Mad4classics Posted June 23, 2020 Report Share Posted June 23, 2020 18 hours 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 I'm also puzzled by Canleys' offering; there's no picture on their web site to show what it's about. Taper threads seal by an interference fit which is achieved just beyond the "finger tight" point along the whole length of thread engagement. (This is why a BSP plug in NPT doesn't seal properly because the threads bind at certain point along the engagement length therefore not forming a proper interference fit seal.) Straight threads do need a sealing washer - mixing straight and taper threads is unusual! David Link to comment Share on other sites More sharing options...
Paul H Posted June 23, 2020 Report Share Posted June 23, 2020 2 minutes ago, Mad4classics said: I'm puzzled by Canleys' offering; there's no picture on their web site to show what it's about. Taper threads seal by an interference fit which is achieved just beyond the "finger tight" point along the whole length of thread engagement. (This is why a BSP plug in NPT doesn't seal properly because the threads bind at certain point along the engagement length therefore not forming a proper interference fit seal.) Straight threads do need a sealing washer - mixing straight and taper threads is unusual! David I’ve got the Canley sump plug with copper washer on both sump and diff filler and they thread on very easily then I just nip up . I’ll be checking the diff oil level soon . Do you want a pic ? Paul Link to comment Share on other sites More sharing options...
Mad4classics Posted June 23, 2020 Report Share Posted June 23, 2020 Paul, Is the thread straight NPS (non self sealing) or taper NPT (self sealing)? Got my last lot of plugs from ANG Classic Car Parts plus a few spare and the fit a treat; but I notice their website picture of the plug has changed so presumably a new supplier? Hope they fit as well as before. Taper threads do not need to be gorilla tight to seal. David Link to comment Share on other sites More sharing options...
Paul H Posted June 23, 2020 Report Share Posted June 23, 2020 1 hour ago, Mad4classics said: Paul, Is the thread straight NPS (non self sealing) or taper NPT (self sealing)? Got my last lot of plugs from ANG Classic Car Parts plus a few spare and the fit a treat; but I notice their website picture of the plug has changed so presumably a new supplier? Hope they fit as well as before. Taper threads do not need to be gorilla tight to seal. David Straight thread plus flat copper washer Paul Link to comment Share on other sites More sharing options...
DanMi Posted June 23, 2020 Report Share Posted June 23, 2020 It is the plug which is tapered not the thread in the sump, so the Canley's straight plug with washer fits in the straight thread. The original (at least post mid 1966) plug is tapered so is an interference fit. Link to comment Share on other sites More sharing options...
Pete Lewis Posted June 23, 2020 Report Share Posted June 23, 2020 its generally.......... down to the manufacture process the hole is parallel the plug is tapered its much easier to make . a hex headed plug with a straight thread needs a crushable washer and a sump/casting face thats machined flat to seal against the threads wont seal by themselves Pete Link to comment Share on other sites More sharing options...
Nick Jones Posted June 23, 2020 Report Share Posted June 23, 2020 Properly speaking, both hole and plug should be tapered, otherwise the contact area for sealing will be short. BSP threads can be tapered (BSPT) or parallel (BSPP) with the latter also sometimes being referred to as gas threads (G1/4 is 1/4”BSPP) Nick Link to comment Share on other sites More sharing options...
NonMember Posted June 23, 2020 Report Share Posted June 23, 2020 I have a magnetic sump plug - straight thread and copper washer - bought from a reputable supplier, which absolutely does not fit. It's slightly too large a thread for the sump. I gave up and put a tapered one back in. Link to comment Share on other sites More sharing options...
Peter Truman Posted June 23, 2020 Report Share Posted June 23, 2020 The 3/8 in NPT tap I have Is a taper as are the original Triumph plugs that I have, as per Nicks advice The original Triumph sump plug when locked has around 2 To 3 full threads left protruding on the outside, but I suppose that depends how far the taper tap is run in. Link to comment Share on other sites More sharing options...
Mad4classics Posted June 23, 2020 Report Share Posted June 23, 2020 1 hour ago, Pete Lewis said: the threads wont seal by themselves Pete NPT threads (both male and female being NPT) are classed self sealing but are not pressure rated without sealing in some way, therefore ok for sump plugs and the like. Some classes of NPTF (F for Fuel) are completly self sealing because they form a complete interference fit and therefore do not need any sealant. David Link to comment Share on other sites More sharing options...
Badwolf Posted June 23, 2020 Report Share Posted June 23, 2020 52 minutes ago, NonMember said: I have a magnetic sump plug - straight thread and copper washer - bought from a reputable supplier, which absolutely does not fit. It's slightly too large a thread for the sump. I gave up and put a tapered one back in. Welcome to my world (seepage 1) Link to comment Share on other sites More sharing options...
Pete Lewis Posted June 23, 2020 Report Share Posted June 23, 2020 i did say straight threads , most of the aftermarket hex heads seem to be straight not a NPT or anything like it pete Link to comment Share on other sites More sharing options...
Mad4classics Posted June 24, 2020 Report Share Posted June 24, 2020 12 hours ago, Pete Lewis said: i did say straight threads , most of the aftermarket hex heads seem to be straight not a NPT or anything like it pete OK, sorry - with you now. Your quite right there's a right mix of plugs being sold, some don't fit. The female filler and drain threads I've got are all appear tapered; could be deformation caused by years of taper plug fitting maybe? - but I would hope not. The ASME standard recommends both sides taper. Or is this another case of Triumph bean counters? Putting a straight plug with a sealing washer in a tapered hole results in the thread fit changing progressivly along the engagement length. David Link to comment Share on other sites More sharing options...
Colin Lindsay Posted June 24, 2020 Report Share Posted June 24, 2020 16 hours ago, Pete Lewis said: its generally.......... down to the manufacture process the hole is parallel the plug is tapered its much easier to make . That's the way I always took it to be, the hole is just a straight-through tapped drilling - try it with a normal bolt which you'll know isn't tapered - and the plugs are tapered. Sump, gearbox and diff are all straight-through. Link to comment Share on other sites More sharing options...
Paulfc Posted June 24, 2020 Report Share Posted June 24, 2020 On 06/10/2019 at 16:03, Colin Lindsay said: 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. Colin, Please excuse if this seems a daft question, attach it how? Surely not externally so do you drop a small magnet into the filter? If not external I won’t be doing anything with it for a while as I’ve just changed the oil after the devil's own job of getting the plugs out. The PO I assume was not aware of the concept of “nipping” the plug tight and obviously opted for a two foot extension to make sure it was in really tight and made round at the same time. Never a dull moment with a Triumph! Thanks, Paul Link to comment Share on other sites More sharing options...
NonMember Posted June 24, 2020 Report Share Posted June 24, 2020 21 minutes ago, Paulfc said: Please excuse if this seems a daft question, attach it how? Surely not externally so do you drop a small magnet into the filter? There are no daft questions! The objective of the magnet is to encourage the swarf to "step aside" rather than circulating. For that, you only need a magnetic field. The oil filter canister is thin and probably steel, so it won't interfere with magnetic fields. Just clamp a magnet to the side of the filter. If you can find a ring magnet that slides over it then you're on a winner. Otherwise, a bunch of thin plate magnets sown into a strip of knicker elastic, and just wrap it round the filter. When you next change the filter, just transfer the magnet(s) over - the crud is still inside the filter so the magnets are clean (or as clean as anything under the bonnet can be). That said, the oil in the filter has already passed through the pump and is moving at a fair lick. The magnet will be much less effective there than it would be in the sump. You will need a more powerful magnet. Link to comment Share on other sites More sharing options...
Colin Lindsay Posted June 24, 2020 Report Share Posted June 24, 2020 What he said, up there!! You can actually buy professionally made magnet bands that wrap round the filter, but a good quality magnet from an old speaker, securely taped to the outside, will catch a lot of stuff, even when the engine stops. Try one, run it for a bit, then remove the filter and cut it open - you'll be amazed at what's stuck to the face where the magnet is. This link is to one manufacturer of specially-made magnets but expensive!! https://synlube.com/magnets.htm And beware the junk about improving fuel economy on some on-line sellers sites; I doubt if a magnetic field will improve engine efficiency... Link to comment Share on other sites More sharing options...
JohnD Posted June 24, 2020 Report Share Posted June 24, 2020 Why use a magnet? Its a FILTER! Oil filters typically have a pore size of les than 10 MICRONS, that's 0.01mm. Anything that gets through is dust. Use one on the diff plug, drain or fill, as there is no filter there, and the gearbox, ditto. John Link to comment Share on other sites More sharing options...
Paulfc Posted June 24, 2020 Report Share Posted June 24, 2020 Thanks all! One final question, hopefully, on this topic. Where can I buy a good quality square head socket/spanner? The diff. plug is pristine and I’d, ideally, like to keep it that way. Ive done a search but couldn’t identify anything that seemed appropriate. Thanks. Link to comment Share on other sites More sharing options...
Roger Posted June 24, 2020 Report Share Posted June 24, 2020 19 minutes ago, JohnD said: Why use a magnet? Its a FILTER! The magnet can not have any detrimental impact on the filter performance that I can think of (?). No harm done by using one. And it will catch a lot of those ”dust metal particles” (less than 0,01 mm) that otherwise would pass the filter. Ten microns is certainly not much, but metal particles in the oil will never improve the durability of an engine no matter how small they are. Ten microns is indeed a small particle, but if you have fifty billion particles all less than 0,01 mm in the oil sump then they too becomes a problem. Link to comment Share on other sites More sharing options...
Colin Lindsay Posted June 24, 2020 Report Share Posted June 24, 2020 Belt and braces. It can't hurt, and may even help. Link to comment Share on other sites More sharing options...
KevinR Posted June 24, 2020 Report Share Posted June 24, 2020 3 hours ago, Paulfc said: Thanks all! One final question, hopefully, on this topic. Where can I buy a good quality square head socket/spanner? The diff. plug is pristine and I’d, ideally, like to keep it that way. Ive done a search but couldn’t identify anything that seemed appropriate. Thanks. https://shop.snapon.com/categories/Double-Square%2C-Inches%2C-Chrome/674843 Link to comment Share on other sites More sharing options...
Pete Lewis Posted June 24, 2020 Report Share Posted June 24, 2020 i just use a reversed 3/8drive socket with a bi hex that fits a ratchet drive all a bit back to front but works for me Pete Link to comment Share on other sites More sharing options...
yorkshire_spam Posted June 24, 2020 Report Share Posted June 24, 2020 I have a "vintage" King Dick 3/8 ratchet that has the "push through" drive on the end... take that out and add a short 3/8 extension (if required) and it's great for square section plugs. A bit like this: Image stolen from the interweb google image search. Link to comment Share on other sites More sharing options...
Mad4classics Posted June 24, 2020 Report Share Posted June 24, 2020 All mine have a 7/16 square head so I picked up a Martin Tools 265H 4 point wrench from ebay. Link to comment Share on other sites More sharing options...
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