I assume that asking a question about oil pressure represents a rite of passage for a new owner? '32 RP.

When I bought the car it had what looked like old, dirty oil in it. It ran at around 2 to 4 psi when hot.

I changed the oil for sae 30 and the oil pressure has dropped to around 1 to 3 or maybe 4 psi when hot. The gauge flickers around nicely but you get the general idea.

Having read as many of the posts on this topic as I could face I ask two questions:

Is this pressure range acceptable OK for an older engine?

Would there be any benefit from putting in something thicker, ie sae 30?

I think oil consumption may be quite high but since it both uses and loses oil it is difficult to tell, need to get to know it better.

Sounds fine to me. SAE 30 or 20W50 will do. What you don't want is a full scale reading when hot, which could indicate a blocked oil jet. You can get a zero reading at tick-over when hot. Don't worry about it. Check your oil jets are clear - remove the blanking nuts either side of the filler tube on the crankcase and poke them clear with a wire. My RP does about 150 miles to the pint, some through use some due to leaks.

Location: Gard, France 30960

Sounds perfect to me!

Location: Herefordshire, with an "E", not a "T".

Thanks all, I'll have a go at worrying about something else!

The reason for the low oil pressure, Michael is due to the design of the lubrication system in a standard engine. The crankshaft is not pressure fed but has wells in the crank webs which catch oil from the "spit & hope" system and centrifugal force created by the rotating crankshaft directs it to the big ends. The low pressure oil spray is sufficient to lubricate the bearings and everything else.

here's a picture of my dashboard taken when the car was running virtually flat out - oil pressure is about 2.5psi



(The more eagle-eyed on the forum may note that the speedo is from a Nippy)

Location: Gard, France 30960

Reckless,

They aren't cross head screws are they?

Tony

Location: Malvern, Melbourne, Victoria, Australia.

Tony,
We've been here before with Recker's roofing bolts!
Cheers,
Dave.

Location: Sheffield

I have the same speedometer on my RP...and what is more that is same reading I always have on my fuel gauge!

I have some experience of non pressure fed systems, had a Railton once whose Hudson engine was 'splash' fed, each big end having a scoop and a trough of oil into which it dived...but no oil pressure gauge to worry the uninitiated.

Michael

The Austin Seven is still pressure fed.

The pump provides oil under pressure which varies from 15-20 psi cold to 2-3 psi hot, which as you know sprays through jets into rotating pockets on the crankshaft.

The front and rear camshaft bearings are also pressure fed by the same system.

The original dashboard 'button' was apparently provided so the widely varying pressure didn't worry the driver - obviously by the 30's people understood the wide range was OK.

Tony.

Location: Malvern, Melbourne, Victoria, Australia.

Hi
How many hands did you need on the wheel at 50?
Colin

Colin - that reminds me of the old gag - "Fred darling, I do wish you'd use both hands instead of one". "I'd love to, Honey - but how am I going to steer the Chummy?". Back to the far corner. Cheers, Bill in Oz

Location: Euroa, Down Under

Driving the RP at 50 is what one would call "challenging"...

Location: Gard, France 30960

...and in combination with photography, or other pursuits... even more so?

Michael,
Returning to the thread. In view of the old, dirty oil found, I would have dropped the sump and cleaned both it and the filter. Putting new oil into such an engine is somewhat of a waste I fear.

Location: Melton Mowbray

I trust Colin and RR are not implying that stock Seven handling at full tilt on indifferent surfaces is in any way demanding. Such aspersions seem to be one of the sins I am regularly accused of.

Except when control was becoming very marginal I did most of my Seven driving using one hand. This allows a degree of spring which absorbs the steering reaction arising from shortcomings in the steering layout. A vice like two handed grip promotes wander. When the cars are rocked the steering wheel turns whereas it should not. If restricted, the wheels turn instead.The reason many recommend some play in the box.

And returning to the topic, stating the obvious, but some new to Sevens may have missed; with 2 brg Sevens the wear of bes and main bearings, factors which very much influence oil pressure on other cars, has no influence.

Raised pressure may mean a blocked jet... it also creeps up with clutch slip! The gauge should not flicker

For any particualr oil, rate of oil discolouration is related to consumption. Blackness alone is not serious, as evidence diesels, but if rings are broken and/or gaps very wide increased carbon debris accumulate in the sump. Whether or not this comes from the combustion chamber I dunno.(Based on post mortems of filter elements of various family cars over 45 years)

Location: Auckland, NZ

A further subtlety with lack of proper oil pressure was covered in the thread 'Chummy Oil Pressure' in April 2014 - and brilliantly diagnosed by Ruairidh from hundreds of miles away. This is the possibility that the oil pump vanes are placed in upside down - with the tiny chamfer at the bottom. Oil still circulated but the pressure did not go off-scale for long when cold, and was reluctant to leave zero when hot on revving. See relevant thread for further details...
Colin

Flickering of the gauge when going round left hand bends is a very bad thing.

It means you have forgotten to top up the oil yet again and have to return home only using right hand bends.

( Think it is that way round!)

Simon

Location: On a hill in Wiltshire

I had to think about that one too. Centrifugal forces versus gravity plus road camber.
I think your answer is correct.

Location: Bonnie Galloway

Another possibility for a low reading could be the relative angular positions of the needle and the bourdon tube in the pressure gauge if it has been messed about with.
Dave.8

Location: Sheffield