problem with gibson headers

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Supercharged111

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The V-band clamps I've used most had stainless-steel studs and nuts. They were good for one tightening. Once tightened, the stainless nut galled the stainless stud. The stud broke during disassembly. Every. Time.

It may be that some anti-seize applied to the stud would have prevented this, but The Bus Company didn't provide us with any, and anti-seize wasn't on the Bill of Materials for this operation.

I always felt sorry for the poor bastage that had to work on that assembly in the future. Those clamps were really expensive.

The V-band clamps I use personally aren't on exhaust systems, they don't have Stainless nuts/studs on them, so they go on and off repeatedly with no problems.

Well, I think that's something I should look at sooner than later. A simple mild steel nut should prevent any galling.
 

Erik the Awful

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The V-band clamps I've used most had stainless-steel studs and nuts. They were good for one tightening. Once tightened, the stainless nut galled the stainless stud. The stud broke during disassembly. Every. Time.
What were you torquing them to? V-bands use a very light torque spec, like in the neighborhood of 15 inch-pounds.
 

PlayingWithTBI

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A simple mild steel nut should prevent any galling.
Years ago when I was working at a food plant, all we used was SS fasteners. Fastenal ones galled all the time. When I switched to Lawson hardware we had no more issues. The Lawson Dude explained they use 2 different alloys for bolts vs nuts which eliminated the issue.
 

Schurkey

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Lawson is good stuff.

Fastenall is...not. If you're lucky, you get Taiwanese hardware.

The Bus Company used to buy Canadian hardware--nuts, bolts, washers. They switched to Lawson and had fewer problems. I got a small assortment and bolt cabinet from Lawson as a thank-you for pushing for the change. Didn't expect that.

I don't remember who manufactured the V-band clamps, except that one came on every Detroit Diesel "crate pallet-engine" we installed. I also don't remember the torque we applied.
 

95burban

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The V-band clamps I've used most had stainless-steel studs and nuts. They were good for one tightening. Once tightened, the stainless nut galled the stainless stud. The stud broke during disassembly. Every. Time.

It may be that some anti-seize applied to the stud would have prevented this, but The Bus Company didn't provide us with any, and anti-seize wasn't on the Bill of Materials for this operation.

I always felt sorry for the poor bastage that had to work on that assembly in the future. Those clamps were really expensive.

The V-band clamps I use personally aren't on exhaust systems, they don't have Stainless nuts/studs on them, so they go on and off repeatedly with no problems.

We use a ton of SS hardware on our exhaust and use anti-seize on everything. One day i didn’t have any and used milk of magnisia instead. Everything on my boat is SS also, looks pretty but damn what a pain in the ass.
 

Erik the Awful

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I did a lot of v-band clamps on bleed air hoses over the years, and I had a few of the nuts strip, so it's not uncommon. We weren't allowed to anti-seize the threads and that wasn't an issue, but our bleed air hoses didn't heat cycle every day like your exhaust. We were flying heavies, so the air start carts only got used when they needed to pressure test the cabin. Our biggest issue was crewchiefs dragging the coupler, which scratched up the clamp and stud.

After you get the flanges mated together, slip the clamp on, and throw a nut on the stud, take a small rubber hammer and tap all the way around the coupler with the hammer to seat the clamp onto the V. Then tighten the nut. This way you don't use the nut to take up the slack in the clamp and the threads last longer. Once you have it seated, torque to spec. I was thinking it was a lighter torque, but it's 45-55 inch-pounds. Mind you, we were holding back a staggering volume of air - you can probably get away with less. In my entire career I never saw a V-band clamp fail; the bleed air hose always gave out first.
 
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