Hi Guys. please will somebody tell me what engine, gearbox, & chaincase oil should use in a M20. Thanks.

email (option): pat.slinn@btinternet.com

Pat,

According to BSA manuals SAE 50 in the summer and SAE 30 in the winter. SAE 40 might be a good average for the whole year.

Best regards,
Leon

email (option): leonhop3@planet.nl

Hi Pat...I use Morris's SAE40 with a change to a 50 weight for the engine and box if we have a hot Summer ( )..I haven't had to use a 50 for quite a while ...Ian

email (option): ian@wright52.plus.com

I just use what's lying around on these old things. Molasses, Treacle, sump oil!!

As I understand the situation:
Some years ago, environmental science apparently discovered that the oil additive ZDDP (Zinc Dialkyl-Dithio-Phosphate), when burned in even minute quantities, was damaging the catalytic converters on gazzillions of cars and therefore not a good thing for our planet, so had to go.
The purpose of ZDDP was anti scuff, to provide long life of flat tappets and camshafts. Reasonably recent engines run without ZDDP exhibit rapid wear of camshafts and flat tappets, but roller follower engines apparently show no effect.

The removal of ZDDP from most engine oils was permitted to be delayed until most current vehicle manufacturers switched to roller cam followers, in one form or another.

Since then, in many instances, the oil companies have changed their oil specs by removing, or drastically reducing the ZDDP from many known and trusted "Brand Name" oils, but retained the original product name.(How many people read the fine print on their oil containers?).
So, the XYZ oil which you have used for decades, may now in fact be a completely different product.

Oils with enough ZDDP additive are still made and sold by most major oil companies, but with few exceptions the oil companies do not actively promote them, you have to be a conscientious consumer and seek them out yourself.
Some oils intended for diesels contain enough ZDDP for flat tappets, some don't.

Due to their excellent metallurgy and quality control, M20 BSAs with all original BSA parts fitted, may not suffer from follower and cam wear due to lack of ZDDP, but how do you know the suitability of modern replacement parts, and the origin of the parts in your 60 year old motorcycle?

Nowadays, to be safe, you should ensure that your engine oil is suitable for flat tappet engines, if you don't, you may just kiss your cams and cam followers goodbye.

However there is no guarantee that oils containing enough ZDDP will be available forever.

Those who own older vehicles are after all only a minority group, who's disadvantage "in the big picture" can be regarded as collateral damage.

As usual there is a lot of mis-information and BS on the net.

You can start to sort out the facts here,

http://en.wikipedia.org/wiki/Zinc_dithiophosphate

As the old Castrol ads used to say, "oils ain't oils"!
And now there is another new game in town.

First, do no harm.

email (option): n.gentner@bigpond.com

Thats very interesting Neale, Looks like we need to track down who (brand) and and what names or grades Used within the brands contain enough ZDDP for our old engines But how Much ZDDP is Enough I like others will checkout the oil we use, I personally use Morris oils (I live in the UK) and post them on this forum Andrew,h,

email (option): warbikes@gmail.com

ZDDP has been in use for over 70 years, so was introduced around the time when our bikes were built..It seems to be considered a desirable additive to engine oils as an anti wear and anti corrosion enhancer..
There are after market products that contain ZDDP that can be added to engine oils to provide the required additional protection. However, too much ZDDP can also be harmful apparently, so care must be taken in the use of any additives...Also, of course, you need to know what is in the oil in the first place!...If your oil of choice still has it is it necessary or even sensible to add more?...
I have emailed Morris Lubricants with an enquiry asking for some clarification with regard to their product...I'll post the results of that when I get them....Ian

email (option): ian@wright52.plus.com

There are a plethora of suppliers of ZDDP additives 2 come to mind Eastwoods who I believe have retailers in UK and Liquid Inteligence In AUS. Whist there a health risks attached to this product. There is a point of view that the principal reason for the removal from lubricating is its role in the creation of Phosphates in the exhaust an consequential reduction in Catalytic converter life and efficiency Valvoline evidently still produce oils stil containing ZDPP.

Ron

email (option): Grumpy.moran@gmail.com

I've had a reply from Morris's...Removal of ZDDP has not been legislated for (at least in the UK), rather it is an alteration made in tandem with developments in car engines, catalytic converters and oil itself. Modern synthetic oils as produced by Morris's and others have alternative, improved, anti wear additives that don't damage catalytic converters, along with other substantially changed specifications. Consequently, this makes them unsuitable for the wider tolerances and differing operating conditions found in older engines..
Their range of oils specifically manufactured for older engine types still have the same amount of ZDDP that they have always had and there are no plans currently to radically alter the specification....So, I guess you should find a Morris's supplier or check out the specs of any oil you are planning to use with the manufacturer....Ian

email (option): ian@wright52.plus.com

Every body stop & think for a minute or two.
How many hours are you going to be running your M20 for per year ?
How musch exterme pressure does the valve springs put on the cam followers ?
All what has been said is true but none of it is really worth worrying about unless you plan on doing 3 world trips this season.

FWIW I have been using Western Oil 20 W 50 in my M 20, B 40 A 65, A 10 L300's ( Gas & Petrol ) RR Silver Shadows & Perkings deisel fork lift for at least 4 years and befoer that it waas Valvoling 20 W 50 in every thing.
All seem quite happy running on it
Even the cheapest supermarket home brand oil would be of a better quality that what they were run on in their day.

email (option): wariron@tpg.com.au

Now to answer the actual question.
Engine oil see previous posts.
Gearbox oil, almost any oil that is listed as "syncro safe" others contain too much sulfur which attacks the bronze bushes.Thick oil will make changes slooooow thin oil will make the changes fast & noisy.
Clutch.
I favour ATF simply because it is pinck which allows you to quickly pick an oil leak source.

email (option): wariron@tpg.com.au

Most modern engines run on synthetic oil in a light grade..10/40 for example..and a 20/50 is already 'behind the times' to a degree...
Whatever oil is being used though, surely it is not possible to make any observations about its effectiveness or otherwise in relation to the topic under discussion unless a)it is known whether the additive is present or not and b)in what quantities it is present relative to the theoretical optimum.
Then a back to back test in one engine under controlled circumstances with varying amounts of the additive would be needed to draw any definitive conclusions. That isn't really practical for most of us so all we can do is look at the available facts and consult those more knowledgeable on the subject...
This additive was conceived in 1941 and has been added to engine oils in one form or another ever since because of its proven effectiveness as a wear inhibitor.
This has only changed recently and largely because of its incompatibility with catalytic converters. So it is likely that if you are not buying a synthetic 10/40 specifically for a newer vehicle it is more than likely it is in the oil you are buying to one degree or another..Even the environmental evangelists in California haven't banned it totally, yet.
However, it would seem to be sensible to determine that it is present in whatever oil is being used....Just as sensible in fact as establishing it is not in the oil you put in your late model car...
There is no need for hysteria, only the reasonable determination to identify the most suitable product to use, and there is nothing to be gained in being cavalier about the subject either...In fact the idea of deliberately using a less suitable oil than you could seems a little odd....
A question about this additive has been raised and personally I don't see a problem with finding out the information that is needed and making a best judgement based on that...Ian

email (option): ian@wright52.plus.com

As Ian found with Morris's, I guess that most oil companies supplying monograde oils, ie the type our engines use (straight 50 in my case) wont change anything as modern cars with catalytic converters don't run monograde. So I wouldn't worry. But my car might suddenly get noisy in a few years!

It was discussed here in the past.
Some were in favor of mineral cheap oils, as the engine can do 80K miles with them,
And some said that they would invest in more expensive synthetic oils, in order to make the engine last longer,
But if there is no ZDPP in the synthetic oils, then it is better for the engine, but bad for the cam system, unless ZDPP is added,
If I understand correctly…

Noam.

email (option): noam10@gmail.com

Morris's Technical dept. said that the modern synthetic oils still have wear inhibitors..just not ZDDP. In fact they said they are better wear inhibitors...The problem with these synthetics is that the rest of the specifications of the oil make them unsuitable for older engines...Ian

email (option): ian@wright52.plus.com

synthetic oils are to thin for old engines especialy with the large tolerances ie air cooled engines they will burn lots of oil and it hard to keep a good oil pressure

email (option): roger.beck@node6.com

That's not the case Roger, I use Rock Oil TRM. It's classed as a 20/60
Here's the spec;

Rock Oil TRM 20/60 is the ultimate lubricant for all highly stressed 4 stroke engines.
TRM fully synthetic 20w60 is a specially formulated synthetic oil containing selected large molecule base fluids combined with a unique additive package.
TRM is especially good for engines with roller bearing crank shafts and V twin engines used under arduous or racing conditions.
TRM is equally suitable for both roller and plain bearing crank shafts and can be used for air or liquid cooled applications and is also a superb gear lubricant and is ideal for unit construction engines. It is suitable for all modern high performance applications.

Oil type:
Fully synthetic 4 stroke

Viscosity rating:
20w60

email (option): horror@blueyonder.co.uk

This is very unusual, Horror..

Seems like a great viscosity for old engines, and 20W-60?...
All of the full synthetic oils I know, usually starts with 5 / 10 or 15W..

By the way, I was always using a monograde 40SF oil,
And last time I could not find one, and used a 20W-50,
But as the BSA oil runs so cold
(I do not think it even reaches more than 50 deg cel’/ 120 degrees F’)
Even with the very good circulation I have, and even in a hot summer,
I am not sure what viscosity it reaches, meaning- does it get to “40” or “50” grade at those temps,
Or does it take, say 70-80 deg’ C (About 170F) to get there?
Never seen a Heat-to-viscosity graph of a typical 20W-50 mineral oil..

Noam.

email (option): noam10@gmail.com