oil gallery plugs.

[dazzer]

This has been visited before (sorry cant locate the thread) but thought I'd revisit as I've just replaced on the latest re incarnation of my rally engine.

I'm referring to the small 1/8 NPT hex head alloy bungs along the oil gallery. However you approach removing these, sometimes they come out, sometimes they don't without a struggle. Anyway once you've got them out finding replacements is a difficult task. You can order them blind off ebay or go to your local engineering supplies who probably wont have 1/8 NPT end caps off the shelf.

However they will have 1/8 BSP and they fit perfectly with a nice resistance and they come in different deigns either with the Allen key head or my preferred with a proper socket head. Not aluminium but stainless or plated steel.

Getting them out: Heat seems to be most effective and also try clockwise first then anti. If you round off the hex head (easy as very soft) drill out the centre and hammer in an old flat blade screwdriver and twist with a HD pair of grips (works for me)

Hope this helps.

[Nick Jones]

Thanks Dazzer - good info.  I always thought they were 1/8" BSP - it's the end ones which are weird and different end to end.

If they round out I usually beat a torx bit into them.  That technique also works on the aluminium plugs (above oil filter housing and main gallery front end) but you drill a suitable hole first.

Nick

[dazzer]

Hi Nick

Yes, maybe they are 1/8 BSP and have been all along, although NPT seems to have been quoted most often on older threads.

Cheers

Darren

[RobPearce]

When I did Tessa's engine I found that the small ones were 1/8 BSP but the bigger ones at the ends of the main gallery are NPT. Go figure.

[Nick Jones]

I think the gallery ends are different with one being NPT and the other BSP.  In practice BSP and NPT are very nearly the same at that particular size but it's a very odd thing to do - and the big gallery plug above the oil filter (normally aluminium) is a parallel 3/4" UNF thread.

Nick

[nang]

Only one thread different, BSP 28 tpi, NPT 27tpi. Diameters about the same.
Someone will tell me why B.L. used NPT. 😀
Tony.

[piman]

Hello Tony,

someone on the Triumph 2000 register answered that some time ago by saying that the NPT plugs sealed better than BSP.

Alec

[Hogie]

Hi Folks,
                 NPT is a taper thread and would naturally seal by simply tightening.

BSP could be tapered if stated (BSPT)

Does sound odd though.  There are a number of oddities on the ST cars.  Eg. Overdrive inhibit switch thread size. People say it is 16x2mm   but it has 13tpi.


Roger