9 replies to this topic

[Brett]

my query i read many places that the oil pressure u run doesnt need to be high just constant? am i correct....my problem atm the oil pressure is like constantly low... idle about well off the oil pressure guage (low) but not triping the oil pressure light on so i guess above ~7psi the pressure pickes up ofter this to about 35-40 psi at driving my first check will be the pressure release valve because the presure sat at about 50 psi idle and then went to about 75 at driving when pulled up and the pressure was gone, if the valve was stuck open that would cause this problem right?

would there be any damage to the engine if i cant get the pressure up and i drove it 6 miles to my garage? where i can get it stripped.
considering the pressure is 30+psi when driving

cheers,

[minidaves]

no 30-40 psi oil pressure is still enough to protect the engines crank and a lot of engines did not run that high anyway, I drove me mini back from germany a few yrs back with around 12psi and the crank was fine, just me oil pump was knackered.

Just dont work it hard and get it seen too

dave

[dklawson]

Oil pressure may be specified in technical manuals somewhere but I've seen people post acceptable pressure levels that span quite a range. I got frustrated a while back and posted a query on another board I visit.

In my query I asked what most seasoned A-series engine owners considered "normal" and "acceptable" oil pressures for a HOT (warmed up, after a high-speed run) A-series engine, idling at 900 RPM.
Most said on a rebuilt engine in good condition an idle oil pressure close to 35 was common and acceptable while on a higher mileage engine anything above 25 psi was good. They went on to say that anything below 25 psi on a high-mileage 1275 would probably indicate sufficient wear to consider maintenance. A few reported higher oil pressures on a fresh rebuild but they were the exceptions.

Again, the figures above were based on my specific question about a hot engine idling around 900 RPM.

[Brett]

yeah cheers guys, theres somthing up with my oil pump or gasket getting nice 50 psi at fire up (after repriming the pump ) and drops of from there realy, drives (over 2000rpm) between 35 and 45 psi but down to almost nothing at idle the pump is new from avonbar but the gasket is cheapo so fingers crossed its that thats *******ed and allowing air and oil to pass

[Big_Adam]

My oil pressure drops too after a wee drive. From 60lb start drops to right on 40lb on idle once hot. Just the oil thinning out with heating up.

[jobi-wan]

how much does it cost to get the oil pump replaced does any one know?

ive got a 1970-80 mini clubman 1098 cc my oil light stays on dont know what my pressures like.

my dad put oil in yesterday but its thinner than normal stuff so could that cause the light to come on???? help please

[dklawson]

"ive got a 1970-80 mini clubman "

So... does that mean your car is made up of bits and pieces of cars between 1970 and 1980?

On the early engines, the most common oil was 20W50. The thinner your oil when cold, generally the thinner it will be when hot. Consider changing to 20W50 if you're not using it now.

Before leaving this subject, has your Clubman just developed this oil light problem or was it there before the oil change? If it was there before, you probably are due for a pump replacement at a minimum. On high mileage cars dropping oil pressure can also be associated with worn bearings. Recent threads have discussed oil pump selection so use the search feature to hunt them down. As for cost... the cost of the pump is negligible compared to the labor cost because you have to pull the engine to replace the pump.

[jobi-wan]

oh i meant to say 1978 -80 not really sure which year it is.

i havent done the oil change yet, my dad topped up the oil to see if the light would go away but it didnt so ill find out tonight, i dont want to have to pull out the engine

[Guess-Works.com]

Think of the oil in the engine as it's life blood..

If it were you, and you had low or high blood pressure you'd be off to the doctor immediately...

Same with an engine..

The std oil pressure switch is designed to come on at somewhere around 10psi, which in my mind is already too low and your already causing damage to the engine. If your oil pressure guage is not registering and your light is not comming on then I would suspect the switch (or bulb) is fubar. Simple way to check is to earth the connecting wire on the sender, if the warning light illuminates then the bulbs ok so suspect the switch, and vice versa if it does not.

My preference is to have the oil pressure at around 25psi @ idle when hot.

When running, I set my oil pressure at 50-60psi when hot using an adjustable pressure relief valve.

I've had both instances of a pressure relief value sticking open and shut. The symptom for the former is, a rapid drop in oil pressure when slowing down to idle, running for any length of time like that, and it's good by mains and bigends. The latter is fairly ammusing, as you hear a loud pop as the oil filter seal gives way, and 3 litres of oil is shot out the into the engine bay and onto the floor...

Nowadays I use a ball bearing instead of the 'thimble', a modified spring and an adjustable cap on modified engines.... never had a problem since using that ( probably 15-20 years ago )

[jobi-wan]

Think of the oil in the engine as it's life blood..

If it were you, and you had low or high blood pressure you'd be off to the doctor immediately...

Same with an engine..

The std oil pressure switch is designed to come on at somewhere around 10psi, which in my mind is already too low and your already causing damage to the engine. If your oil pressure guage is not registering and your light is not comming on then I would suspect the switch (or bulb) is fubar. Simple way to check is to earth the connecting wire on the sender, if the warning light illuminates then the bulbs ok so suspect the switch, and vice versa if it does not.

right ive done an oil change new oil and new filter i oil light only comes on when im slowing down or cornering hard so it could be the pump. im going to change the switch and see what that does but other than that i dont know