Bonneville America Forums Forums Technical Forums Exhaust Header installation

I removed my head pipes and sent them off for ceramic coating. As I was taking them off, one of the studs on the cylinder came out along with the nut, so I decided this would be a good time to remove and replace all of them. So, when reinstalling, how should I go about doing it?

I double nutted them for removal, but what about installation? It appears that the studs came with some kind of thread compound already on the part that goes into the head, so I shouldn't add anything else, correct?

I'm assuming that thread compound isn't needed on the exterior portions as they have locknuts.

I know that many of you have done this before, but my shop manual doesn't really give me much more than a torque setting and fitment instructions.

Thanks,

Ted

I'm sure somebody will disagree with this, but I was taught to install studs that are subjected to high temps with anti-seize. Even red lock-tite is useless under temperature. So I say chase the female threads clean, anti-seize and torque to spec. Always has worked for me, from steam and gas turbines to lawnmower motors, anyway.

Ah, yes. The anti-sieze debacle. Some will correctly argue that any lube on a threaded connection requiring the adherance to torque specifications will skew your set torque. However, I believe that a slight deviation on the setting in this application is surely better than a siezed stud later on. I'd slap the stuff on and go a tad light on the torque. They're probably gonna loosen up a tad anyway and you can lightly snug or re-torque from there. To keep the threads clean outside the nut in the futuer so the stud has less chance of spinning out, you may consider an accorn nut of some kind or double nut to cover the exposed threads of the stud and anti-sieze the crap out of them as they would not be subject to any torque requirement.

Contraire, a series of threaded fasteners dimensioned similarly, lubricated prior to torque sequence will always yield the closest attained level of compression and stretch as to bolt to bolt variation. Ask a mechanical engineer, had enough of those guys tell me that at work, yet again.

yeah just screw them on

You're on the right track, double nutted and anti seized studs; that red loctite will just melt at the exhaust temps anyway.

actually I thought the new studs came already coated?

I checked with the dealer, and in fact the studs do come already coated with an snti-seize compound. So I guess I don't need anything. Thanks for the idea on adding an acorn nut, I'll give it a try.

And what REALLY sucks is that when you take it to an authorized dealers shop, some of the mechanics will do it one way, and others will subscribe to the other theory!

I got me a big can of Nuclear/Powerplant grade of anti-seize (non-metallic) on the bench, and I wouldn't be afraid of using it on anything that may need to come back apart in the future. I have as per installation specs applied anti-seize from everything from the top dome bolts on the largest blast furnace in America to 2mm bolts in clean rooms under construction. I was introduced to "Millwright Mayonnaise" in 1970 and old habits are hard to break.