26 replies to this topic

[pierce]

I've changed the gearbox and head gasket on my mini but after it been running for a bit the oil pressure light comes on

[pierce]

come on someone must know whats up with it i need to fix it i want to go for a drive cause haven't had the car all week

[1976 clubamn]

are you sure that the head gasket was correct? if not i may have blocked some oil channels. or faulty oil press sensor

[Turbo Phil]

Did you remember to replace the rubber "O" ring between block and gearbox ?

Phil. :grin:

[pierce]

right gasket replaced o ring I have done about 10 miles with the light on no problems I replaced the sensor but I think its an electrical prob cause if i switch the ignition off when the light comes on then start the engine on it goes out again but then comes back on after a bit

[1976 clubamn]

in that case check all you earthing points

[pierce]

do you think its an electrical problem

[1976 clubamn]

could be, just try ruling all posabilitys out

[Woody]

It sounds like your oil pump is worn , when cold your oil is at its thickest and the oil pump works well , when hoter the oil is thiner and can pass through the wear in the pump causing low pressure .

[billtheminiman]

first of all, as uv mentioned the oil light comes on, after a while, it wodnt be a bad idea, to get one or if you alreday have one, an oil pressure gage.
And fit it, where the oil pressure light switch screws into the engine.

As, the indication of the oil light coming on is an indication that the oil pressure is low. A good figure on avg would be around 60lsb.
The problem either is, after running for a while, it developes a low oil pressure reading which would be indicated on the pressure gage, being below avg 20lbs instead of the 60 avg. If this is showing the average it is more than likely a faulty oil pressure switch.

If you do these tests you'll find out either youve got a major low oil pressure problem, or just a faulty oil light switch.

Then again, In theory if the engine after a while is still running and firing ok, smoothish i wouldnt expect it would be the head gasket problem., but if it isnt,and running lumpy, it could well be the head gasket, and might have a blown through the oil way between the head and the block in the gasket, wen you fitted the head gasket.

i know this all sounds abit difficult for me to explain but i hope you have got the gist of what im on about...

Do these tests and let us know.

But if you cant explain... il try and simply it for you.

billtheminiman

[1976 clubamn]

would do to check that out, it is fairly easy to do. you need some feeler guages to check the clearance on the lobes inside.

[billtheminiman]

Hi, what do you mean by lobes inside?




PS... also i have just had another thought, to the left and down abit from the oil pressure switch is a large hexagon nut ( located just left of the distributor), on the front of the engine. Facing you.
And inside is a spring and oil pressure relief valve.
Check the tension of the spring by measuing its free length. If it is shorter than the lengh of -72.63mm, it should be renewed. Check the condition of the cup, checking carfully for ridges which would prevent the cup seating effectivly.
Renew the cup if the condition is suspect. As this valve also governs oil pressures.


Therefore the problem could ly in the seating of the oil pressure relief valve, which may not be right.

Have you renewed your oil lately, as old US oil, would give you an low oil reading, incorrect oil for engine would vary the oil pressure. As i dont know what the year of your engine is. You may need 20 50 grade or if its a later mini 10 40 grade.

See how you go.

[1976 clubamn]

my pump has a star shaped eccentric gear inside that turns the points of the star are the lobes

[bluebottle]

i think the first thing i'd do is connect up an oil pressure gauge, take out the spark plugs, and crank it over, and see what oil pressure you have.
if you run the engine normally, and say, your big ends are worn, or your oil pump is shot, it won't take long to totaly kipper your engine.

[pierce]

Where is the oil pump on a mini and how hard is it to get to it