Morris Minor Owners Club

Hi All,
Took the car out for its first long run today (Had to pick the hottest day so far!)
Noticed that when the engine was up to temperature the oil pressure when driving at 35-40MPH was between 20 and 25psi.
Is this fairly typical or should the reading be much higher?
Thanks

If you have the 803 yes (but didn't you say you had a 948?) in which case that's pretty low. What grade oil are you using and what is it hot idle?

Yes I have the 948cc engine, not sure what oil is in the engine at present but it is clean and I have a container of 20/50 in reserve in case I need to change it.
Hot idle oil pressure is only about 10psi.

Hmm. That figure is worrying. Are there any noises coming from the engine like banging noises? It might be on its way out if the oil is definitely 20/50.

Then again, if this has only just happened it might be something else, as the oil pressure tends to fall gradually over a longer period of time as the engine wears out, thus giving you plenty of notice for a rebuild.

I would take it easy and perhaps throw in a can of Wynn's Super Charge oil treatment, STP or similar.

I can't see the hot weather causing the oil to thin out that much!

That is worryingly low pressure.....but with careful driving I'm sure it will soldier on for a good few thousand miles . However - I would start looking for another engine at the right price........

The engine runs very quietly considering its age with no rumbling or knocking.
As this is the first chance I have had to give the car a decent run since I bought it last October it is the first time that I have really run it up to full temperature so I am hoping that the oil in the sump is too thin a grade and that a change to 20/50 will improve matters. I intend to convert the filter to the spin on type at the same time as the existing unit is weeping oil as well.
Cold oil pressure was over 50psi so i am assuming the gauge is working accurately.
On returning home the engine seemed fine and the car didn't overheat but the oil that was escaping from the filter housing was very thin and watery.

Can't do any harm !

Sounds like some plonker may have put 5w30 in it. I'd get some top grade Asda 20w50 in asap

ive just been to azda their 20/50 is now £16 gone up double

What about the oil pressure, your blood pressure is a different matter

dalebrignall wrote:ive just been to azda their 20/50 is now £16 gone up double

Must be good stuff then

Twice as good as before........ Wilko is still reasonable - but for how long........

Drained the old oil from the car this morning - it was very thin and pretty black.
Replaced the original bolt through type oil filter which was leaking badly with a new spin on conversion kit from ESM and refilled with Unipart PRO M 300 20W/50 oil which I found very reasonably priced in The Range and fired up.
Startup pressure was 60psi, hot running pressure was 40psi and idling pressure was just under 20psi. Looks like it was definitely the wrong oil and I suspect muppetry by the previous owner coupled with a partially clogged filter.
Glad that little scare is over and had great fun poodling around the town today.
Just got to fix a leaking heater control valve ( thought it was the bloody head gasket!) throwing water all over the bellhousing and fit a set of flashing indicators and we'll be good to go. [frame][/frame][frame][/frame]

Excellent result.
Tip: Fix your valve rather than buying new - You don't get that level of quality anymore. They strip apart quite easily and you will find seals and collets which can be found on ebay to suit.

Thanks Sir, I will strip it down and see what falls out!

Hot running 40 psi is not good (barely adequate) - but it will be 'ok' for a while......

bmcecosse wrote:Hot running 40 psi is not good (barely adequate) - but it will be 'ok' for a while......

Manual quotes 30-50 psi so I'm happy with 40

Which 'Manual' is that?? Should be 60 psi - but your 40 will be fine as long it stays up there when properly 'hot'.

Haynes manual quotes 30-60 psi hot running with 60 psi opening the relief valve.
10-25 psi idling and 60 psi cold starting pressure.
As I said the car is running at normal temperature with just over 40 psi reading on the gauge and idling at around 20 psi.
With later cars having just a warning light which comes on at below 8 psi how do you know what pressure you are running at without a gauge and if it's OK to idle with the warning light flickering surely it must be safe to drive with the light out above 8 psi or am I missing something?

Aaaaaa HBOL!! Haynes Book of Lies.....as the Mini lads know it. You are correct of course - the oil warning light is set far too low to give any kind of protection to the engine. When it comes on - it's much too late...... It really should sit on the relief valve when hot - but don't worry - it will soldier on for many a mile at 40 psi..... My own engine (very far from new) sits at 70 psi (the relief valve is lightly packed up) almost all the time - except when being thrashed on a hot day when it will fall away to 60, but fairly quickly recovers to 70 with a bit of more reasonable running.