I drove my mini to work this morning and checked my oil pressure guage only to find that the little needle was way higher than it should be. At that stage i was warming the car up so was trundling along at 2000rpm but even at those low revs the oil pressure was up waaay to high. If i revved it to 2500rpm the little needle would hit the peg (the little peg that is at 0) but hit it on the high side. ie: the needle did a full revolution of the gauge.

Now i asked a few people and they mostly suggested that the oil pressure relief valve was stuck and that i should undo some nut and jimmy the little thingo with some spring with a screwdriver blah blah with that then blah screw the blah blah blah stuff i don't understand... dot dot dot...

Can anybody render assistance and provide pictures of what i should be looking for? I'm at work at the moment and don't have any tools with me... i shouldn't drive the car home with the oil pressure like that should i? My Dad works here also so i could get a lift home with him but he's going away for the weekend at 6pm so i couldn't get a lift back again.

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- Simon -

See the distributor hole midway down the engine? the dark hole with 2 small holes near it. The oil pressure relief plug is the big plug right next to that on the left of it. Can't remember the size of the socket, can only remember that Cooper S's have a 9/16" ball bearing instead of a plunger thingy.

I would not drive with such high oil pressure as that could mean oil starvation in certain places. I think more oil pressure is better than none...?

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Lillee - 1969 Morris Mini K

I would not drive with such high oil pressure as that could mean oil starvation in certain places. I think more oil pressure is better than none...?


i doubt you would get oil starvation .......
but first and formost left of the dissy and up the is a nut should have a dome on it that is were the oil releif vaulve is ... release the nut a few turns and do it up and see if that fixes it ..... could be that the spring has some how got weird ok if it dont fix it remove compleatly and try and fish the plunger out it could have worn and getting stuck in the seat if so you will need a new one
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".

Thanks guys... i should have mentioned earlier that it was a Metro 1275 engine. I dunno if that makes a difference.

I think i'll have to leave it at work over the weekend because i can't see how i'll be able to work on it tonight.

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- Simon -

way too much oil pressure as you`re describing will basically "Pressure Blast" the crank bearings,,,not good as it will wash away the white metal right off bearing surfaces & stuff your donk.

Take the valve & spring out & clean it all, sometimes you may have to cut the spring down (especially if you have a ball bearing in there instead of the std/proper valve)

also check the oil filter (or simply replace it) as it may be blocked & some poeople (more & more these days) are blocking the oil "by-pass" valve inside the filter head,,,so if the filter blocks up with grit or even water can block it, the whole system will heamorage.

YUKKY!!!

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No offence intended here but--> anyone writing a book about minis 30 years ago may not have experienced such worn or stuffed-with components as we are finding these days.

You should put your heart & soul into everything you do.

Ok, i've scored an undercover parking space for it for the weekend behind a security fence. It'll stay there til Monday when i'll have a play during my lunchbreak.

Do you think i could have worn things out by driving it with 100psi for the 10mins it took me to drive to work? You've got me worried now.

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- Simon -

If possible, try another guage....you may not have an issue with pressure, just the guage

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"Show me the Mini!"

I suspect there may be a blockage... i moved the car to the all night spot and noticed when i switched off the engine that the pressure dropped quickly at first and then at around 40psi it almost stopped. It then dropped to zero from there at a much slower rate. It's as if there is a restriction. Does that sound like a blockage or the other problem still?

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- Simon -

Dunno Molly a dicky guage could exhibit just those symptoms....try cracking the oil pressure relief valve if you must and search on what you have to do to use a 9/16 balll bearing.

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"Show me the Mini!"

People call the 9/16" ball bearing trick a Cooper S part, but they never got it stock- out here anyway.

Its main advantage is- it can't jam in the bore like the standard valve can (and does). You will also get better hot idle oil pressure as it seals better.

Its disadvantage is- unless you put a bit of 5/16" (8.0mm) steel rod 40mm long inside the spring, the ball can flick off its seat at times, then you get LOW oil pressure (real low).

If you do this mod you need to cut 3 or 4mm off the spring length as TheMiniMan says.
If you cut too much off, put a couple of flat washers inside the hex cap. Pressure of 60-70 psi hot is nice.

BTW you will need a 1-1/16" (27mm) spanner to undo it.

I've done all my motors, I reckon it's a worthwhile mod.

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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.

Just about to do that mod myself, I'll cut down the head and thread off a 5/16th bolt to 40 mm and use that. I believe I've got to remove the plunger seat as well don't I?

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SooperDooperMiniCooperExpertEngineering

All garage work involves equal measures of enthusiasm, ingenuity and a fair degree of irresponsibility.

NO, MICK, THE SEAT STAYS IN.
Don't use threaded rod, the spring will catch- use a long bolt with threaded part cut off, or a nice shiny piece of round 5/16" /8.0mm steel rod. Must slide inside spring.

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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.

RRRRRRRoger - seat stays in! lolol

Yeah that's what I was planning to do with a big arse 5/16 bolt, just use the shank

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SooperDooperMiniCooperExpertEngineering

All garage work involves equal measures of enthusiasm, ingenuity and a fair degree of irresponsibility.

40mm long is right, that leaves the ball 6-8mm freedom of movement. Heaps...

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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 went to work yesterday to have a fiddle with the mini... I found that there's a buttload of stuff in the way and i can't possibly get a spanner on the nut in question.

I didn't have my camera so i got an old pic of my mini engine and have drawn some arrows on it to confirm what i'm looking at and to explain why i need to go and buy a socket.

Red arrow: Oil cooler hose connecting to the block. This is the first thing that gets in the way of the spanner.
Blue arrow: I guess this is the oil pressure sender for the gauge. This is the second annoying thing.
Green arrow: This is the nut i need to remove???



If i can remove the valve thingo what then? Is there anything i can do to it to fix the problem or will i need to buy something?

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- Simon -