock between the header and the collector, then tightening the clamp down. Do you think doing so would solve the leak? If the issue is that the band clamp is only tightening on the OD of the collector, I would think using shims wouldn't help anything, but it may be worth a try.

['76mintgrün'02]

Here is a thread where this is discussed.  Roadhog added some washers under the clamp nut and it worked for him.

 

http://www.bmw2002faq.com/topic/156103-ireland-eng-stainless-exhaust-system/page-2?hl=stainless+exhaust+clamp+shim#entry994985

[Mitch_M]

MIntGrun-- Thanks for that link. I tried searching for something like that. I'll try adding washers or removing the spacer tonight and report back.

[FB73tii]

I thought about a shim but it would have to be very thin and match the thickness difference very closely. Hobby shops carry very thin brass sheet. My clamps are different than the ones in the linked thread, they are about 5" long and have two bolts. I tried modifying it for more clamping force but no go.

 

Edited September 2, 2014 by FB73tii

[BobBreed]

I had the same problem, ditched the band and added a regular muffed clamp.

[FB73tii]

I had the same problem, ditched the band and added a regular muffed clamp.

Hmmm, not sure how a "muffed clamp" would work with a butt joint. Remember, a butt joint connects two tubes of equal O.D. Other methods of joining are adding flanges of some sort, like a V-band clamp. I am not familiar with the header being used here--is is perhaps a lap joint instead? I.e., one tube fits inside the other. In that case, slotting the outer tube will allow it to crush a bit more under clamping. Here's an image of a butt-joint welding jig:

 

[Mitch_M]

Fred-- After hearing that great explanation, I realize now that it is a lap joint. The header slides into the header collector (which is slotted) using the band clamp to tighten them together. The problem I'm having is I think that the band clamp on the header collector is not tightening down enough to completely seal off the exhaust. I think I was able to tighten it enough last night, though, by using a jack handle on the end of my wrench for a little extra leverage. But now I have a leak elsewhere according to all the popping on decel/faint exhaust fumes swirling around the cabin. The journey continues haha.