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I don't know whether anyone has talked about this in the past...

I was reading an article in a motorcycle magazine about engine oils.
It stated that motorcycle oils differed from car oils due to EP (extreme pressure) additives, because the engine and gearbox are combined. My interest was sparked, as I know another vehicle that shares its oil between engine and 'box!

I sent an e-mail to Castrol UK, and got the following reply:

Thank you for your email - Interestingly I have just done an email on the same subject to a chap rebuilding a Cooper.

I suggested that for normal everyday driving that the Classic XL 20W-50 would certainly be suitable and best for running in purposes, but if you have a preference for the enhanced performance and protection of a full synthetic, then the EDGE 10W-60 car oil, or as you suggest the Power 1 Racing 10W-50 - being designed for the combined use of engine and gearbox of modern 4 stroke motorcycles, would be worth consideration.

Early engine oils that were around with the advent of the Mini would certainly not have had any special EP properties, so I would suggest that the design of the gear train in the Mini would be such that a low EP oil ( normal engine oils ) will be quite satisfactory in normal everyday running.

I hope that helps


Of course, there is also the Castrol Act>Evo 20W-50 mineral motorcycle oil - possibly a better alternative to the Classic XL 20W-50 for running in also


Now, I want all the protection I can get in the engine/'box, so I will be running Motorcycle oils in the future.
-I did also mention that the difference with the Mini, was the synchromesh in the gearbox, but this isn't a problem.

Hope you find this of interest, and it gives you something to think about?

andy

the bigest flaw is that motorbikes have dog boxes, so are suited to the oil.

running piss thin oil on a mini with a syncro box will quickly end in disaster as the oil is too thin for the baulk rings etc to work correctly and will very quickly start to show problems.

ive never seen anyone enjoy extended gearbox life by choosing a thinner oil than 20/50

i remember my old mini nut boss telling me back in the 60's most mini men run duckams the green colored one they reckoned the oil pressure was always slightly better when using it.

My old boss reckoned he always used duckam's then one day he changed to castrol as that was all he had at the time
on the very same day he was tearing up a hill in third gear and heard the big ends picking up.

Probably just coincidence but he always swore by duckams there will be better oils these days as that was over 40 years ago lol

The original Owners Handbook quotes 10W30 or 10W40 for all models operating above minus 18C!

Just sticking a 20/50 oil in doesn't guarantee the engine/gearbox will last.

We all know oil is a complex field (oil field! -sorry!), so we have to select the correct oil for the application.

I always ran 10/40 in my old Cooper S (good stuff, not supermarket rubbish) without a problem. -And that was kicking out 104hp at the wheels, so it got some abuse

Running oil that is too thick will also cause problems (probably not to the baulk rings, but the selector forks instead).

In the day (in rallying anyway) Duckhams 20/50 always seemed to have the edge, even over equivalent Castrol, in keeping oil pressure up etc.
I know of a multi Mini team on the RAC Rally in the 60s that contracted to use Shell and ended up draining it (as near water consistency, over a street drain as you did then....) and re-filling with Duckhams 20/50.

All accademic now, as Duckhams 20/50 has disappeared and over a large number of recent years was said not to be the same spec as back in the day.

In a similar vein, -I know that F1 teams were using Mobil 1 in their cars when it first came out. No matter who they were sponsored by. -They emptied their sponsors oil cans, and filled them with Mobil 1....

Millers

I have never had any problems with good old cheap & cheerful 20/50 for the last 30 years, I'm not planing on changing in the near future.

I have run R40 in most of my competition cars and that's been fine too.

I have heard & know of far to many horror stories from people running pi55 thin oil in A series engines to experiment on my own.

And that was kicking out 104hp at the wheels

At the wheels??? What had been done to it?

I agree with the comments about thin synthetic oils, and also, more to the point, what gain do you perceive from running it?
The engine was designed to run on non-synthetic 10w40 with clearances and materials that suit this type of oil. In my opinion it makes sense to run an oil suited to the engine design. Having said that I don't
I use millers 20w50 CTV which us a semi-synthetic oil designed to work in a shared engine and gearbox. I spent a long time talking to the millers guy at the autosport show and this oil was specifically designed with shared transverse engines in mind, for example minis.
I haven't done enough miles to validate the choice yet.

I don't think there is any substitute for changing it regularly though.

A bit OT, but what is the truth about R40. Could the "old" oil be drained, the filter changed and then R40 added? I've heard that they do not mixed, but Castrol say that they "should not" me mixed. Truth?

I ran CTV and had sporadic drops in pressure when the oil got hot, ie special tests flat out in first. Swapped to R40 and never had an issue since.

The advice I got from Castrol on R40 was that it should be used on a fresh build or should be used to flush out the old oil by changing it 3 or 4 times in quick succession (ie run engine then drain). Stripping the eingine is porbably cheaper!! I believe it emulsifies if mixed with a non-castor based oil.

Hi sclemow,
Basic engine spec: 73mm pistons, SW10 cam, twin 1 1/2" SUs. Rod Taylor at Southam Mini Metro Centre worked his magic on the head, and did all the machining work / balancing.
I can recommend SMMC. Great guys. The engine is incedible, idle is below 1000rpm, and pretty smooth, and after about 2500, it pulls like a train.

I got involved with oils in a previous job. The semi-synthetic oils in the UK can be different to semis in Europe. To qualify as semi-synthetic in UK, the oil can be 'hydro cracked' (a sort of heat treatment), and not actually contain synthetic elements.

I would say all of the oils from the well known companies are better than anything that was available in the 60s (some of the cheapy 'supermarket' oils are actually re-cycled/reclaimed! )

Oils are one of those things that everyone seems to have a strong opinion about. I know I do
I always used to choose oil based on the API rating, but after finding out about the modern blending to suit catalysts etc, I've had to think again.

A thought: With the increase in the % of ethanol in petrol (5% now, increasing to 10%), would it be better to use Castrol R40? Being vegetable based it should be more compatible with ethanol?
Plus of course, it smell great...

Basic engine spec: 73mm pistons, SW10 cam, twin 1 1/2" SUs. Rod Taylor at Southam Mini Metro Centre worked his magic on the head, and did all the machining work / balancing.
I can recommend SMMC. Great guys. The engine is incedible, idle is below 1000rpm, and pretty smooth, and after about 2500, it pulls like a train.

Fair enough - I would have put that engine spec at a lower power than that (It's similar to mine). But all the rolling roads are different!

S

im using shell rimula x truck oil ,10/40 , it had the highest zddp i could find ,10 quid a gallon .
oh , 230bhp at the wheels .a series.

robert wrote:im using shell rimula x truck oil ,10/40 , it had the highest zddp i could find ,10 quid a gallon .
oh , 230bhp at the wheels .a series.

I use Comma Sonic 20/50, highest zddp content, I could find of the 20/50 oils available with 1500 ppm.

Speaking as someone who did many years ago swap from mineral to Castor based oil without a fresh rebuilt, I flushed as was suggested above & didn't suffer any terrible effects while the engine was in one piece, but when I came to rebuild the engine there were very hard thick deposits of varnish like stuff & masses of sludge in all sorts of nooks & crannies in the engine. I have never seen this before or since so can only assume it was something to do with the "forbidden oil switch".

Of course, given the price and availablity of R40 I do tend to drain & filter it and then mix it 50/50 with new stuff before putting it back in the top.

Isopropyl alcohol is the best solvent for castor oil, if you're cleaning stuff out. I'd also use a drop of fairy liquid in there also.

Now, for cleaning the engine out of multigrade and the associated gunge, the best stuff is cellulose thinners, or pure toluene if you can get your hands on some.

I would rather avoid doing a mineral>vegetable oil swap without having the engine to bits, HOWEVER, I'd also hesitate at running castor oil without a reduced pressure sump. Water in the oil from blow-by is the biggest enemy of castor, you then get the associated acids build up from combustion and then they encourage various chemical reactions resulting in gums and waxes.

The full race 1430 is running castor and I wouldn't have it any other way.

This topic has come up many times on the Ausmini forum.

I did a fair bit of looking into this, and there's one area where modern oils may not be the ideal choice.

In recent years (after the SG specification oils) they started dropping the ZDDP component in oils. ZDDP is one of the main components they add to prevent wear when the oil film can't be sustained and you basically have metal-to-metal contact. This is especially relevant for us as we have flat-tappet engines and shared-oil gearboxes - lots of potential metal-to-metal contact.

They've dropped the amount of this additive because modern engines have much less use for it, as well as it shortens the lifespans of environmental control items.

So when looking for oils go for older spec like SG, which still has decent levels of ZDDP.

I've run "cheap and nasty" oils in minis for years, no dramas, seems getting the right specification & changing regularly is more important than anything else.

cheers,

Jacob

In the 60's and 70's I used to use Duckhams 20/50 and a can of STP every 3,000 miles, worked fine with no problems.