Morris Minor Owners Club

Can anyone help me with some advice on oil pressure?

my oil pressure gauge was/is reading zero! at first i thought it was the gauge at fault, but after looking into it further, i do seem to have no pressure.

checked the gauge pipe all the way back to the block, no problems with the pipe. With pipe off of the block, cranked the engine to see if any oil would spirt out, not much to report, just a little dribble of oil

removed the oil filter and pipe to the block, pipe not blocked and filter not too bad. cranked engine over, with ignition off, and thumb over oil way to feel the pressure from the pump, but nothing much to report

took thumb off and oil did pump out

how much pressure should there be from the pump when cranked over?

just wanted to check that I'm diagnosing the problem to be the pump correctly before i take the engine out

thanks in advance for any advise given

What does the engine sound like when its running?

With no oil pressure Id expect it to be sounding very ill indeed.

Ive never experienced no oil pressure before. Only three reasons I can think of is:
1. No oil in the sump;
2. Very worn oil pump and or engine;
3. or perhaps your oil pressure relief valve is stuck open and anything your pump produces in the way of pressure your simply loosing through the relief valve.

I wouldnt expect any oil to lifted into the oil pump if youve temporarily removed the oil filter mind.

regards

Steve

Is the oil pressure warning light working?
Do you have any oil pumping from the rocker shaft?

Check the relief valve as mentioned- with cold oil and no spark plugs in, the starter should be able to generate 60 psi after a few seconds (maybe 20/30 seconds) churning. If you can't get this - don't start the engine. The filter is after the pump - so removing the filter has no effect on the pump priming. You could remove the sump and check if the suction pipe has maybe come loose - or become completely blocked with crud......
An engine run with no oil pressure destroys itself in seconds - so unless you switched off 'immediately' - it's likely you need to pop the engine out anyway....

firstly, thank you all for your input

the engine sounds and runs fine with no oil light coming on on the dash. oil is also reaching the rockers! the sump is, if anything, slightly over full! (about 5 mm over the mark on the dip stick)

i have attempted to take out the pressure relief mechanism with no luck, it seems to be stuck! any suggestions for freeing it as it seem to be smooth on the inside and I'm unable to get ahold of it with anything. this means that I'm unable to confirm if its open or shut, but i suspect its wedged shut but do need to make sure that this is the case as it would explain everything

taking the plugs out is a good idea, as this will give me more crank speed, thanks for that. i will also drop the sump and check the suction pipe for clogging!

thanks again

The relief valve would need to be jammed open to have no oil pressure. A piece of wood dowel (handle of valve grind tool) pushed into the valve and wiggled about usually gets it free. Normally however it just slides out on the end of a finger! If the light goes out - and oil appears at the rockers - does sound like failed gauge. Can you beg/borrow/steal another gauge to try it ?

If you did not have a gauge you would not be worrying