Changing the Oil Pressure Switch

[MColes]

It sure looks like a standard 1098 to me, or a 948 with a different head than it came with. If by 'copper water hose' you mean the one shaped like this...
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...on the left side of the engine as viewed from rear, next to the block, which carries water from the interior heater back to the radiator/cooling system -- this pipe is on the correct side of the engine (and indeed, based on the standard setup of the 948 and 1098, it is impossible to place it on the other side).

Mine is on the opposite side to the photo shown above.

[Fingolfin]

You'd have to find the exception to the rule, wouldn't you, Matt? I'll confess that I'm inexperienced with the broad array of Minors, having only seen three in original condition. For matters like this, in future, I cede the ground to those of you who've seen ten or twenty or fifty.

Nonetheless -- I do stand by what I said -- I just don't see how the coolant pipe would fit on the dynamo side of the block. On the manifold side, there are bolts to hold it, and the radiator hose has a fitting for it. And we haven't proved that anything is wrong with Joe's engine.

[bmcecosse]

There are two versions of the pipe - it's really really not important. Yes - two lights when IGN on - both should go out on starting - and stay out!

[Rasputin]

I have never had a morris with the the water pipe on the manifold side,and I have had a few.

[simmitc]

Although we're deviating a little, the water pipe on the other side is very common. It curves around over the thermostat housing and then down to the bottom hose. I prefer the pipe as shown above - you don't have to remove it to change a thermostat, and you don't have to loosen a head nut to remove the pipe. It is possible to bend it out of the way, but that's not good practice - only a matter of time before the bracket cracks.

Your pipe is fine, and as BMC says, two lights are correct when ignition switched on, both to go out when engine revs.

How's the wiring going?

[MarkyB]

I'm with Rasputin on this, I've seen and owned plenty of Minors but don't recall seeing the pipe on that side.
However, I have reached into the parts box and found the copper pipe after I've torqued the head down I've just taken off the bolts and fitted it rather than modify it to fit somewhere else with hacksaw and drill.
Could the source of this alternate design be people who take the hacksaw/drill route?

[simmitc]

No. As already stated, it was a standard pipe and can be seen on many vehicles. It could be that it was fitted to other variants such as A35, Midget, Mini, etc, and just got moved around; but was quite definitely a standard BMC item. I've got six of them, and can assure you that they are not modified with a hacksaw.

[joeone62]

Thanks

[taupe]

Hi

Ive just checked the parts list and there were two heater pipe arrangements. There was also a version without the pipe and with a connection to the bottom of the radiator.

Series II and earlier 1000 ie the type with round smiths heaters had the pipe fixed to the exhaust manifold. The later cars had the pipe mounted on the cylinder head bolts on the dizzy side. There are pics of the two arrangements in the workshop manual section SS The Heater. You could use either pipe arrangement if you wish as its just a matter of making the correct hose connections

Hope this helps clear this up.

[GheeBhow]

Hi all,

In the spirit of sharing, I thought I'd put down my experience of this here, rather than in a new thread. I'm not far off being a beginner.

The pressure warning light started flickering on the way to work, and came properly on on the way home as the engine warmed up. There was plenty of oil in it, but I had the car recovered just in case, to avoid any damage. I hadn't noticed any clanks or rumbles from the engine, though the exhaust was on its way out so it was hard to hear. On checking, there weren't any strange sounds, so I ruled out big end bearings as a cause (also because my car has a genuine 41K so it's less likely I guess). That left the oil pump and the oil pressure switch as suspects.

I was gearing up for taking the engine out and checking the oil pump, but decided to change the pressure switch first because it was far less hassle. Others on here have said they're very reliable and don't break, but when I spoke to the ESM workshop they said that it was actually quite common for the switches to fail. So I bought one.

There's very little access to the nut on the original switch, which, as others have said is underneath the larger round body of this version of it (my car was built late 1970), but with the distributor cap off and the dipstick out, I could -just- slip a 3/16 spanner on to the nut and loosen it. The replacement switch has a nice big nut which helps enormously. I've just run it up to temperature and the light has stayed off. Which is a relief!

TTFN

[bmcecosse]

Whatever the 'experts' at ESM may say - the original oil pressure switch IS extremely reliable...... But if in doubt - fit an oil pressure gauge, then you will KNOW what the oil pressure is doing - not just guessing at a little light.

[simmitc]

I've avoided this thread so far, but am staggered to see that it has got to (at time of posting) 4 pages This is such a simple thing: when the warning light comes on, it is almost always the switch at fault. The old one unscrews and the new one is fitted in moments, and at minimal cost. If the light remains on, then is the time to look elsewhere. I just don't see how anything more can be said.

[bmcecosse]

I disagree completely.... I won't go as far as saying 'It's never the switch' - but honestly - they very rarely go wrong....... An oil pressure gauge is ESSENTIAL on any A series car........

[mike.perry]

Just to add my contribution, I have both an oil pressure warning light and a gauge. The warning light was on with 30lbs reading on the gauge and eventually it was on permanently. A new switch solved the problem

[simmitc]

Precisely

[bmcecosse]

30 psi switches are much sought after! They actually give a USEFUL warning, and a chance to switch off before serious damage is done. . I also doubt it would be an original BMC fitted switch - which in my experience are deadly reliable. But aftermarket junk.......well, anything goes........ But as I say over and over - FIT AN OIL PRESSURE GAUGE ! It's the MOST useful accessory.

[smithskids]

I must admit I have a gauge for oil pressure but mini spares and other manufacturers make a 22psi oil switch and that is more useful than the standard switch which seems to operate the warning light at about 10psi and thats not much use if it comes on at anything over 2500 rpm.

[JOWETTJAVELIN]

I've avoided this thread so far, but am staggered to see that it has got to (at time of posting) 4 pages This is such a simple thing: when the warning light comes on, it is almost always the switch at fault. The old one unscrews and the new one is fitted in moments, and at minimal cost. If the light remains on, then is the time to look elsewhere. I just don't see how anything more can be said.

Indeed. 5 min job tops. Like the others say fit a gauge for peace of mind and it will give an accurate picture of the condition of the bearings.

Taupe, the S.II had a different radiator to later cars with a take-off at the bottom RH (from driver's seat) for the heater. No copper pipe was used but a long hose attached to the chassis.

[bmcecosse]

And the Mini manages just fine with a rubber hose......ditch the copper pipe.

[chesney]

Series II and earlier 1000 ie the type with round smiths heaters had the pipe fixed to the exhaust manifold. The later cars had the pipe mounted on the cylinder head bolts on the dizzy side.

My '58 saloon has the heater pipe at the bottom of the radiator - not sure if original but I would be very surprised if someone had swapped the rad for an earlier one - then swapped the heater hoses to suit.
Just more to add to the mix