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Sump plug thread


Gadgetman

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NPS National Pipe Seal?.

4 different threads?
BSPP
BSPT
NPT
NPTP NPS
It is clear which are parallel threads and require a seal ring & which are taper threads and do not require or could use a sealing ring.
A/F is not diameter same as Taper diameter is not marked size. Marked size is suitable pipe size to connect.

BSP means nothing. M20 plug. A/F or diameter?

Be nice to see a magnet on the filtered flow?

PS. I thought the oil pressure was NPT and the galley plugs on the 6 the same.

Edited by SpitFire6
NPTP Not!
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49 minutes ago, SpitFire6 said:

PS. I thought the oil pressure was NPT and the galley plugs on the 6 the same.

There are definitely a good few NPT threads in the oil-ways of the Triumph 6, but not all of them the same (maybe not even all NPT)

Then there's that aluminium beast of a plug above the filter, which is some huge taper thread, tightened up then battered flat to prevent you undoing it.

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5 minutes ago, NonMember said:

There are definitely a good few NPT threads in the oil-ways of the Triumph 6, but not all of them the same (maybe not even all NPT)

Then there's that aluminium beast of a plug above the filter, which is some huge taper thread, tightened up then battered flat to prevent you undoing it.

I've ordered 4 1/8NPT pressure transmitters. Screwed if they are not.

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56 minutes ago, NonMember said:

Then there's that aluminium beast of a plug above the filter, which is some huge taper thread, tightened up then battered flat to prevent you undoing it

That one is actually UNF. 3/4" IIRC  I have a chunk of cut-down bolt in mine.  Itself drilled and tapped to take a fitting to feed my external oil pipe to the front of the main gallery.  The gallery plugs are a nightmare on the six. No logic at all.

Nick

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On the previous page there was ref to 1/2in sump drive sockets I sometimes use the sq drive, but 15 years ago I brought these profile cut spanners made from S/S esp for sump plugs off UK ebay, very well made and have the two ends orientated at 90 degrees so you can always fit in a tight place. The spanner is 1/4in thick.797507297_Flat0.5insqStainlessSumpSpanner.JPG.c6f9a581ae5795c0aedefd3cb1e0d08e.JPG

I brought and a dozen for our clubs shop and they all sold. 

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12 minutes ago, Paul H said:

Should the copper flat washer on the Canleys magnetic sump plug be changed yearly ?

Paul 

New washer every time you change the oil - or just anneal the old one with a blow torch and reuse it

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1 hour ago, Pete Lewis said:

isnt it amazing  who would have thought     4 pages on a sump plug   ...brilliant 

Pete

Lets see if we can hit 5 pages !

On the todo list for my Vitesse is to add a drain plug to the diff . I have the tapered square end plug . What sized drill do I need plus tap spec. 

If there is a more suitable plug would go with that 

Paul 

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1 hour ago, Paul H said:

Lets see if we can hit 5 pages !

On the todo list for my Vitesse is to add a drain plug to the diff . I have the tapered square end plug . What sized drill do I need plus tap spec. 

If there is a more suitable plug would go with that 

Paul 

Yes, the one that is removed with an Allen key. Square ended are no good.

npt brass.PNG

Edited by SpitFire6
added pic
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On 24/06/2020 at 09:26, Colin Lindsay said:

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. 

OK, @Pete Lewisand @Colin LindsayI'm trying to get to a fifth page.

Unsurprising  I haven't got a 3/8 NPS bolt; so thinking about your comment I made up a GO NOGO gauge for the internal IDs' of NPT and NPS because curiosity got the better of me.

I've got an FD axle with no drain plug and measuring the casing threads in that it's definitely straight i.e. NPS.

Now, I've got a really odd early alloy gearbox with Spitfire ratios fitted (some PO might have had aspirations to racing?); measured the casing threads on that and it's definitely tapered i.e NPT. Even to the naked eye you can see it's tapered!

I didn't want to test the engine sump drain plug as I've only recently changed the oil; but I suspect it will turn out straight perhaps when I get a chance to measure it.

So I've got a mix of straight and taper casing threads but the same plug fits all of them!!!!

This then goes back to my comment about bean counters; did Triumph start using the straight thread a) With the cast iron casings? b) When the diff drain plug was dropped as an additional cost saving? ( I haven't got an early one to measure) c) Is the gearbox always different anyway????! (I haven't got a later one to measure.)

The other thing I found was that the one original plug I've got is 3/8" square whereas all the replacements I've bought because they'd been badly mangled are 7/16 square. do'oh!

I remember coming across a thread on another triumph site where an owner had fitted a straight plug in a taper alloy casing hole and stripped the thread by over-tightening it. The fit of straight plug in a taper casing is all wrong!

The bottom line is I think you need to know exactly what you've got before you depart from the taper plug Triumph specified.

But if you're after something different, a search for 3/8NPT plugs in general threw up Advanced Fluid Solutions they've got all sorts and they have an eBay outlet.

https://www.advancedfluidsolutions.co.uk/solid-hex-or-allen-key-male-blanking-plugs-481-c.asp

 

So rather than completely answering this I've thrown up more questions. Going for that fifth page!

David

 

image20200625_120213796.jpg

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5 hours ago, SpitFire6 said:

The brass plug will never corrode in cast iron or steel.
304SS will also never corrode

In the Galvanic Scale stainless steel is further away from iron than brass. This scale gives the liklihood of corrosion between materials. Providing the material is fit for purpose the closer the materials are the better to prevent corrosive interaction. 

Are we getting near page 5? I'm sure some chemist's or metallurgist would love to chip in! 

Iain 

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3 minutes ago, Iain T said:

In the Galvanic Scale stainless steel is further away from iron than brass. This scale gives the liklihood of corrosion between materials. Providing the material is fit for purpose the closer the materials are the better to prevent corrosive interaction. 

Are we getting near page 5? I'm sure some chemist's or metallurgist would love to chip in! 

Iain 

Correct. Brass is more noble than ferrous. The ferrous will corrode as its anodic.

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