Are there exhaust nut thread size variances?

[kommando]

Do you guys use the collets on 850s with the Norvilbronze nuts?

Yes I do, they stick out more than on a 750 but do not come loose. Not sure mine are Norvil but they are bronze, would never buy anything from the bearded one on principle but I bought mine 2nd hand 25 years ago.

 

[bchessell2]

They are norvil bronze ones I recommend.Also putting on new header pipes without the crossover gives you more thread. The 850s with the crossover were the ones to originally show up with stripped threads because of the crossover.The split collars took more thread away.The more thread the better.
Cheers
Bruce

 

[jimbo]

heres bad nut(under sized threads) and good nut(correct sized threads) videos, the morals of the story are,
repair,replace,insert the threads to standard correct dimensions
ensure you have standard correct thread sizes on you nuts( probably not a good idea to make some kind of sized threads in your head then make some nuts to fit that are whatever?)

https://www.youtube.com/watch?v=HHhQSON ... detailpage


https://www.youtube.com/watch?v=stxy25I ... detailpage

 

[gortnipper]

heres bad nut(under sized threads) and good nut(correct sized threads) videos, the morals of the story are,
repair,replace,insert the threads to standard correct dimensions
ensure you have standard correct thread sizes on you nuts( probably not a good idea to make some kind of sized threads in your head then make some nuts to fit that are whatever?)

https://www.youtube.com/watch?v=HHhQSON ... detailpage


https://www.youtube.com/watch?v=stxy25I ... detailpage

Yes, if I was doing it now I would get the comnoz inserts done. But, as I had the head repaired about 25 years ago, and my friend is an aircraft toolmaker he offered to do the work gratis. He machined out the old ports and created billet AL inserts, which he pressed in. Both had a chamfer, and they were heli-arc welded in by Dewey's and then he cut the threads.

As there was no internet then, and I; a) didnt know any better, and b) didnt know I had the likely orgiinal 850 nuts buried at the bottom of a large coffee tin full of nuts and bolts, I just followed his lead and he cut the threads for the D12/167 nuts.

As Dave says, hopefully my machinist did a good guess on his numbers. Else, I use the old nuts!

 

[jimbo]

Yes, if I was doing it now I would get the comnoz inserts done. But, as I had the head repaired about 25 years ago, and my friend is an aircraft toolmaker he offered to do the work gratis. He machined out the old ports and created billet AL inserts, which he pressed in. Both had a chamfer, and they were heli-arc welded in by Dewey's and then he cut the threads.

As there was no internet then, and I; a) didnt know any better, and b) didnt know I had the likely orgiinal 850 nuts buried at the bottom of a large coffee tin full of nuts and bolts, I just followed his lead and he cut the threads for the D12/167 nuts.

As Dave says, hopefully my machinist did a good guess on his numbers. Else, I use the old nuts!

sounds like you did the right thing at the time, I was referring more for work likely to be done in the future