I use to have good oil pressure and suddenly I now have very little!!! On idle I am as low as 0!!! I rev, it goes up, but on idle.... :shock:

The oil level is good, not blowing any smoke, oil isn't pouring out anywhere. Just the oil pressure has suddenly dropped to a suicidal level.

Any ideas on what has gone wrong? I have heard that it could be the big end bearings. Any other ideas? Suggestions on what to check?

G

is it making any funny noises?? maybe your gauge has gone bung?? check the oil line to it, may have a crack.

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1974 Moke - 998cc
76 Clubman B16a2 Vtec AWD Turbo 12.9@105mph
https://www.youtube.com/watch?v=V9PW49e1hYs

could be the filter is blocked and bypassing.

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the world is a book, and those who do not travel read only a page
66 Mini Minor sponsored by http://www.lifeonthehedge.com.au/ The Dog Harness Specialists
It was a pleasure ausmini. I'll miss all you misfits and reprobates

...or could be a bit of crap caught in the oil pressure relief valve not allowing it to seat properly.

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Who's MadMax?

Hey, that is what I was going to say!

I'd nearly put money on it!

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Who's MadMax?

I'd agree on the above....change the oil filter and true and find a strong magnet to to put on its side....When was the last time you changed the oil filter.
Hode from the the send it, is not the problem as it will always have the pressure but the gaudge may do.....
Change oil and oil filter and let us know what happens
I'm thinking the filter

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Stop Licking the Dog...I Don't Care Who Started It

Thanks all for responding. Finally got a chance on the weekend to look for the problem. It did turn out to be a struck oil pressure relief valve.

An easy fix in the end. A worry when people start talking about bearings and stuff.

Great technique to remove a stuck valve was mentioned by I_AM_THE_WAHL about using a dyna bolt. Worked a treat! I found a 12mm bolt perfect. The 10mm a bit small. A cheap dyna bolt works. You don't need an expensive steel one.

I am going to do a Doc upgrade and go for the ball bearing replacement. The old valve has quite a few marks running along it.

I found an interesting article along the lines of Doc's fix which makes the relief valve adjustable - http://www.niksula.cs.hut.fi/~mdobruck/siililand/mini/diy/7/valve.htm

Mind you, the adjustability is debatable.

Thanks all for your help. One more happy mini on the road!

can't quite remember the exact details but someone once told me that its better to leave the standard pressure relief valve in there as a kind of early-warning-system. the theory was something like: when it gets stuck it can indicate something wrong (bits of metal floating around?) and you can fix it before (much) damage is done, but with the bearing-mod it would push its way past and you'd never know

If it jams open, you can ruin a perfectly good set of bearings! I'll take the ball.
Bits of metal will finish up in the filter, or on the sump plug eventually, if they go thru the relief valve

BTW.. did the Cooper S ever have a ball fitted ex factory, on not? People overseas say yes, but the 2 1275S motors I owned (a MK1 & a Mk2) both had the stock relief valve.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

no ball bearing in mine... not that it proves anything - may have been changed

Mine does not have a ball.

I don't think that any did!

The most important race of the year was Bathurst and all cars had to run standard. You also had to be able to prove what was standard.
So if the Cooper S came with them standard then the parts books and the workshop manuals should show it.

Ah well.. anyhow, MiniSpares UK advertised `Cooper S ball and spring' in their catalog.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

i got one cause graham russle said they are better ... the ball bearing that is
so fool me for listning to GR
makka

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Anonymous moderation means the agro that is built up towards the mods isn't aimed at an individual (fewer "Makk" attacks). Less stress for mods means less moderator "retirements".

GR is no fool... the ball is better as it cannot jam.
Mine has been perfect since I put the bit of 5/16" rod inside the spring. At idle hot, it's got around 30psi, at 2500 hot it's got 75, above that 70.
Motor's now done 45,000 miles since I rebuilt it, and it still gets revved to 7,500. I use a MiniSpares Sureflo pump...

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.