Colin Posted June 12 Report Share Posted June 12 Hi Chaps, I quite fancy a magnetic sump plug for my 1200 saloon. Merlin Autosports have loads, but I'd need to know what the plug thread is. Does anyone have a spec., please?? Best, C Link to comment Share on other sites More sharing options...
Colin Lindsay Posted June 12 Report Share Posted June 12 Here's a five-page thread.... Link to comment Share on other sites More sharing options...
johny Posted June 12 Report Share Posted June 12 Yes that is quite a read and unfortunately I think things might be even more complicated as indicated by this article: NPTF - National Pipe Thread Fuel (Dryseal) Threads (machiningdoctor.com) Its says our 3/8 x 18 'Dryseal' plugs use an NPTF thread which is derived from NPT but the tolerances are tighter so that an interference fit of the thread root and crest is guaranteed. In plain NPT threads this isnt guaranteed so a seal may not be achieved which could explain why if weve been using only NPT items they so often leak. The main Triumph part stockists supply magnetic sump plugs but I would guess they are not NPTF and indeed some even come with a copper washer for sealing but of course this depends on the surface surrounding the plug hole which was never originally designed for it.... Link to comment Share on other sites More sharing options...
Nigel Clark Posted June 12 Report Share Posted June 12 It's well worth having a magnetic sump plug, especially when running in a new engine. When running in, there is inevitably some ferrous swarf as the new piston rings bed in. Much better to have it caught by the magnetic plug then circulating until the filter captures it. For an older, well run in engine, the magnetic plug may be less important, though still worthwhile to catch the smaller amounts of ferrous rubbish that may be circulating in the oil. It's also worth having a magnetic drain plug in the gearbox. If the synchromesh is a little weak, or a gear change crunches, the dogs on the gears and collars will produce swarf. Nigel Link to comment Share on other sites More sharing options...
johny Posted June 12 Report Share Posted June 12 Which type have you found seal reliably on our cars Nigel? Link to comment Share on other sites More sharing options...
Colin Posted June 13 Author Report Share Posted June 13 Hi Colin. Apologies for not having spotted that thread. Gearbox plug would be good, too. Who hasn't accidentally crunched a gear or two? However, I'm not sure I'm clear about which thread is correct (and . . . is the g'box the same?)! Our original plugs are interference fit, aren't they? So should I be looking at the 3/8 x 18 NPTF, as mentioned? Nobody seemed terribly definitive about a replacement . . . (or am I just being dim again?!?) Thanks and Best, C. Link to comment Share on other sites More sharing options...
johny Posted June 13 Report Share Posted June 13 As I say, to be sure, all the Triumph suppliers sell part number 155660 as below for our cars. It uses a copper washer to seal which presumably works... Link to comment Share on other sites More sharing options...
Paul H Posted June 13 Report Share Posted June 13 10 minutes ago, johny said: As I say, to be sure, all the Triumph suppliers sell part number 155660 as below for our cars. It uses a copper washer to seal which presumably works... I have (had) them on my Vitesse on gearbox and sump but they always leaked. Purchased from Canleys Paul Link to comment Share on other sites More sharing options...
johny Posted June 13 Report Share Posted June 13 Yes its asking a lot to seal with a washer when the casings werent designed for it☹️ Link to comment Share on other sites More sharing options...
Gary Flinn Posted June 13 Report Share Posted June 13 Surely a tight fitting rubber 'O' Ring in conjunction with the copper washer would stop any oil leaks on the Magnetic plug if it's not a Tapered thread? Gary Link to comment Share on other sites More sharing options...
Colin Posted June 13 Author Report Share Posted June 13 1 hour ago, Paul H said: I have (had) them on my Vitesse on gearbox and sump but they always leaked. Purchased from Canleys Paul Which is not much of a help, it leaking when cold & not expanded under heated conditions! Choice:- trap swarf but lose oil when cold standing . . . and Gary, surely a rubber 'O' ring would burn off or harden, crack, then break away after not too long (back to oil loss when cold . . .🙂)?? Link to comment Share on other sites More sharing options...
Gary Flinn Posted June 13 Report Share Posted June 13 18 minutes ago, Colin said: Which is not much of a help, it leaking when cold & not expanded under heated conditions! Choice:- trap swarf but lose oil when cold standing . . . and Gary, surely a rubber 'O' ring would burn off or harden, crack, then break away after not too long (back to oil loss when cold . . .🙂)?? Colin If you get the right type of 'O' ring (Nitrile maybe?) it would be ok. Think about it, there are 'O' Rings sealing the Oil Filters on our cars and they are fine, I don't think it would get that hot anyway. Gary Link to comment Share on other sites More sharing options...
Pete Lewis Posted June 13 Report Share Posted June 13 the base design of all our plugs is to use a tapered threaded plug none of the faces are machined to accept a washer as a sealer . its only lasted 50 years . its a bit late to get paranoid and guys fancy reinventing a simple design that works . what you may collect on a magnet is pretty insignificant if you wish stick a old magnet to the side of the filter !! this mag plug is just a worry update that will leak Pete 1 Link to comment Share on other sites More sharing options...
JohnD Posted June 13 Report Share Posted June 13 If you have a magnetic sump plug, you will fund something like this on it. A horrifying christmas tree of spikey bits! Gosh that magnet is doing its stuff! But wash that plug in degreaser, and pinch off the bits between your fingers. You will find that there aren't any bits - the spikes are an artefact of the magnetic field, and what you have between finger and thumb is the finest powder, like talc. The finest particle that can be finger-felt is about 50 microns - that small! - and this is finer than that, but still will be caught by the oil filter. JOhn 1 1 Link to comment Share on other sites More sharing options...
DanMi Posted June 13 Report Share Posted June 13 I use this one tapered just as original and a nice big hex head https://www.ebay.co.uk/itm/285743345275?itmmeta=01J08K2JG26YV6WXHHNDAC791M&hash=item4287a16e7b:g:k9IAAOSwq21ixWmi&itmprp=enc%3AAQAJAAAA4AgDW79IjplPg9X4JvyU0ruHwn2kBbuEeCPWDFTPz9MHW17mwxLwuz9X3Q3s%2BZ5aJydYHJKKM7CcOQMyaV9E42n9EZVZM7rNAzZ4rXUr197Q0fEtPL3PWc41TZ%2FGApNcPNsfmi2ssITBeG9A%2F9kgnBR3G4Nv7yhGFw737323fI4glA7PhfSJRESzk9ODOOq93OcAKN1ZSOchlPJV50iLUXJ7nmm3FkYbYtfZUth0jXhgGgEAUwEuQyVDTouiugIYn8pc4TNDsvEaSc7AlAPqnzv6sO6w5lMbvUR%2Bk12WVW2Q|tkp%3ABk9SR5KoipOCZA and from a well known Triumph trader Link to comment Share on other sites More sharing options...
Colin Posted June 13 Author Report Share Posted June 13 All good comments - Gary, I did think after I said it that nitrile might work. TBH, the car leaks a bit anyway. At 143k miles, I expect it. I leak at 66 years old! 🤣 Link to comment Share on other sites More sharing options...
Eric Smith Posted June 13 Report Share Posted June 13 Back in the 1960’s my Father worked for GKN making nuts, bolts and various fasteners for Ford and other companies in the motor industry - as part of a contract they were making sump plugs. After making the sump plug they drilling a hole in the end of the plug and dropped in a circular section bar magnet which was about 10mm long. The moral of this little story is, go to a model shop, buy a magnet, drill a hole, dob of superglue, drop the magnet in - job done! Eric Link to comment Share on other sites More sharing options...
Colin Posted June 13 Author Report Share Posted June 13 That's a neat solutiion, Eric. Not too far off Pete's remarks! DanMi - I was just looking at those. Eric's inexpensive solution is tempting! Did you find you needed a washer of some description? Best, C. Link to comment Share on other sites More sharing options...
Eric Smith Posted June 13 Report Share Posted June 13 Glad to be of help, neat easy solutions are always the best. Eric Link to comment Share on other sites More sharing options...
dannyb Posted June 13 Report Share Posted June 13 39 minutes ago, Eric Smith said: drill a hole, dob of superglue, drop the magnet in - job done! Eric That's exactly what I did having a number of magnets knocking around. Danny Link to comment Share on other sites More sharing options...
Peter Truman Posted June 13 Report Share Posted June 13 Similar but a tight fit no glue Previously I had brought a aftermarket mag sump plug with tapered thread it leaked like a sieve so I reverted to an old original supply plug drilled the hole and transferred the magnet All hood now Link to comment Share on other sites More sharing options...
Colin Posted June 13 Author Report Share Posted June 13 Way to go, Chaps. I like these low-cost, practical solutions! Thanks, Best, C. Link to comment Share on other sites More sharing options...
Colin Lindsay Posted June 13 Report Share Posted June 13 2 hours ago, Eric Smith said: Back in the 1960’s my Father worked for GKN making nuts, bolts and various fasteners for Ford and other companies in the motor industry - as part of a contract they were making sump plugs. After making the sump plug they drilling a hole in the end of the plug and dropped in a circular section bar magnet which was about 10mm long. The moral of this little story is, go to a model shop, buy a magnet, drill a hole, dob of superglue, drop the magnet in - job done! Eric The other alternatives are to either stick a large speaker magnet to the outside of the sump - make sure you get one that will grip and not fall off on the first bump - or else tape one to the outside of the oil filter. The amount of debris they'll capture is frightening. Someone used to make a magnetic collar that was fitted round the filter, but easily copied. Link to comment Share on other sites More sharing options...
johny Posted June 13 Report Share Posted June 13 2 hours ago, DanMi said: I use this one tapered just as original and a nice big hex head https://www.ebay.co.uk/itm/285743345275?itmmeta=01J08K2JG26YV6WXHHNDAC791M&hash=item4287a16e7b:g:k9IAAOSwq21ixWmi&itmprp=enc%3AAQAJAAAA4AgDW79IjplPg9X4JvyU0ruHwn2kBbuEeCPWDFTPz9MHW17mwxLwuz9X3Q3s%2BZ5aJydYHJKKM7CcOQMyaV9E42n9EZVZM7rNAzZ4rXUr197Q0fEtPL3PWc41TZ%2FGApNcPNsfmi2ssITBeG9A%2F9kgnBR3G4Nv7yhGFw737323fI4glA7PhfSJRESzk9ODOOq93OcAKN1ZSOchlPJV50iLUXJ7nmm3FkYbYtfZUth0jXhgGgEAUwEuQyVDTouiugIYn8pc4TNDsvEaSc7AlAPqnzv6sO6w5lMbvUR%2Bk12WVW2Q|tkp%3ABk9SR5KoipOCZA Were these oil tight? As the article indicates its not just the taper thread you want but one with tolerances that interfere at the tips. Otherwise you can pull it up as tight as you like but theres still a spiral channel all the way around the thread to allow a steady leak of oil.... Link to comment Share on other sites More sharing options...
JohnD Posted June 13 Report Share Posted June 13 (edited) The swarf on a mgne5iv sump.plug can.look horrifying! The spikey bits of metal look as if they could do real.damage! This is my gear box plug, today. But their appearance is an artefact of the magnetic field. Wash the plug in degrease, and pull off the swarf with your fingers. You will find that it is in fact the finest of powders, like talc. The particles are microscopic. Your fingers are VERY sensitive! Any particle you can feel is probably only 50 MICRONS across! John Edited June 13 by JohnD Link to comment Share on other sites More sharing options...
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