Best oil to use

There is no consensus of course. However, good quality multigrade seems to suit the bike, either synthetic or mineral though some prefer a straight 40. There are pros and cons when it comes to vegetable-based oils - another topic perhaps. All that can be said is that oils are rather better than they once were. Gordon.

I have a little book of Commando tips that says that 10/40 oil is only for H*nda's profits!

20/50 was always fine but these days I find that straight 40 is good for all year round in the UK. No problems with this in allNorton's of mine. Just remember to select a light detergent when using a spin on/off filter.

As the climate cools, we might need to consider straight 30 for all year round riding. Hope not.

Since nowadays, very few motorcycles are used as a primary form of transport (particularly classic bikes), few are likely to excede 5,000 miles per year.

With an annual oil change, no appreciable wear, or damage, is likely to occur using Halfords Classic 20/50 oil. Lets face it (with the exception of rotory and the 961) Norton engines were only updates of 40's designs, hardly "Hi-tech".

As mentioned in other threads, I use Morris's 20-50 in winter (most of the year up here), SAE 40 in summer. Gordon.

If you have access to backcopys of 'Roadholder' there are a copple of articles on New oils for Old Nortons. With regard to multi-grade versus monograde, multigrade offers better low temperature operation with no worse high temperature operation. By the 1960's most UK manufacturers were specifying either a 15W40 or a 20W50 grade.

The argument around classic versus modern runs as follows, classic oils offer no proof of performance at all or claims made against obsolete specifications.In other words 'trust us ,we know what we are doing'.

Modern oils are tested against the most rigorous of conditions in tests which are statistically monitored for their ability to discriminate product quality.

Their being little price difference between Ancient and Modern, I go for the modern.

Synthetic base stocks offer the oil formulator two advantages over mineral oils, firstly because of their better low temperature viscometric properties, you can make a wider range oil, secondly they are more responsive to anti-oxidants and thus less prone to deposit formation and viscosity increase under high temperature operations.

Bad luck if you do have a Castor based oil in it now. These are not really intended for long service use and cause problems with gum and varnish formation. Advise is to ditch the R and flush with a good flushing oil as per instructions.

Finally, if you only do a low mileage and are not a flat out rider in a hot country, forget the synthetic.

Good Luck

Charles, yesterday someone told me that if synthetic oil is run at 80 deg C then its service life is halved. Do you agree?

David

I've got straight 40 in mine.

Whoever told you that running synthetic oils at 80 deg. C. reduces service life by any amount is misinformed. These oils and modern mineral based oils are tested at full power and 150 deg. C for 3 days and then visc. change is measured and must meet stringent limits. 80 deg. C. is actually a rather benign temperature from the oils point of view.

Synthetic oils stand up to extreme service conditions better than mineral ones, but few of us need to use them.

Previously charles_bovington wrote:

Whoever told you that running synthetic oils at 80 deg. C. reduces service life by any amount is misinformed. These oils and modern mineral based oils are tested at full power and 150 deg. C for 3 days and then visc. change is measured and must meet stringent limits. 80 deg. C. is actually a rather benign temperature from the oils point of view.

Synthetic oils stand up to extreme service conditions better than mineral ones, but few of us need to use them.

Thank you, that's reassuring as I have a Trident without oil cooler but with a temp sensor and during road use it easily reaches about 70 deg and on track it can exceed 80 deg. I also run my Commando on fully synthetic and although I don't race it I just feel that the extra bit of money for fully synthetic is justified if it reduces the wear rate.

Previously william_brown wrote:

Hello All,

Having asked the question about friction eliminators. What is the general concensus on engine oils. Mineral or Synthetic ?

Having looked through the box of bits that accompanied my 68 commando (age is correct this post) which i have owned for less than a month now. I discovered a label for Silkolene Castorene Classic R40 and the bike has a sweet smell to it.

Oil technology has obviously moved on but is it stillbest to stick with what the manual states.

Cheers

Billy

Hi Billy,

I've been running my 750 Commando on Castrol GP 50 with no problems, and to get that classic smell of R40 add a wee bit(100ml) into the petrol during fill ups.

Mac.

Hi Billy

What Charles correcty mentions, but others fail to stress, is that if your Commando does indeed have Silkolene Castorene R40 in it then this is a type of vegetable based castor oil and you MUST NOT try to add, or replace with, a mineral oil (whether refined or part or fully synthetic).

It is unusual to find a Command running vegetable oil; usualy it is for OHC machines where the oil allegedly raises the rider's sense of arousal

If it is a vegetable oil then it will very reluctantly dissolve in petrol, but will dissolve rapidly in methanol.

The quoted rule for switching between vegetable and mineral is to wash the whole engine. Others think that if you drain, remove and wash the oil tank, run on a hight detergent flushing oil until warm, and then replace with the chosen oil, all will be OK. I dare not recommend.

The Commando is a 'sloppy fit' engine and modern synthetics were designed for closer tollerences; but of coure they will still work. But, most importantly, only the older 'classic' oils contain zinc dialkyldithiophosphatethat many consider essential for higly loaded parts like camshafts and tappets wiping on valve stems. There are many views out there in internet land but this is one (American) example:

http://blog.hemmings.com/index.php/2012/10/18/tech-101-zinc-in-oil-and-its-effects-on-older-engines/

It is not true that only classic oils contain zinc di thio di alkyl di phosphates.

I have no idea where this misguided information comes from. Modern oils also use ZDDP's and offer better cam/ follower wear protection than do their predecessors.

I respect your knowledge of lubricants and so your comments are most helpful. Some other comment that I have read over the years comes to mind: Do all 'modern' oils (i.e. fully synthetic) contain ZDDPs? Is it true that ZDDP levels have been reduced/eliminated to avoid poisoning catalysts? Why are maintained ZDDP oils so popular in particular niche applications?

Are you of the view that higher levels of ZDDPs is old technology and now superseded?

This is a debate which will go on and on - and has been for longer than I care to think. I can remember as an engineering student back in 1970 being in a discussion on which oil is best for our Nortons which was halted by an old gentleman who stated - "If you were stuck you would be happy to use melted butter". Going further back, in 1930, my father used steam locomotive superheater oil in his 680cc Zenith and 30 miles later the big ends failed. So that's one oil to avoid.

Previously norman_lorton wrote:

I respect your knowledge of lubricants and so your comments are most helpful. Some other comment that I have read over the years comes to mind: Do all 'modern' oils (i.e. fully synthetic) contain ZDDPs? Is it true that ZDDP levels have been reduced/eliminated to avoid poisoning catalysts? Why are maintained ZDDP oils so popular in particular niche applications?

Are you of the view that higher levels of ZDDPs is old technology and now superseded?

Crankcase oils, ancient or modern,synthetic, semi synthetic or mineral based all contain ZDDP's. There are a wide range of different ZDDP's available to the oil formulator, they have different alkyl groups, different anti-wear properties and different anti-oxidant potency and costs.

Initiaaly developed as anti-oxidants in the 1930's, they decompose peroxides formed by base oil oxidation. These peroxides are one of the pathways by which polymerisation of base oil to form varnish, gums and deposits forming. ZDDP's also form elastic, glassy films at high contact pressure slidding contacts such as occur at cam/follower contacts and between piston rings and cylinder liners at top ring reversal.

SOME modern oils meet specifications which require lower levels of Sulphur and Phosphorous in the oil as these are percieved as being bad for catalytic converters. In Europe ACEA, who set general oil specifications, has a seperate catagory for these oils, ACEA C. ACEA A and B catagories have no such restrictions.

ACEA C catagory oils must have the same wear protection properties as the A and C catagoies. Some formulators may use Boron based anti-wear additives to ensure this, others do not need to.

For each ZDDP there is an optimum concentration above and below which wear is accelerated. For most ZDDP based formulations the reduction has little or no efffect. The Classic market is a nice little earner, I trust, I do wonder at the primary source all of the misinformation flying about.

Charles - lots of interesting technical stuff - but although you seem to criticise the 'Classic Oils' you don't actually tell us what oil you use or recommend in an air cooled twin. Modern oils are all much lower viscosity than I understand to be ideal for roller bearing air cooled M/C engines. I'm using Halfords Classic 20/50 in my twin (Dommie) and Morris 40 or 50 in a 16H. Should I use synthetic 10/40 so as to keep up to date? Do I really need effectively 10 grade when cold? The 16H would probably cost more to run in oil than it does in petrol!

Also how hot do our oils become compared with modern car engines? If a 15-40 in an old bike is not as hot at working temperature as expected by the maker then it will be less viscous than a straight 40 at the same temperature. And motors with old fashioned large clearances need more viscous oils.

Some of the replies, on this thread, are getting far too technical. Why use a "Hi-tech" oil in a low tech motor? Halfords Classic 20/50, as mentioned by David Cooper, should be quite suitible for most Nortons in normal use (singles & twins).

Modern car engines are quite different. My turbo diesel only requires an oil & filter change every 30,000 km (and does not need topping up between).

Previously David Cooper wrote:

Charles - lots of interesting technical stuff - but although you seem to criticize the 'Classic Oils' you don't actually tell us what oil you use or recommend in an air cooled twin. Modern oils are all much lower viscosity than I understand to be ideal for roller bearing air cooled M/C engines. I'm using Halfords Classic 20/50 in my twin (Dommie) and Morris 40 or 50 in a 16H. Should I use synthetic 10/40 so as to keep up to date? Do I really need effectively 10 grade when cold? The 16H would probably cost more to run in oil than it does in petrol!

Also how hot do our oils become compared with modern car engines? If a 15-40 in an old bike is not as hot at working temperature as expected by the maker then it will be less viscous than a straight 40 at the same temperature. And motors with old fashioned large clearances need more viscous oils.

The riding habits of Members vary greatly as do the bikes they own. Some ride long distances at Speeds which are just legal, others potter around country roads. Some are well worn, others are reconditioned to better than new standards.

Many modern motor car oils are of ultra-low viscosity to allow emissions targets to be met. It is ,I admit, getting harder to find suitable higher viscosity multigrade oils which have been tested to modern standards, but ,Mobil for one, market 15W50 oils which are ideal for serious users of Norton Twins. Opie oils web site and Halford give details.

With regard to 10W40, or any other multigrade, yes at low temperatures it is less viscous than a single 40 grade,but this is no bad thing. Viscosity decreases with increasing temperature. Thus a 10W40 oil will still be more viscous at 40 deg. C. than a straight 40 grade will be at say 100 deg. C. The straight oil at low temperature will dump most of the pump output into the timing chest while the 10W40 will pump it to the bearings. Which do you prefer?

My concerns about classic oils were published in Roadholder 285, they can be summarized as follows, Poor detergency + dirty pistons, poor dispersancy + sludge problems and increased wear. No certainty of quality beyond the say so of supplier as specifications are either non existent, most single grades, or in the case of multi grades, obsolete and untestable.

The downside of multi grades is more wet slumping. Hey Ho problems are always with us.

For the record, My 99 runs on a well known 15W40 all mineral oil, but since it is faster than I am , it doesn't need Mobil 1.

Since all the major oil companies buy their additive packages from the company who now pay my pension, I can't recommend one over the other.

If you have a low power high oil consumer, then a straight, cheap oil is economically sensible, as might be a rebore.

Modern oils are not expensive, only if you buy the branded names. I use a supermarket fully synthetic who also sells Mobil 1 beside it, so guess which company they are in bed with! The stuff I use is cheaper than the 'Classic Oils' that are well advertised, but I remeber the ads in my magazine collection selling Mulitgrade in 1957 - way before the Commando, so believe that there may be some market hype going on.

As to regards the huge clearances in our old engines needing a classic oil, surface protection is what really matters, how this achieved these days most probably overcomes the issue with clearance. Having used the modern technology oils and greases in my last job as an armourer, the jump in technology is huge.

An american gun was prepped and buried in sand for 30 days, removed, shaken to remove the sand and had to pass the test buy firing 30,000 rounds - it passed, the firing rate was 3,000rpm in burst fire. The wear on inspection was minmal and below what was predicted. The grease, water based, non-toxic, non-flammable, is not authorised for public use in the UK due to refusal of disclosure of contents, but can be obtained from the US.

As an engineer, I trust the advance in oil technology!

An AK47 was recovered from the Suez Canalcompletely encrusted in coral-like crud. After hours of painstaking chipping the crud off, it was taken to a range and fired successfully. Said AK47 is now in the hands of the Scottish Police. Nothing to do with modern grease, merely good materials and robust construction. Just like out old Nortons! Pause to recover from sudden coughing fit.

Previously norman_lorton wrote:

I respect your knowledge of lubricants and so your comments are most helpful. Some other comment that I have read over the years comes to mind: Do all 'modern' oils (i.e. fully synthetic) contain ZDDPs? Is it true that ZDDP levels have been reduced/eliminated to avoid poisoning catalysts? Why are maintained ZDDP oils so popular in particular niche applications?

Are you of the view that higher levels of ZDDPs is old technology and now superseded?

Crankcase oils, ancient or modern,synthetic, semi synthetic or mineral based all contain ZDDP's. There are a wide range of different ZDDP's available to the oil formulator, they have different alkyl groups, different anti-wear properties and different anti-oxidant potency and costs.

Initiaaly developed as anti-oxidants in the 1930's, they decompose peroxides formed by base oil oxidation. These peroxides are one of the pathways by which polymerisation of base oil to form varnish, gums and deposits forming. ZDDP's also form elastic, glassy films at high contact pressure slidding contacts such as occur at cam/follower contacts and between piston rings and cylinder liners at top ring reversal.

SOME modern oils meet specifications which require lower levels of Sulphur and Phosphorous in the oil as these are percieved as being bad for catalytic converters. In Europe ACEA, who set general oil specifications, has a seperate catagory for these oils, ACEA C. ACEA A and B catagories have no such restrictions.

ACEA C catagory oils must have the same wear protection properties as the A and C catagoies. Some formulators may use Boron based anti-wear additives to ensure this, others do not need to.

For each ZDDP there is an optimum concentration above and below which wear is accelerated. For most ZDDP based formulations the reduction has little or no efffect. The Classic market is a nice little earner, I trust, I do wonder at the primary source all of the misinformation flying about.

well I agree with Charles on this one Synthetic oils are a lot better now than ever oil technology moved on from your straight w40 or w50 even Castrol R . racing oils have moved on to what so good back in the 1950 or 60 was the technology then , now its a lot better oil than ever so then you pay your money and take your choice if your engine goes bang you know you got the wrong oil , yours anna j

Lubrication failure is only one of many causes of an engine going bang. As an aside, from time to time I ride a very original 1913 Douglas which has never been near modern synthetic oil. If something can last 100 years on low-tech oil, there's not a huge amount wrong with old fashioned oils. As long as there is plenty of clean oil going round an engine, you aren't going to get too many problems. It could be that modern synthetics reduce wear, but I don't think many of us put seriously high annual mileages on ourNortons these days to find out. Even before synthetics, you would get impressively large mileages between rebores or bottom end rebuilds.