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Exhaust manifold studs and brass nuts


Colin Lindsay

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The Spalding ones that have just arrived today are 1 3/4"; quite long compared to the ones I've just binned which were 1 1/4". They're UNF so I can use nuts to fit them into the manifold, but the only worry is that the unthreaded 'saddle' in the middle is quite long - longer than the thickness of gasket and exhaust flange which may cause problems on tightening. If needs be I can keep them for any 6-cylinder that may need some and buy shorter, but they arrived in two days so fast delivery. I'll experiment and report back.

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So the debate rolls on..

Out of curiosity, I did a check of exhaust manifold nuts with three major Triumph suppliers. They all list brass nuts for exhaust manifolds. Back in the day I recall going into the local BL dealer and getting the same, as listed for the exhaust manifold. 

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The Spalding Fasteners versions took a UNF nut from my stock on both ends, and screwed into the Herald manifold first time - this is the exhaust fastening stud, not the carbs. With the gasket and exhaust flange fitted there's about 1/8 of saddle visible, but using a spring washer covers that sufficiently to tighten the nut down. On Heralds at least they'd need to be nearly 3 inches or more to cause any problems ie they would foul the block.

The eBay Triumph-Supplier version was so soft the stud puller flattened the threads and ate into the metal while I tightened them into the manifold (not even a scratch on the Spalding versions), and the nuts weren't much better and stripped on first use.

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1 hour ago, trigolf said:

So the debate rolls on..

Out of curiosity, I did a check of exhaust manifold nuts with three major Triumph suppliers. They all list brass nuts for exhaust manifolds. Back in the day I recall going into the local BL dealer and getting the same, as listed for the exhaust manifold. 

There is a lot of confusion in that people use the Overall "definition" of anything "brassy" as BRASS (copper and zinc). Brass is a soft(er) metal. Bronze ( Copper and Tin) is generally regarded as "Harder" and more suitable for structural needs.  "brass" Nuts will distort more than Bronze.

Pete

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Studs that fit into aluminium casings are usually UNC, to give a stronger hold into the relatively soft metal,  with a UNF end onto which the steel nut is fitted.  If the stud fits into a steel casing, it is usually UNF at both ends.

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On 26/04/2021 at 17:14, Badwolf said:

Phew, that's a relief. I hate recommending places that turn out to be cr*p.

Excellent to deal with; their order last week was excellent, but on surfing their site I thought I'd try the double-length brass nuts for the benefit of the extra thread and grip; they arrived within 24 hours but won't fit the studs - a quick check revealed they're not UNF. I spoke to Spalding who tell me they've had numerous complaints about this issue and it appears someone has incorrectly labelled an entire production and put it into the wrong parts bin. Not only is it refreshing to see someone admitting to a problem but they're also sending out replacements first with a returns envelope included. Definitely good service.

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Hmm  I'm now not so sure about Spalding - Paid for an order a few days ago now and heard nothing - sent mails and  tried calling  - always engaged.... NO RESPONSE  Order was only £11 but even so....

 

 

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