Block to pressure gauge tube

[RichardHawkins]

I bought a replacement tube from Sue Miller. I don’t know which end fits the block and which end fits the gauge, neither does Sue.

I think I can work this out by the shape of the end fitting, but I am now worried about the possible confusion about threads. The Smiths gauge is 1/8” BSP (28 tpi) and the block will be 1/8” NPT (27 tpi). At the moment I cannot find the fitting that screws into the block that should enable me to measure the thread, I have a couple more boxes to sort through. I have sent an e-mail to Goodridge quoting their part number for this tube hoping they know which end is which.

Has anyone bought one of these tubes from Sue and sorted out which end is which and that the threads are BSP at the gauge and presumably NPT at the engine?

Richard Hawkins

[mbell]

I haven't bought this specific pipe but I have replaced it. The block end would be a 1/8 NPT male connection and my memory (possibly incorrect) gauge would be female 1/8 BSP. So should only fit one way.

The setup I got from Dave bean, used a AN3 braid hose with two convertors, one 1/8" NTP to AN3 and one AN3 to 1/8" BSP. The hose can be fitted either way but the convertors are end specific (NTP to block and BSP to gauge) and only fit one way.

[RichardHawkins]

Thanks for the reply, the hose that Sue sells has two female ends, making thread measurement tricky.

Richard Hawkins

[mbell]

Are you sure that there are no connectors that also came with it? The block has a female hole so you will need at least one convertor.

Mine came with AN3 hose with two female ends and two convertors. The clutch line that I got from Sue was similar if I remember correctly, AN3 line with convertors male/male convertors.

AN3 hose connections are 3/8-24 thread, which is same as used by the brake connectors and bleed nipples (except late +2 metric calipers). So should be able to use male brake connector or 3/8-24 bolt to confirm if hose thread is AN3.

[reds4se]

I replaced my line several years ago, i would be surprised if both ends were not similar with the block adapter being 1/8 npt / 1/8 bspp male/ male.These are readily available if you cannot find yours.Make sure you put the very small fibre washer on the gauge end connection.

[RichardHawkins]

Thanks again for the advice,

No fittings came with the tube from Sue. I do remember removing a fitting from the block, but have not found it yet, will purchase a replacement if necessary.

The small fibre washer at the gauge end. Thanks a lot as I do not have one, neither do I remember removing one, but I was concerned about how this end seals.

Richard Hawkins

[reds4se]

Check out the Speedograph Richfield webpage ( no association) as i think i got mine made up by them and they show the end nipple or olive detail and have the adapters if needed.

[oldelanman]

The small fibre washer at the gauge end. Thanks a lot as I do not have one, neither do I remember removing one, but I was concerned about how this end seals.

In case you want to make a sealing washer this was what was supplied by Speedy Cables with my refurbished gauge .....

[RichardHawkins]

Thanks both,

I had my gauges overhauled by speedy cables, I think I should look in the box more carefully among the polystyrene shapes used for packaging.

Richard Hawkins

[RichardHawkins]

I got a reply from Goodridge today telling me the fitting on each end is 1/8” BSP.

Thanks everyone for your help,

Richard Hawkins

[Andy8421]

While I am not suggesting it for road use, I came across one of these as I was looking to replace my oil pressure pipe:

https://www.competitionsupplies.com/mechanical-pressure-isolator

The argument being that piping hot, flammable liquid at high pressure to an area above your legs in the cabin is asking for trouble in a crash. Obviously not a problem for those of use with electrically operated gauges, but perhaps something to think about.

[RichardHawkins]

Andy,

Interesting object. Hot oil inside the car is a concern, but I probably won’t bother.

Richard Hawkins

[The Veg]

Interesting too that Lotus de-evolved on that over time: my Plus 2 has an electric gauge for oil pressure, but the 1986 Esprit I used to own had a little plastic tube that delivered oil to its gauge.

[mbell]

The late +2S130 also reverted back to the hose. Guess it was cheaper or easily available or something....