Suitable oil

[111Robin]

I notice that 1071S is based in Oz so maybe 10/60 is ok there for prolonged high temperature use ?. For UK temperatures though I think it would be like trying to suck treacle through a straw !.

[johnv]

Do horses wear rubber shoes now?

[Andrew1967]

They don’t in Norfolk, but we are known for being a little behind the times

[Polarsilver]

I remember that Duckhams Q20/50 back in the day would also produce salad cream in the Rocker Cover never could get rid of that stuff .. if we need any Salad Cream today i go to Tesco

[spoon.450]

I’d guess that any 20/50 oil that we can buy today is a better spec than the stuff we ran our cars on in the 60’s 70’s and 80’s………correct me if I’m wrong

[Allen Brzeczek]

Returning my S to the road after years in hibernation I used a modern semi synthetic, Despite the engine having been freshly rebuilt presumably with the detergents/additives various gaskets soon showed signs of seepage.

Needed to remove and sort unrelated issue with the engine and have used Duckhams since. Car is not a museum piece and is driven enthusiastically and enjoyed, with regular oil change every 3,000 mls have had no issues. Still retains original oil pressure and no ¬salad cream"

[peasantslife]

Sorry I feel I have to throw in my two penneth worth. I feel this is like blind men playing darts and rather illustrates a fundamental lack of understanding amongst the vast majority who consider themselves 'petrolheads' at whatever level.
Now I certainly dont have the magic answer perhaps being hoped for, but I do know that if we consider 'lubrication oils' in general as a novel, then automotive engine oils would hardly justify a chapter, yet they are arguably the most complex component/part number fitted to a new engine! (and in service the most consistently abused).
Simply thinking the viscosity index is the be all and end all is like suggesting all black shoes are the same. A wellington and a sandal could both be equal in that measure but I'll venture the second would not suit marching through a yard of pig muck!
Infinitely more important than the viscosity is the add-mix of property enhancers. and that in itself varies around the world dependent on various factors. Lets just assume Castol offer a 20W50 GTX globally. Its not the same product in all markets! In the America's it could be from Venezualan crude, Europeans likely would get Middle eastern and Asia Pacific potentially Indonesian. Each crude will be cracked differently to suit its market, and the add-mix will differ dramatically giving each product a notably different signature. eg US/Canada have historically had very short service life - even when using a globally supplied motor. Europe today is quite content to go to 20k miles or even greater service intervals. Then we need to look at emissions levels, where standards are still low-ish likely to find greater (than zero) Zinc dithiophosphate ZDDP (I had to look up how to spell it!)
ZDDP is a cat killer so where regs are harsher its not part of the add-mix at all - but it has particularly strong anti wear characteristics, which a mini needs as it cant employ a hypoid grade which will have much higher shear properties....but lower oxidation resistance....

To be honest I have no idea what exactly BMC actually specified, or indeed what standards were being employed in the late 50's/60's Longbridge, API grades help to define what additive mix is applied to your base grade oils. That is what you ought to be looking at! ....Just taking a look at the API Grades looks like SC/SD/SE would have been appropriate for 1960's mini's. I dont actually know which brands offer those grades today...And why use a multigrade at all?? If you are a Drive it Day to end of Sept user you will never see the benefit of your 20W....so just buy a straight grade 50 (if you can with the API SC/SD/SE also on the container)
Older engines may not like 'modern' oils, manufacturing tolerances have moved a country mile since A series started production, Bearing materials have evolved to share nothing in common, Similarly so have the metals and plastics used in modern engine designs...
I dont have the universal answer, but its not even on the dartboard with the current posts - even my Rover VVC motors (only 20 years old) are now best served with what would be called a Diesel Spec oil today....

[spoon.450]

So….what are we saying is the best oil for our minis…..??
I’ve just put some 20/ 50 Napa in mine….

[Robbie224]

I had a E reg land rover once. Was a old 2.5 naturally aspirated diesel engine every book and most forums always recommend ATF OIL automatic transmission fluid in a manual gearbox because in early days of land rover production that's the best oil that was available. Eventually land rover brought out a upgraded manual gearbox with recommendation to use a MTF manual transmission fluid. Both gears boxes weren't greatly different even though any one with the original gearbox was still recommend to use a ATF oil but in fact the older style gearbox would run much better with MTF in it. Basically over time oil technology's had change so MTF was infact a better oil. Seems to me classic mini engine are going through same possibly with old out of date oil recommendations still being used. I'm putting Millers motorsport CTV mini 20w50 semi synthetic in my GT.

[111Robin]

Let's not get overly scientific about this. The only indicators you have of how your chosen lubricant performs are oil pressure and consumption. If you really want to know then fully measure and inspect everything before build, run it for say 10000 miles then strip and repeat the inspection then repeat for a dozen other oil grades and brands then tell us all what the best is ((and repeat for all regions of the world). Alternatively use a quality 20w/50, change it every year and forget about it like most of us have been doing for 50 years without having to rebuild our engines and gearboxes every year.

[Exminiman]

Let's not get overly scientific about this. The only indicators you have of how your chosen lubricant performs are oil pressure and consumption. If you really want to know then fully measure and inspect everything before build, run it for say 10000 miles then strip and repeat the inspection then repeat for a dozen other oil grades and brands then tell us all what the best is ((and repeat for all regions of the world). Alternatively use a quality 20w/50, change it every year and forget about it like most of us have been doing for 50 years without having to rebuild our engines and gearboxes every year.

Have to agree....

Only caveat I would add is checking level of ZDDP, I am in no way qualified to say this, but pretty much every thing I have read says how important it is in a flat tappet engine. Apparently there is no modern replacement and main reason it was removed from modern oils is it is potentially damaging to cats (no dog jokes please).

Still a bit baffled as to why 10W/60 is better than 25W/50, as far as I know these numbers just refer to the oil viscosity (weight) at two temperatures - the lower number (W for Winter) at 0 degrees C and the higher at 100 degrees C.

So surly, if that is correct, then 60 will be thicker at 100 degrees C than 50 and presumabley correspondingly thicker through the temperature range, slowing oil flow, increasing resistance etc. Why is that a good thing?

I can see that 10 could be a benefit in a cold climate, for easier starting.

My A35 factory manual quotes mono-grade 30 weight oil........which makes sense of 25W/50

Please chime in and correct or shoot down anything, especially is ZDDP really that important?

[snoopy64]

I’m just using a ‘classic mini’ oil with no thought whatsoever on the basis that after 85000 miles the damage is already done and the 2000 miles a year I do is insignificant.

[Peter Laidler]

Hey......., just a minute..... Robbie 224, you started this 4 page discussion thread with a Q about oil and now, 3 pages further on in the discussion, you've answered your own question that you started with......

You use what you want to use. Or am I missing something

[Robbie224]

Good point Peter

[111Robin]

I think you'll get the gist, there's never just one answer to these questions however you will get a lot of advice, you need to figure which way to go

[mk1]

I never use anything but this.

http://www.minispares.com/product/Class ... o%20search

image.jpg

In everything from my 40hp 850 through to my 150 bhp Supercharged 999 & everything in between.

Never had any issues at all. GREAT VALUE!

[gs.davies]

I never use anything but this.

http://www.minispares.com/product/Class ... o%20search

image.jpg

In everything from my 40hp 850 through to my 150 bhp Supercharged 999 & everything in between.

Never had any issues at all. GREAT VALUE!

Good to know - I've got a can of it waiting to go into the engine once it's ready to fire up. Absolute bargain with an oil filter too, and it's high in ZDDP.

[surfblue63]

I never use anything but this.

http://www.minispares.com/product/Class ... o%20search

And its even better value if you buy it with the filter

http://www.minispares.com/product/Class ... o%20search

[Allen Brzeczek]

The comments and various technical explanations are very interesting. However, while have no doubt what so ever regards the "suitability" of Castrol 20/50 but as the owner of an S which is enjoyed and driven enthusiastically my personal choice is Duckhams which as I understand, despite Castrol sponsorship was on occasions the choice of some of the Works teams

[Peter Laidler]

Works team(s) using the oil of the sponsors opposition. Just consider the absolute team (and BMC) destroying ramifications if that were ever established as truth.......