2 QUESTIONS.

[John Mason]

As to the coil in the feed pipe to the oil ptrssure gauge. It’s only there to give a bit of flex to the pipe to stop possible fracture of it as it vibrates. It does not alter the pressure at all.

John Mason.

[Mike Costigan]

I would expect a standard 3-bearing engine to run up to about 8psi when hot (maybe 2-3psi at tick-over), so I would not be unduly concerned about a 10psi reading. If that jumps to 15-20psi (when hot - 20+psi can be expected when starting from cold) then I would be investigating a blocked jet pretty smartly, but none of these pressures will be sufficient to activate the PRV; my guess is that the PRV is probably set to something like 30-40psi.

[Chris KC]

The only benchmark I'm able to offer is that the (adjustable) PRV on the Reliant Regal was set to approx 40 psi.

Last time I looked at one I seem to recall the spring was identical.

[Bob Culver]

Charles Lindbergh had seen many air crashes. For the special plane comstructed for the Atlantic he insisted that there were no unbroken lengths of pipe beyong 2 or 3 feet or somesuch. 
Cars with extensive hidden copper pipe feeds inside, as larger Austins,  are a worry.
 I guess as much as anything the valve protects the gauge and the pump drive. I have seen defective and wrong valves on other cars go beyond 100psi.

[Dave Wortley]

I have tried at least 3 A7 oil gauges on one car and they all gave different readings (Can't remember what they were, I was checking that they all worked)¾

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3/4!!!!?

[Howard Wright]

Hi

On my bog standard 2 bearing RK the gauge goes off the scale on start up but when hot (several miles on) registers zero on tickover and about 3 to 5 psi at 2000+ revs.

On my special with a bored out pump it registers about 25 psi on start up, 5 psi on tickover when hot and about 10 psi at 2500 revs.  I fitted a 30 psi gauge and have a T’d connection in the pipe to a switch that registers when the pressure exceeds 14psi. This lights a panel light as an extra warning of a blocked jet. 

Coiling the oil pipe just provides some flexibility between the engine and gauge. On the special I’ve switched to a plastic pipe.

I wish I could get to the release valve as I have a small leak coming from it  .

Cheers

Howard

[Dennis Nicholas]

And don't forget the coil should be horizontal and not vertical where any muck would collect in the lowest point.

[Malcolm Parker]

One of the problems with Austin 7's, especially at this time of year, is that they never get up to optimum temperature and the oil isn't warm enough to give a proper reading.   I did a run of about 60 miles in the Ulster this morning (standard jet feed and oil pump, 20/40 oil) and the oil pressure reading was a bit higher than normal.  On stopping after 25 miles the radiator header tank was warm but by no means hot.  I don't worry too much about the oil pressure.  It's a bit like your blood pressure, if you worry about it too much you will bust a blood vessel!

[Chris KC]

One of the problems with Austin 7's, especially at this time of year, is that they never get up to optimum temperature and the oil isn't warm enough to give a proper reading.   I did a run of about 60 miles in the Ulster this morning (standard jet feed and oil pump, 20/40 oil) and the oil pressure reading was a bit higher than normal.  On stopping after 25 miles the radiator header tank was warm but by no means hot.  I don't worry too much about the oil pressure.  It's a bit like your blood pressure, if you worry about it too much you will bust a blood vessel!

One thing never to forget is that water temperature and oil temperature are two entirely different things. It's quite possible to have the radiator boiling away merrily and the oil in the sump still cold.

[Malcolm Parker]

I'm assuming that the radiator is working as it should, Chris. In over 45 years of Austin 7 ownership, driving in a hilly part of the world, I've only ever had the radiator boiling away merrily once, that was when there was a leak at the joint between the core and header tank and the thermosyphon effect was lost.