Topic: Exhaust Stud Bolt Orientation

[Ellz10]

Another noob question, but does the long or short threaded end go into the head for exhaust stud bolts.

[Flyin900]

I have always put the longer threads into the head part, as it is aluminum and the more threads secured means a better holding force. Others may have a different opinion.

[BenelliSEI]

I have always put the longer threads into the head part, as it is aluminum and the more threads secured means a better holding force. Others may have a different opinion.

+1 to that. However, if it bottoms out early and the shoulder sticks out too far, then turn it around. Safe rule is at least 1.5 diameters engaged. Even with the short end, you’ll get more than two dia.

[Ellz10]

I have always put the longer threads into the head part, as it is aluminum and the more threads secured means a better holding force. Others may have a different opinion.

So I tried putting the longer end in and tightened quite a bit, but didn't want to keep tightening as it got much harder to turn and that's with about 5mm of thread still showing that wasn't able to be screwed in.

So I suppose I should just turn it around and thread the smaller end in and call it good, eh?

[BenelliSEI]

Yes.... that would make sense. Use a drop of blue loctite so they don’t come out the next time you want to remove your pipes.

[MauiK3]

Don’t bottom them out. Back them off a bit, maybe half turn to be sure they don’t expand and put pressure on the casting.

[Ellz10]

I've always wondered if there's a set torque spec for these studs?

Yes.... that would make sense. Use a drop of blue loctite so they don’t come out the next time you want to remove your pipes.

Definitely doing this!

Don’t bottom them out. Back them off a bit, maybe half turn to be sure they don’t expand and put pressure on the casting.

Oooo that's a good idea. Thank you!

[calj737]

Use a drop of blue loctite so they don’t come out the next time you want to remove your pipes.

Blue doesn’t tolerate the heat that the exhaust will create, so in essence, it does nothing for retention. Red needs heat to remove it, so that won’t work either. Copper anti-seize should be used with the steel-alloy interface, but it’s not for retention but for corrosion retarding.

Tightening the nuts into the flange in turn adds torque to the stud, so they aren’t coming out as a result of inadequate torque.

[pekingduck]

With OEM studs, there is a more rounded end, and it points outward. The threads going onto the head shouldn't bottom out, so the thicker unthreaded portion needs to jam into the casting to apply tension to lock in place.

[Ellz10]

Use a drop of blue loctite so they don’t come out the next time you want to remove your pipes.

Blue doesn’t tolerate the heat that the exhaust will create, so in essence, it does nothing for retention. Red needs heat to remove it, so that won’t work either. Copper anti-seize should be used with the steel-alloy interface, but it’s not for retention but for corrosion retarding.

Tightening the nuts into the flange in turn adds torque to the stud, so they aren’t coming out as a result of inadequate torque.

I thought about that as I was applying the blue and stopped because it obviously doesn't make sense to do it. I'll have to get some copper antisieze.

With OEM studs, there is a more rounded end, and it points outward. The threads going onto the head shouldn't bottom out, so the thicker unthreaded portion needs to jam into the casting to apply tension to lock in place.

Yep! So I looked and the rounded end is correctly sticking out. Thank you for this.

[BenelliSEI]

Use a drop of blue loctite so they don’t come out the next time you want to remove your pipes.

Blue doesn’t tolerate the heat that the exhaust will create, so in essence, it does nothing for retention. Red needs heat to remove it, so that won’t work either. Copper anti-seize should be used with the steel-alloy interface, but it’s not for retention but for corrosion retarding.

Tightening the nuts into the flange in turn adds torque to the stud, so they aren’t coming out as a result of inadequate torque.

Totally true!

[MauiK3]

A 6mm thread does not want much torque. Maybe 70 inch pounds