Bristol - Smiths oil pressure gauge

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Mon 10 May 2021 17:36
Bristol - Smiths oil pressure gauge - Kingjohn

I disturbed my oil pressure gauge (Smiths OP217) trying to fit a new illumination bulb.

Now, when turned off, the needle only drops to about 9 psi. Is there a way to adjust the instrument to get it to drop to zero without removing it (don't want to disconnect the pressure pipe)?

Currently when I turn off the needle drops to 20 psi and then slowly falls to 9.

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Mon 10 May 2021 18:05
Bristol - Smiths oil pressure gauge - elekie&a/c doctor
This will be a bourdon / capillary mechanical gauge. Don’t think there is any external adjustment. Have you kinked the pipe ? I would release the pressure pipe from the gauge to see if it resets to zero. Be careful when removing the pipe , there is usually a small sealing washer that falls off .
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Tue 11 May 2021 12:54
Bristol - Smiths oil pressure gauge - Kingjohn

Will letting air into the system effect the reading when it is reconnected?

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Tue 11 May 2021 14:01
Bristol - Smiths oil pressure gauge - bathtub tom

I remember fitting these in a previous life, decades ago in the last century. Used to bleed them with the engine running and slackening the nut holding the pipe. Could get messy! IIRC the needle would jump around if there's air in the system.

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Wed 19 May 2021 16:34
Bristol - Smiths oil pressure gauge - Kingjohn

That is what I was arfaid of!

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Wed 19 May 2021 20:11
Bristol - Smiths oil pressure gauge - Big John

I'd second checking for a kinked pipe - be careful though old small oil pipes might be brittle now and easily split. I once damaged an oil gauge pipe on a Ford Capri which took a while to spot and my goodness the oil that ran down to the footwell made things rather dangerous and the carpet was never the same again. Thinking about it I think that was replacing a dash instrument light bulb as well. [EDIT - from what I can remember that is, just worked out it was 36 years ago!]

Edited by Big John on 19/05/2021 at 20:37

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