1098 oil pressure light pressure.

[Thomas.hewitt05]

Is there specific pressures that the oil light comes on and off at?

[Bill_qaz]

Depending on switch but normally 3 to 7 psi , I am sure someone will know the factory standard.

[philthehill]

Specified in BMC workshop manual Part No: AKD530L, Part AA, section AA.4 Oil Pressure - the low oil pressure warning light will glow (light up) when the oil pressure falls below 8lb/sq in.

[Bill_qaz]

So my upper guess was close Phil , when I was a mechanic we used to call them "too late lights"

[svenedin]

It is possible to find switches that operate at a higher pressure to give more warning and there are even switches that are variable.

Stephen

[geoberni]

So my upper guess was close Phil , when I was a mechanic we used to call them "too late lights"

I think it's fairly common that the Pressure Switch for the light is going to be a fair bit lower that the pressure at Idle speed.
You don't want it flickering like the Ign Light does when the engine is ticking over, people would be rushing to the garage all the time.....

Idle speed oil pressure is, according to the same part of the WS manual that Phill quoted, Approx 20psi.

[Bill_qaz]

But if it comes on driving its probably too late, much prefer a gauge, that's why
I have oil and temp guages next to each other, you get used to normal needle positions and notice if out of the norm, even when not reading the actual numbers.

20220310_131723.jpg (1.63 MiB) Viewed 4501 times

[philthehill]

It is always better to get an early indication of low oil pressure.
I have a 20lb/sq in oil pressure switch fitted to my Minor:- ttps://www.minispares.com/product/Classic/Engi ... %20searchh
a oil pressure gauge and a oil temp gauge.
This is the adjustable oil pressure gauge:-
https://www.minispares.com/product/Clas ... |Back%20to

[les]

Well of course I see the advantage of gauges but despite that I like the simplicity of just a couple of lamps, it’s a Morris Minor after all. For me it’s relaxed motoring, not worrying if I’m running a couple of pounds under pressure. The vehicle I recently sold had me playing that game, although it was more relevant in that.

[Bill_qaz]

An audible alarm wired to the higher pressure is also an option
As you say Phil an early warning of dropping pressure is preferable. Oil temp is particularly advantageous In a competition engine such as yours.
Did once have a rod exit the side of the block on the dyno before the oil pressure dropped, so guauge not infallible
Scary in the days when you shared the dyno room with the engine.

[Nickol]

A propos oil pressure readings. With the engine hot on my standard 1098 Traveller '69 vintage and travelling at say 80km/hr the oil gauge reads just under 50psi whereas the manual quotes 60psi for "normal running". I only get this reading when the motor is cold. Idling , it is difficult to tell as the gauge only shows 0, 50 and 100 psi but the warning light does not switch itself on and hte gauge certainly is not at zero.

My question is, should I be concerned? The car does not appear to be burning oil, runs perfectly ok and after a series of recent 500km trips, only needs an eggcup full of oil to top it up afterwards.

[liammonty]

A propos oil pressure readings. With the engine hot on my standard 1098 Traveller '69 vintage and travelling at say 80km/hr the oil gauge reads just under 50psi whereas the manual quotes 60psi for "normal running". I only get this reading when the motor is cold. Idling , it is difficult to tell as the gauge only shows 0, 50 and 100 psi but the warning light does not switch itself on and hte gauge certainly is not at zero.

My question is, should I be concerned? The car does not appear to be burning oil, runs perfectly ok and after a series of recent 500km trips, only needs an eggcup full of oil to top it up afterwards.

If it 'runs perfectly' then I wouldn't worry. The pressure at that speed (around 3000 rpm) is a little low, but not low enough to worry about. Has it dropped in comparison to what it used to be? That would be more of a cause concern.

As Les says, one issue with having gauges is they do sometimes cause unnecessary concern. I removed the aftermarket oil pressure gauge I fitted to my Type 2 VW as I spent too much time worrying about watching it when the engine always ran perfectly! I was more relaxed without it. That said, both of my Minors have got them (though the one in the Series MM is standard!).

[Nickol]

Thanks for that. Having read through some of the topics, I did come to this conclusion not to be too worried about it but at the same time, " proceed with caution". When you think we have just done 2550km in 2½ weeks in it, there cannot be much wrong.
I did have a similar problem with my other english classic, a Triumph Herald 13/60 and having had the crank reground, a new oil pump fitted, the oil pressure gave readings as per a new engine. I am therefore thinking of doing the same to the Morris during its winter hibernation and using the opportunity to smarten up the engine bay like so many of the great examples exhibited here in the forum..

[Sleeper]

I think it was Mr Chapman who said," oil flow is more important than oil pressure ", the Lotus elans having a 0 to 60 gauge....

John ;-)

[philthehill]

Overlooked points of generating oil pressure is that it it causes heat and saps power from the engine.
Oil also takes heat away from the friction points within the engine and passes that heat to the sump whereby in the airflow under and around the sump it is cooled.
50lb / in sq oil pressure is more than adequate for most peoples needs.

[MM1949]

AI, Thanks for replying to this old post.