AlanT Posted July 18, 2022 Report Share Posted July 18, 2022 Hi, I’m sure there are endless threads on replacing exhaust manifold studs. Rather than start another please can someone can point me in their direction as my ‘bodge’ fix is a bit leaky. Can’t get the forum search function to work for me today! Thanks Alan Link to comment Share on other sites More sharing options...
Clive Posted July 18, 2022 Report Share Posted July 18, 2022 It can be as simple as the old studs unscrewinging, and fitting the new ones (though making sure the flange surfaces are flat, and filing to make it so, highly recommended. ) However, the studs can/often break. Giving them a few medium weight taps with a hammer can help things, as can heat. If yo have a welder, make use of it and weld a nut to the stud near the flange, that will heat the stud nicely to red heat, and give you something to get a spanner on. If the studs do break, you will need to drill them out, which needs care. Or drill and retap 3/8UNC or even M10, and use cap head setscrews.... (this applies to spitfire/herald) Thats my 2p worth. Link to comment Share on other sites More sharing options...
AlanT Posted July 19, 2022 Author Report Share Posted July 19, 2022 Thanks @clive I do have a welder and will do exactly as you suggest! Link to comment Share on other sites More sharing options...
Clive Posted July 19, 2022 Report Share Posted July 19, 2022 36 minutes ago, AlanT said: Thanks @clive I do have a welder and will do exactly as you suggest! As always, no guarantees. On my last 1500 engine, I solved repeated gasket blowing by filing the mating surfaces flat and making sure they fitted together a well as I could manage. Amazing how poor the surfaces were, and explained why gaskets kept failng. I also went down the M10 route, but I suspect new studs and the extra long brass nuts would have sufficed. Link to comment Share on other sites More sharing options...
AlanT Posted July 19, 2022 Author Report Share Posted July 19, 2022 26 minutes ago, clive said: As always, no guarantees. On my last 1500 engine, I solved repeated gasket blowing by filing the mating surfaces flat and making sure they fitted together a well as I could manage. Amazing how poor the surfaces were, and explained why gaskets kept failng. I also went down the M10 route, but I suspect new studs and the extra long brass nuts would have sufficed. You may be right about the surfaces. I’d forgotten about this 1500 foible after 30 years but it only took a few hundred miles to remind me! Not A full blow at the moment but once they start… Link to comment Share on other sites More sharing options...
johny Posted July 19, 2022 Report Share Posted July 19, 2022 Yes nothing for it but to replace the gasket once blown. However after I had repeated failures on my Mk1 Vitesse Ive found retightening the fixings regularly has stopped this as they just seem to loosen off with use.... 1 Link to comment Share on other sites More sharing options...
chrishawley Posted July 19, 2022 Report Share Posted July 19, 2022 11 hours ago, AlanT said: exhaust manifold studs To clarify: Is that referring to the 3 studs exhaust manifold to downpipe, rather that cylinder head to exhuast manifold studs? On a Spitfire 1500? An embeliishment to the welded nut technique: If such a nut is lightly welded then the weld may yield before the thread does. Using MIG, weld as deeply and melty-inny as possible with max possible current and min possible wire. Then allow to fully, gradually, cool in air before spannering. The Achilles heel of the S1500 downpipe is the bracket that stabilises the downpipe to the right lowest stud on the gearbox. In particular the absence thereof. If missing then creating a suitable arrangement vastly improves the longevity of the manifold to downpipe joint. 1 Link to comment Share on other sites More sharing options...
AlanT Posted July 19, 2022 Author Report Share Posted July 19, 2022 It’s the downpipe @chrishawley thanks for the tip Link to comment Share on other sites More sharing options...
JohnD Posted July 19, 2022 Report Share Posted July 19, 2022 If I may in addition to the above: Weld a nut to the stud, but then when cool apply a thread penetrant, not WD40! When trying to turn the old stud out, tighten it first! The go for to-and-fro motion until a whole rotation is possible. While taking it out, if it starts to 'squeal', stop! Reverse, more oil, to-and-fro. The squeal can mean that the stud is about to seize and break! Brass nuts? Brass is far too soft a metal. You need bronze! Available online of it you are near a coast from a chandlers. John 1 Link to comment Share on other sites More sharing options...
Morgana Posted October 23, 2023 Report Share Posted October 23, 2023 (edited) I had read the very same thing, JohnD, and have hunted for bronze nuts high and low, with nary a result (and that's in Cornwall!) There don't seem to be any online suppliers outside the US, and all the 'usual suspects' sell brass nuts. I've just replaced mine as the ones on there appeared to be a totally different thread from the studs and the gasket had gone, and was very wary of doing them up as they felt very soft. I just nipped them with the engine running until I couldn't feel any blow-by with my hand... Maybe I need to make some bronze ones. My bracket is missing (Herald 1200 Canley 122134 and GEX7511). The former is NCA, but I guess I could lash up an exhaust clamp or something. Does GEX7511, the twisted piece, bolt onto the bell housing flange somewhere, or further back? Edited October 24, 2023 by Morgana Link to comment Share on other sites More sharing options...
Colin Lindsay Posted October 24, 2023 Report Share Posted October 24, 2023 I think GEX7511 bolts onto the rear of the gearbox using one of the two lower bolts; if I'm correct about the part I have them fitted this way on Heralds, and the exhaust clamp then attaches to that. 1 Link to comment Share on other sites More sharing options...
Morgana Posted October 24, 2023 Report Share Posted October 24, 2023 Thank you Colin. Do you have a picture? I found a thread from you while searching around that involved a peculiar exhaust-sized clamp. Is that some kind of similar support bracket? As the original P-shaped things in the diagram aren't available, I wonder if I'll have to make a suitable strap to fit a U-clamp or similar current exhaust fitting. Link to comment Share on other sites More sharing options...
Colin Lindsay Posted October 24, 2023 Report Share Posted October 24, 2023 The exhaust clamps are readily available from any good Motor Factors, you just need the diameter of your exhaust. As it's only to support it and not seal a joint an approximate size will do. Once it's tightened up then the metal bracket from the rear of the gearbox goes over the uppermost 'leg' and bolts to that. I've found that if your exhaust is tight to the chassis then the top hose bracket from the front suspension, the one off the suspension turret, is a nicely 90-degrees twisted metal bracket and will hold it nicely. These are old photos, ignore the oil leaks which have long been sorted, and yes that bolt on the red one has been screwed in properly too. 1 Link to comment Share on other sites More sharing options...
JohnD Posted October 25, 2023 Report Share Posted October 25, 2023 (edited) On 23/10/2023 at 23:43, Morgana said: I had read the very same thing, JohnD, and have hunted for bronze nuts high and low, with nary a result (and that's in Cornwall!) There don't seem to be any online suppliers outside the US, and all the 'usual suspects' sell brass nuts. Yes! US only! I wonder why? But a quick Google finds this supplier in UK: Marine Fasteners - Anglia Stainless LTD ("Stainless" but they do non-ferrous too!) There will be others, look for a chandler near you. Chandlers in Cornwall (boatchandlersguide.com) John Edited October 25, 2023 by JohnD 1 Link to comment Share on other sites More sharing options...
Pete Lewis Posted October 25, 2023 Report Share Posted October 25, 2023 dont see the problem canley list brass nuts for the exhaust been used for 50 years and at 56p whats the problem Link to comment Share on other sites More sharing options...
JohnD Posted October 25, 2023 Report Share Posted October 25, 2023 (edited) The problem? THEY'RE BRASS! Compared to Bronze, Brass is malleable, it will strip the thread more easily, has a lower melting point, so will soften more easily in a high temp application and is much more prone to corrosion. Brass is an inferior alloy, pretty but that's it. John Edited October 25, 2023 by JohnD 1 Link to comment Share on other sites More sharing options...
Colin Lindsay Posted October 25, 2023 Report Share Posted October 25, 2023 55 minutes ago, JohnD said: The problem? THEY'RE BRASS! Compared to Bronze, Brass is malleable, it will strip the thread more easily, has a lower melting point, so will soften more easily in a high temp application and is much more prone to corrosion. Brass is an inferior alloy, pretty but that's it. John True, the ones I bought from a prolific eBay seller form my 13/60 stripped the threads almost instantaneously. Swiss Cheesium! I was able to buy bronze versions both in standard size but also in extra long which grip more threads. Spalding Fasteners sell a range of far better quality brass nuts than many other suppliers, I've used those too, and they also sell the extra long versions. HOWEVER: as the studs in another manifold were badly stripped I removed them completely, drilled out the rusty manifold and used standard UNF bolts and nuts of the same size. I reckon the car will get limited use compared to past years, and if the exhaust ever needs replacing I'll just cut the nuts off and replace both bolts and nuts. 1 Link to comment Share on other sites More sharing options...
PeteH Posted October 25, 2023 Report Share Posted October 25, 2023 Try Googling Silicon Bronze. Greater Tensile strength than straight brass. Pete Link to comment Share on other sites More sharing options...
Morgana Posted October 25, 2023 Report Share Posted October 25, 2023 It's not the material that's the problem, PeteH, it's that the bronze nuts aren't obtainable! I think I remember the manual specifying bronze nuts, yet I guess cost means all the current kits supply brass as at least it doesn't weld to the steel studs with all the temperature cycling. I've tried all the chandlers I know, JohnD (I do a lot of sailing so am familiar with quite a few) and those that have bronze fittings are almost exclusively metric so I've had no luck. The same with Imperial clevis pins. There are fewer and fewer treasure-trove type chandlers, and more with high-tech dealer-specific parts rather than generic, good quality hardware. I've enquired with Anglia Stainless just now so I'll see what they come up with. Brilliant photos Colin, thank you. I have a big wire loop of various exhaust clamps of that same design, so I'm sure I can work up a metal strip to hook over one of the threads. A good spot on the nuts, too. I had wondered about barrel nuts since there are more threads, but as I understand the tension in a threaded joint is entirely in the first three threads I wonder whether they can actually be torqued more before stripping than normal height brass nuts? 1/2" bronze hex is readily available. Perhaps I ought to manufacture a sideline in 5/16" UNF bronze barrel nuts... Link to comment Share on other sites More sharing options...
JohnD Posted October 25, 2023 Report Share Posted October 25, 2023 (edited) Morgana, sorry to hear that! Hope Anglia can help. If not, it's a long way to order from, but at least the US will have no truck with this new fangled 'motric' business! Plenty there. Edited October 25, 2023 by JohnD Link to comment Share on other sites More sharing options...
Puglet1 Posted November 28, 2023 Report Share Posted November 28, 2023 On 25/10/2023 at 20:33, Morgana said: It's not the material that's the problem, PeteH, it's that the bronze nuts aren't obtainable! I think I remember the manual specifying bronze nuts, yet I guess cost means all the current kits supply brass as at least it doesn't weld to the steel studs with all the temperature cycling. I've tried all the chandlers I know, JohnD (I do a lot of sailing so am familiar with quite a few) and those that have bronze fittings are almost exclusively metric so I've had no luck. The same with Imperial clevis pins. There are fewer and fewer treasure-trove type chandlers, and more with high-tech dealer-specific parts rather than generic, good quality hardware. I've enquired with Anglia Stainless just now so I'll see what they come up with. Brilliant photos Colin, thank you. I have a big wire loop of various exhaust clamps of that same design, so I'm sure I can work up a metal strip to hook over one of the threads. A good spot on the nuts, too. I had wondered about barrel nuts since there are more threads, but as I understand the tension in a threaded joint is entirely in the first three threads I wonder whether they can actually be torqued more before stripping than normal height brass nuts? 1/2" bronze hex is readily available. Perhaps I ought to manufacture a sideline in 5/16" UNF bronze barrel nuts... Hi Morgana. Were you able to obtain the 5/16 UNF nuts in bronze? Link to comment Share on other sites More sharing options...
Morgana Posted November 30, 2023 Report Share Posted November 30, 2023 Alas, no. Instead I have a bar of 1/2" bronze hex and as soon as my lathist has recovered from Covid I'll set about making some with him... Link to comment Share on other sites More sharing options...
Mjit Posted November 30, 2023 Report Share Posted November 30, 2023 Some on eBay ATM - though at £42.24 (+p&p) for 16. Link to comment Share on other sites More sharing options...
JohnD Posted November 30, 2023 Report Share Posted November 30, 2023 Look for Bronze nuts 5/16" imperial : Silicon Bronze Nuts (UNC thread) (arthurbeale.co.uk) 50p each. John Link to comment Share on other sites More sharing options...
KevinR Posted November 30, 2023 Report Share Posted November 30, 2023 1 hour ago, JohnD said: Look for Bronze nuts 5/16" imperial : Silicon Bronze Nuts (UNC thread) (arthurbeale.co.uk) 50p each. John John, I think that the challenge is to get 5/16" UNF bronze nut, rather than UNC. Having said that, it may actually be easier to get some 5/16" studs with a UNC thread on both ends. Link to comment Share on other sites More sharing options...
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