What's the trick for sealing the exhaust nut?

[clouseau]

I finally realized after a month that that ticking noise coming from the left side of the motor was an exhaust leak at the nut.  I took it to a BMW shop who had the tool and we removed the nuts (they came off super easy) and header.
The header was not fully in (about 1/2 inch more to go) and the exhaust nut washer on the leaky side was backwards.  Still after correcting both, it still leaks a bit, albeit not as much as it did.
The mechanic said that is normal. I beg to differ.  I just ordered my own nut wrench from Capital Cycle, but my question is:
When these start to leak is it just a fitment issue (ie a trick to getting it sealed) or does the nut or washer need replacing?
The mechanic I went to has an R65 he is parting out that is in very good shape, so getting parts is not a problem.

[Bob_Roller]

First question that I have, is : Was the entire exhaust system disassembled when your mechanic performed the work ?

This is just a guess, based on my experience, that the crossover pipes need to be loose on the header pipes and preferably not have the mufflers attached to the pipes as well, to get the header pipes back into the cylinder head port  properly.

[clouseau]

Bob,
We did not loosen the crossovers, but did remove the exhaust pipes and the 2 clamps at the rear of the headers.  I can see the benefit of loosening the crossovers. I will try next week when I get the tool.
Side note: The mechanic refused to tighten down the nuts beyond snug given their infamous reputation of seizing on.

[Lucky_Lou]

I had a perforated down pipe near the silencer clamp which i sleeved with a stainless tube as there is a sleeve adaptor for 38 to 40 mm it blew a bit at first so i bought a tube of exhaust sealant and coated it...it worked a treat.I would try a bit on the clamping ring behind exhaust nut and put copperslip or something similar on the threads.
Lou

[Bob_Roller]

The maintenance manual torque specification for the exhaust nuts, believe it or not, 100 ft/lbs .

I just snug them up with the exhaust nut wrench, then give it a few taps with a large brass hammer .

Don't forget to use an anti-seize compound on the threads, or they will seize, not maybe .

[nhmaf]

I would DARE to go anywhere near 100-ft-lbs on those babies!   I snug them up gently with the big "War Club" wench (After cleaning and coating threads on head with anti-seize) and leave it go at that.   I think I'm probably in the vicinity of 40-50 ft pounds (I think) - I run it it and if there is an audible exhaust leak and/or I see some anti-seize bubbling out I may snug it slightly more.