brass exhaust nuts

[tavspeed]

i have the taffspeed m7 allen bolts,fit and forget,better with a stub manifold as against a u bend type manifold,dont know where he gets them from,but i searched high and low for some with a full thread,found some s/s ones on a mountain bike shop web site,only slightly cheaper and you would have to drill them,cheers all.

[dutch]

sorry Andy- I disagree.

They are supposed to go on with the "round" bit against the manifold flange- the area is so tight, it is very hard to tighten them up if its done your way.

Check out page 18 of the old work shop manual (4th edition)

Chris

so would you use a washer and if so which one

[yozzer]

maybe i'll use hex up and use a bent over tab, I just don't want the feckers coming undone.

[HxPaul]

sorry Andy- I disagree.

They are supposed to go on with the "round" bit against the manifold flange- the area is so tight, it is very hard to tighten them up if its done your way.

Check out page 18 of the old work shop manual (4th edition)

Chris

so would you use a washer and if so which one

Use a wavy washer or a spring washer.

[slangen]

i have the taffspeed m7 allen bolts,fit and forget,better with a stub manifold as against a u bend type manifold,dont know where he gets them from,but i searched high and low for some with a full thread,found some s/s ones on a mountain bike shop web site,only slightly cheaper and you would have to drill them,cheers all.

Exactly, I tried finding high tensile m7 Allen bolts and found some but it was not cheaper and not drilled, I'd rather support a top man like Ian.

I use a pair on a u bend exhaust and its not a problem, I cut of 6-7mm of the bolts, job done. Much easier to undo with allen head, just undo a bit on each side at a time, you can reach them under the head cowling...

[HxPaul]

They're supposed to go on with hex. side to the manifold flange with a spring washer underneath. This way gives the greatest surface area contact.
They are made of brass because the combination of extreme heat and exposure to the elements, would make steel versions lock solid on the studs in no time. The nuts are deliberately weaker than the studs to make difficult removal unlikely to damage the studs.
The nuts should be considered as consumables.

The nuts are designed so that when they are tightened the round part deforms and grips the stud,if you put them on the other way up,with the hex. side facing the manifold the round part of the nut never tightens against anything and so never deforms to grip the stud.

[Chris in Margate]

I started legally riding a Lambretta in 1967 and have spent over 40 years tightening with the hex against the manifold because that was how all the Main Dealers at the time returned the scooters after they had gone in for the obligitary exhaust stud repair. My first LI 150 «S2 (used) was like it when I got it and everybody I knew tightened that way.
I started putting them on "round side first" only last year.

I'm still not absolutely sure !

[YAMLAM]

why bother putting the round bit on if the hex goes against the manifold ? may as well have hex both ends, like a std nut. seems logical thinking to me that the round bit goes against the manifold.

[Timbo]

Just what I was thinking..

[bristolmod]

oh this ones gonna run and run.................