Pete Lewis Posted October 6, 2019 Report Share Posted October 6, 2019 none are shown in the hardware book but all these threads were used at some time on something standard/triumph NF NC GAS UNF UNC BFS are all thats in there and if a 3/8 ntpt x18 tap fits the sump thats what you need Pete Link to comment Share on other sites More sharing options...
Ben Caswell Posted October 6, 2019 Report Share Posted October 6, 2019 16 hours ago, KevinR said: Next time I need a magnetic one I'll get a magnet and drill a hole in an old plug - certainly wouldn't trust the one from Quillers. My Marlin has been running around for over thirty years with a Scalextric motor magnet Araldited to the original sump plug. Link to comment Share on other sites More sharing options...
Pete Lewis Posted October 6, 2019 Report Share Posted October 6, 2019 next time you scrap a loud speaker, cut the magnet off and let it attach to the side or bottom of the sump pete Link to comment Share on other sites More sharing options...
Colin Lindsay Posted October 6, 2019 Report Share Posted October 6, 2019 1 hour ago, Pete Lewis said: next time you scrap a loud speaker, cut the magnet off and let it attach to the side or bottom of the sump pete Attach it to the oil filter; that way all of the metal debris ends up inside the filter and can be thrown away when it's changed. Link to comment Share on other sites More sharing options...
Badwolf Posted October 6, 2019 Report Share Posted October 6, 2019 8 hours ago, Pete Lewis said: the above charts give all the relevant sizes the major diameters all relate back to the pipe internal and external diameters all dream up by someone with a sense of humour !! pete I just wondered what the relationship was between the 'size' (3/8) and the actual diameter of the thread. Link to comment Share on other sites More sharing options...
KevinR Posted October 6, 2019 Report Share Posted October 6, 2019 On 05/10/2019 at 14:58, Badwolf said: The external diameter of the Fb one on the first thread is 0.592inches the last thread is 0.668inches the thread length is 0.475inches Counting the threads on the plug shown in the photo and using the measured thread lengths shows that there are 19 threads per inch, which makes it a BSP thread, not NPT. Link to comment Share on other sites More sharing options...
Pete Lewis Posted October 6, 2019 Report Share Posted October 6, 2019 Ive not looked up but its the outside threaded diameter of a 3/8" bore steel walled pipe of a std wall thickness Hence these threads bears little resemblance to the pipe bore size but is used Some ome can explain it in gobblede goop,for us Pete Link to comment Share on other sites More sharing options...
Gadgetman Posted October 8, 2019 Author Report Share Posted October 8, 2019 On 06/10/2019 at 12:23, Vanadium23 said: - I am not an engineer, ready to be advised if wrong, but my basic understanding is that old Mr Joseph Whitworth in the mid 19C gave us the Whitworth thread based on a 55 degree pitch and radiused “ trough” The British Standard Pipe thread = BSP is based on that. In 2 forms: - a parallel thread “British Standard Pipe Parallel” =BSPP -a tapered thread “British Standard Pipe Tapered” = BSPT However, In North America, a different system was adopted based on a 60 degree pitch and sharp “troughs” ( not the right engineering term,I know) This was, and still is their “imperial i.e. non- metric standard, for pipe threads. This is “National Pipe Thread” = NPT. Being a taper thread, the T is also taken as being Tapered. In addition to North America, tap and die sets, from elsewhere- from Taiwan for example, will have the American NPT taps, not BSP. 1.I can’t think British cars were ever been equipped with NPT threads, They will have been BSP - whether parallel or tapered. I.BSP and NTP are not compatible, though probably can be “made “ to fit. ( look at Pete’s charts ) 2.A taper thread is designed so that as it is tightened until the the threads start to seal against each other - without the use of a sealing washer, tape or anything, and this should be achievable with very little torque. 3.A parallel thread set up needs a sealing washer of some sort or something to seal the threads as there isn’t the thread -sealing of the taper system. What you need is old Joe Whitworth’s British BSP .... not NTP! Thanks for this but Why does an 3/8 NPT tap screw straight into the sump and gearbox plug holes? Link to comment Share on other sites More sharing options...
Pete Lewis Posted October 8, 2019 Report Share Posted October 8, 2019 Why , Because that is what it is Who knows the idiosyncrasies of the triumph design engineers There is enough it dont fit on here to show common used BSP will go thread bound 18 in 19 tpi wont go Pete Link to comment Share on other sites More sharing options...
Unkel Kunkel Posted October 8, 2019 Report Share Posted October 8, 2019 5 hours ago, Gadgetman said: Thanks for this but Why does an 3/8 NPT tap screw straight into the sump and gearbox plug holes? I don’t know. I must confess. I work at a basic level - something either fits or it doesn’t. If it fits - and I means it threads easily and is stable with finger tightening, that is good -and as probably good as it is going to get.If you’re reaching for a big spanner and using a vice - stop kidding yourself. So basic, that some of the bits I will try for a good fit come from jars and boxes of loads of nuts and bolts taken from long-forgotten, dismantled “things”. I do have thread gauges and do use them but just trying a dozen or so will usually result in a good match. This method is not so much UNC, Metric or BSW, UNC but more ADT. Any Damn Thing . 1 Link to comment Share on other sites More sharing options...
KevinR Posted October 9, 2019 Report Share Posted October 9, 2019 The bottom line is simple..... For reasons only known to the Standard Triumph designers, they decided to use a 3/8" NPT thread for the sump plugs and drain plugs across the Triumph range of the day. I would hazard a guess that it was cheaper to buy millions of 3/8" NPT plugs than 3/8" BSP plugs - in the quantities involved, fractions of a penny make a difference ! Tapping the hole in the sump, gearbox or diff housings would cost exactly the same regardless of whether it was NPT or BSP. Link to comment Share on other sites More sharing options...
Pete Lewis Posted October 9, 2019 Report Share Posted October 9, 2019 ADT a sort of lucky dip ??? i have everything that fits nothing and nothing that fits everything all in 36 x 4 ltr marg tubs from my mum all labeled and have lasted years in lucky dip sydrome a draw full of taps where the etched size has long departed ...down from 1 1/4 " to 12ba i dont have a 3/8npt though they take some adt !!!! Pete Link to comment Share on other sites More sharing options...
Gadgetman Posted October 9, 2019 Author Report Share Posted October 9, 2019 Ha ha. I know that feeling. I’ve a NPT magnetic plug coming now.... anyone want a BSP one, I’ve a few spares!!! I’ll be glad once this spare engine is in the car.... once i’ve got the sump plug I can prime the oil system and check the oil Pressure before fitting. Carbs are nearly Finished, just trying to find damper weights as the set I’ve got came off a 2ltr with damper springs. I managed to adapt new linkage springs to fit and turned up bushes to support them on the body. 3 years and nearly finished!! ( then on to re-building the spare overdrive gearbox!) the wife said she would only let me buy this car if it wasn’t taken to bits to restore....she never said anything about buying spares to rebuild and transplant into the car... 😂 Link to comment Share on other sites More sharing options...
Dave1360 Posted October 9, 2019 Report Share Posted October 9, 2019 The heavier damper weights are available from Burlen at http://zenithcarb.co.uk/diaphragm-retaining-washer.html, part number B17243. I spent several years scanning eBay to find a pair of weights, only to discover they can be bought new. It's also well worth getting their catalogue at http://zenithcarb.co.uk/books-catalogues/zenith-cd-catalogue.html for the cost of postage alone. Link to comment Share on other sites More sharing options...
Pete Lewis Posted October 9, 2019 Report Share Posted October 9, 2019 i guess you can use a spring and thin weight but never a spring and a heavy makes it very rich (unless it is specified ) i tried springs in my rorty 1600 but Nah didnt work well. . Pete Link to comment Share on other sites More sharing options...
Paulfc Posted June 22, 2020 Report Share Posted June 22, 2020 Hi, Having just successfully (after much fun and games) removed both the sump plug and gearbox filler plug I would like to replace them with new if I can. I intend to have hex nuts welded onto what remains of the once square heads as an interim solution and I appreciate they don’t need to torqued “to death”. My simple question is this, is is still possible to buy new replacement plugs with the correct NPT thread? If it is, can someone tell me where please? Many thanks, Paul Link to comment Share on other sites More sharing options...
Paul H Posted June 22, 2020 Report Share Posted June 22, 2020 7 minutes ago, Paulfc said: Hi, Having just successfully (after much fun and games) removed both the sump plug and gearbox filler plug I would like to replace them with new if I can. I intend to have hex nuts welded onto what remains of the once square heads as an interim solution and I appreciate they don’t need to torqued “to death”. My simple question is this, is is still possible to buy new replacement plugs with the correct NPT thread? If it is, can someone tell me where please? Many thanks, Paul Try Canleys https://www.canleyclassics.com/?diagram=triumph-spitfire-mkiv/1500-engine-plates-and-sump&ptno=ULC1998 The nut is 24mm and has a copper washer Paul Link to comment Share on other sites More sharing options...
Paulfc Posted June 22, 2020 Report Share Posted June 22, 2020 Thanks Paul, As I understand it, if the plug has a washer it won’t be NPT. A tapered thread would not require one. Paul 1 Link to comment Share on other sites More sharing options...
Paul H Posted June 22, 2020 Report Share Posted June 22, 2020 1 minute ago, Paulfc said: Thanks Paul, As I understand it, if the plug has a washer it won’t be NPT. A tapered thread would not require one. Paul My Vitesse has a tapered square end on the sump and diff filler and I’ve replaced both with the Canleys 24mm magnetic plug . Paul Link to comment Share on other sites More sharing options...
Paulfc Posted June 22, 2020 Report Share Posted June 22, 2020 OK, thanks. So does it go fully into the sump and the washer compress. P. Link to comment Share on other sites More sharing options...
Paul H Posted June 22, 2020 Report Share Posted June 22, 2020 4 minutes ago, Paulfc said: OK, thanks. So does it go fully into the sump and the washer compress. P. Yes , plug goes fully home Paul Link to comment Share on other sites More sharing options...
Paulfc Posted June 22, 2020 Report Share Posted June 22, 2020 Thank you. Link to comment Share on other sites More sharing options...
Peter Truman Posted June 23, 2020 Report Share Posted June 23, 2020 If there is any doubt I can confirm that the Triumph GT6, Vitesse and Herald, Spitfire uses a 3/8in 18tpi NPT thread, I've just run a 3/8in NPT tap into a spare GT6 sump & Spit 1500 and it fits like a glove, I also used an imperial thread gauge and the plug (tapered) is 18tpi. Why do I have a 3/8in NPT tap you ask, because the thermo switch I brought to control the elect rad fan on the daughters Spit Mk2 was 3/8in NPT, but it came with a 1/2in BSP brass adapter boss as well, which was to big to fit in the 134681 thermostat cover I fitted the thermo switch into. The 3/8 inch NPT tap & drill was less than $15 delivered ex China vs >$100 tap only local supply, Now seeing this discussion (thread, Oh!) and the confirmation that Triumphs used 3/8in NPT sump plugs on the engine, gearbox and diff, its time for me to upgrade the diff drain plugs on the Spit and Vitesse from the 7/16 UNF largest tap I had at the time to the Triumph standard 3/8in NPT so I can use the std sump plug. who would have thought Triumph used a NPT thread? Link to comment Share on other sites More sharing options...
Paulfc Posted June 23, 2020 Report Share Posted June 23, 2020 Peter, I believe the TR6 (maybe other TRs too) use the NTP tapered thread too. Paul Link to comment Share on other sites More sharing options...
Paulfc Posted June 23, 2020 Report Share Posted June 23, 2020 NPT not NTP. Link to comment Share on other sites More sharing options...
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