Oil cooler

[Nerys]

I've recently fitted a complete custom instrument panel to my Minor 1000 (1098cc); as expected the oil pressure drops at tick over when the engine is warm but I wasn't expecting it to drop as much as it does (the oil pressure warning light doesn't come on though) so I am contemplating fitting an oil cooler. The parts for the A Series are freely available and not too expensive. The only questions are where and how to mount it and exactly how to plumb it in. My initial thoughts are it has to be mounted between the radiator and the grill slats, as low as possible. The plumbing in would be easiest and cheapest done by simply removing the pipe that runs from the block to the filter; a sandwich plate could be used, which would give shorter pipe runs, but would require cutting a half mood piece out of the chassis leg to clear the filter. Has anyone fitted an oil cooler before or have any other relevant experience or knowledge?

[ManyMinors]

Unless you are driving your car VERY hard I would guess that the drop in oil pressure is due to engine wear rather than simply the temperature of the oil. I rather doubt that an oil cooler would make much difference in this case. My own Minor has an oil pressure gauge fitted and the pressure drops quite a bit - to 20psi or so - when hot and ticking over. It has been so for years but it runs fine and uses almost no oil so I just keep driving it If it didn't have a gauge, I wouldn't know anyway

[philthehill]

Fitting an oil cooler will not cure the problem of low oil pressure.
Your low oil pressure is caused in the main by worn crankshaft big end and crankshaft main bearings.
Replacing the main and big end bearings is a much better resolution.

If you do decide to fit an oil cooler the take off can be at the block end of the pipe that feeds the oil filter and the return back to the oil filter end of the same pipe. The metal pipe between the block and filter is discarded.
Likewise you can fit a sandwich plate and take off and return from the plate.
There is an oil filter adapter/riser plate (Pt No: AEA657) fitted to later 1275cc Midgets that can be utilised so as not to cut the chassis leg.
It is always best to fit a oil cooler thermostat into the system so that only over heated oil is passed to the oil cooler.
Phil

[Nerys]

Thanks for the input guys. The engine isn't worn, in fact it was a new engine in 2013 and when I fitted it with an SU Hif38 carb on an LCB manifold and large bore exhaust I had it set up on a rolling road. The engine peaked at 47bhp at 6100rpm, and this was when it had only done about 1000 miles. Now it's properly run in (about 15,000 miles) I suspect it produces a bit more. As for driving it hard, well yes and no, I have a rev counter and rarely exceed 4000rpm, but note she's only doing 3500rpm at 70 MPH in fifth. I was driving round the M25 on the hottest day of the year and the drop in oil pressure was definitely related to the rise in engine temperature. So I'm a bit more confident now about the plumbing (thanks guys), but if anyone knows anything about the actual mounting of the cooler I would be grateful.

[RobThomas]

You can bit the original filer and add a plate with just one hole that bolts to the side of the block instead of the old casting. Then add a cooler and a chuffin' great big filter.
If you mount the numberplate to the mid level of the bumper instead of underneath then you can stick a cooler below the bumper area.

This one used the original filter casting and pipework but instead of the old filter can hanging down it had a home-made plate that took oil out to the big filter and then back. Not elegant, but functional.[frame][/frame]

[bmcecosse]

You do not need an oil cooler on a low spec engine like that. Your power output with the mods you have is low - a perfectly standard 1098 should make 48 bhp! Are you running a high temp thermostat? Is the water temperature high? Are you using 20W 50 oil? As others have pointed out - low oil pressure (what is it at 50 mph in 4th gear?) is caused by worn bearings and oil pump... How 'new' is the engine - fully rebuilt with reground crank /rebored etc -or just 'refreshed' with new shells/rings etc ??

[oliver90owner]

I note there is no mention of pressure relief valve leakage. It should not occur on a recently new engine, but it is often overlooked as a possible reason for oil pressure reduction. I've perked up the oil pressure on several Landrover (high mileage) engines over the years.

[IslipMinor]

As above, with the revs that you are using, the oil temperature is extremely unlikely to get to the point of needing cooling, even on a hot day.

What is the oil pressure at idle and say 3,000 rpm when 'hot'?

[bmcecosse]

Of course -it all may just be a low reading oil pressure gauge. Extremely unlikley to be leaking relief valve........

[philthehill]

For a variation on a theme re oil cooler - why not use a water/oil intercooler.
The water/oil cooler in the link below can easily be adapted for use with an 'A' Series by mounting the water/oil cooler on a flat alloy plate with the individual oil hoses connected through the back of the alloy plate to the block and filter unions and the water hoses to the 'A' Series coolant system
It would be a variant to the water/oil cooler as fitted to the MG Metro Turbo and various Ford performance cars.

http://www.ebay.co.uk/itm/FORD-FOCUS-1- ... 2510306425

The MG Metro turbo water/oil cooler is no longer available but adaptions can be made to serve the same purpose.

You also have the added advantage of an additional and more choice of oil filters.

Phil

[IslipMinor]

Phil,

We have the MG Metro water-cooled oil cooler on our 1380, and it keeps the oil temperature at around 95/100°C for road use and around 115°C on track days. The oil is Castrol full synthetic, so well within its normal operating temperature range.

The fitting is a bit of a problem though, as the standard MG Metro oil filter head is too long to fit without the oil filter itself fouling the chassis leg, and the standard Mini type spin-on filter head does not give enough room for the water-cooled body to clear the block.

The solution has been to use a Mini/Midget filter head that uses the long studs and a 3/8" spacer between it and the block, as using the standard Mini type oil filter head with the 'thin flange', gave problems with the head cracking. The spacer gives clearance between the water-cooled bit and the block, and also between the oil filter canister and the chassis leg.

[bmcecosse]

On that low power engine - there is no need for ANY form of oil cooling....

[MikeNash]

A few thoughts, Mr Nerys.

You will only get to the bottom of this with an oil pressure gauge (preferably by far a mechanical one rather than electric) and an oil temperature gauge (again non-electric); there's no substitute for real numbers. And each engine is different.

As an example I've been running for years a standard 1098 engine in a Traveller (don't forget these are heavier and less aerodynamic than the saloon) and when doing 60-65 mph (true, measured via GPS) for long spells on motorways, say for 60-90 minutes up and down the long shallow hills you meet, I'd get the water up to 90-95C (a 89C thermostat is fitted) and the oil up to 90C as well. Occasionally when getting close to 70mph for spells (10-15 minutes) I'd see the upper nineties for both but I never ever got over a 100C for either. All this was with an elderly engine that couldn't get above 42 psi oil pressure in these events and did around 150 miles to the pint of oil, so the temps above were often with the oil level getting down to the "min" level. A quick stop at a service station on these hot runs would see the oil pressure fall to about 8 to 10 psi. (The air temp on some of these runs was 23-25C. And my temp gauges were checked against a reliable mercury thermometer.) All this is with Wilkinson's 20-50 grade oil.

So I don't think you should rush to an oil cooler, but if you go that route DEFINITELY fit an oil temperature gauge for you'll find that for much of your running about the A series engine are naturally so cool they need oil heaters! Typically, for much of the winter you won't get above 50-60C which is far too cool. So for that reason I support Phil's recommendation for the Ford Focus's water cooler/heater solution. (Indeed, following his tip I've just e-bayed one for £16.99!)

Regarding the 1098's power, I suspect that the oft quoted figure of 48 HP was most probably from a especially selected good 'un set up by experienced engineers; whether it had a full exhaust and silencer or a standard air filter, dynamo, etc is anyone's guess. I'd be surprised if the average home owner sees the full 48HP - more likely a few down on that. So if you're putting 47HP down on the road I think you're doing good, and if you're only losing 5% through the drive train (and that'd be good) your engine's putting out about 50HP - not bad in the real world.

Regards, MikeN.

[Nerys]

I've been taking on board everything everyone has said and been doing a bit more research. First of all a few clarifications, the engine was a new one fitted by Charles Wares Morris Minor Centre with a new oil pump and new water pump, this was fitted in April 2013. The engine is clearly in rude health, no unwarranted noises and performs in a way that Morris 1000's aren't supposed to! If the main bearings were worn then so would the oil thrower be worn with the resultant excessive oil consumption, I know all about that, that's why a new engine was fitted in the first place.

In normal running the oil pressure is 48/50 psi dropping to 23/25 at tick over; however when the engine is very hot, particularly on a hot day the normal running pressure drops to around 45 psi but at tick over drops to around 2/4 psi although the oil pressure warning light doesn't flicker at all. The instruments were only fitted in spring of this year and note that the oil pressure gauge is an electrical one. If this low oil pressure was accurate I would have thought that the bearings would have been damaged long before the instruments were fitted. So I am now being drawn to the conclusion that the fault is with the gauge or it's wiring. If there is a high resistant contact somewhere in the connection is it likely that this cause a false reading at low pressure?

Returning to the original query about an oil cooler, it is true that an oil cooler shouldn't be necessary, but they are always a good idea with any engine to maintain the oil at its optimum pressure and so maximise the engine's longevity. It's similar to saying servo assisted disc brakes aren't necessary, no they are not, but they are a good idea!

So original query, where to fit the oil cooler radiator? I've one suggestion so far, thank you, but moving the number plate and mounting it below the bumper undoubtedly would work, but aesthetically is unacceptable to me; any other suggestions?

[MikeNash]

Dear Nerys,

Those oil pressures when hot are SERIOUSLY bad! So I think you MUST get the pressure gauge checked. Personally, I only trust the mechanical direct reading variety and am suspicious of the electric type, but more expert commentators will be along shortly. For comparison, my engine I describe above was a 1966 BMC "Gold Seal" implant that had some 100,000 miles experience of variable servicing in its life and had now got down to about 120-150 miles to the pint of oil - hence it being pensioned off. And even though it had dropped to 42 psi oil pressure when very hot it made no untoward noises; the A series engines are tough and reliable so noise is a poor guide to overall condition! And your engine, even if such bad shape to have such low oil pressures, will still go very well.

What oil are your readings obtained with? SAE 20-50?

Regarding the purpose of oil coolers, in my opinion they are to cool oil that's too hot (say reaching 95C or more) and NOT to increase oil pressure! That is best done by bearings in good condition and your readings IF TRUE indicate otherwise. That said, I think too much is made of a need for high oil pressures and for an ordinary life for a Morris your low pressures would still give satisfactory running for a long time. But if you wish to drive it hard then something needs to be done.
Please check that gauge first, regards MikeN.

[IslipMinor]

The first thing I would do would be to fit a mechanical gauge and compare the readings with your existing electric one. The 2/4 psi hot idle is way too low, and also well below the pressure when the oil pressure light comes on ~7 psi. Does the oil light come on before starting the engine? And go off as normal?

The second thing would be to check the wiring for your electric oil pressure gauge. What do the instructions say about how it should be wired? Should it take its feed from a 12v fused battery supply, or from the 10v 'stabiliser' that was fitted to 1098 Minors at the same time as the black faced speedo? What has actually been wired in?

Oil should run at 80-100°C as a 'normal' range. Cooler is not good, as the moisture in it will not be evaporated - the typical sign is mayo in the rocker cover. If you have that, take the car out for a good 20 mile run at 60-70 mph on the motorway to get the oil properly warm and disperse some of the moisture. More than a sustained 100°C is when thinking about fitting an oil cooler comes in.

Finally, what is the oil pressure when starting from cold? With cold oil, I would expect at least 70 and up to 80 psi.

[RobThomas]

Wot he just said!

I have some Penrite oil which is rated 20W60 so that might be an option to 'up' the pressure when hot. Shelsley Light is the name on the can.

Wrt the pressure switch, it may well not come on until almost zero. I bought some switches that come on at a much higher pressure so you know well in advance that you are about to run out of pressure. 7psi may well be a little late for an engine but perhaps Morris expected engine bearings and pumps to cr4p out quite often?

https://www.minisport.com/uprated-oil-p ... 59-96.html

[Nerys]

As before I've read all your replies and taken them on board. First of all to clear up a couple of things; apologies for the Freudian slip in previous post, I should have typed "optimum temperature" not "optimum pressure"; Nerys is currently running on SAE 10-40W (the primarily approved grade in the handbook) but will be changed to SAE 20-50W and her next oil change due later this month. The gauges are a bespoke set made to my (aesthetic) requirements by Speedy Cables who bought out Smith's.

Just to re-iterate it's now quite clear (to me) that Nerys's engine is hale and hearty, in fact far better than average, and that the low pressure readings are a red herring in terms of her health. As I mentioned the gauge is electric, it has been wired in as prescribed by the manufacturer i.e. the supply is 12v (as far as I know 10V is only used with later fuel gauges (part Nos beginning with "BF/") and the water temperature gauge). It's not, for practical and financial reasons possible to replace the gauge with a mechanical one or fit an oil temperature gauge.

However the supply side of the wiring is a temporary connection until I can fit Nerys's new fuse boxes, so at present doesn't have its own separate supply protected by a 3 amp fuse. This is why I am wondering if there is a poor connection that could be the root cause of the problem. So until Nerys is running on SAE 20-50W and I have sorted out the gauge's electrical supply we can't really move on. I will provide an update when I can.

In the mean time thank you all for your comments, at least I have sorted out (with your help) the plumbing and the fact that a thermostat would be essential. if anyone out there has fitted an oil cooler, please let me know where you sited it (apart from under the bumper and moving the number plate.

[Nerys]

Follow point of interest; just noticed that although the recommended oils in the handbook are mostly SAE 10-40W, one is even SAE 10-30, with SAE 20-50W being listed at the bottom of the table as an approved alternative; in the Workshop Manual all the recommended oils are SAE 20-50W!

[philthehill]

Oil pressure readings are not a matter of red herrings but an important part of an engines makeup - therefore I personally would get the oil pressure readings confirmed by using a calibrated mechanical or known oil pressure gauge.
You do not have to install the gauge - just temporally connect into to where the oil pressure switch is fitted.
Until you know the oil pressures everything is just conjecture.
There is nothing like knowing the true facts for peace of mind.
The use of 20W50 grade engine oil is the preferred oil to be used in an 'A' Series.
Phil