Engine oil

[Erich]

This was, as I recall, discussed at length(ad nauseam) on the old site, but I can't seem to get back to that thread. I know that many are running straight 30w. The question is, detergent or non detergent? The engine was built by Pigsty and it has been run on Halfords Classic 20/50 until now. The car will be coming to the US, and finding a non detergent oil will be an issue. It is splash fed with a spin on filter mod. The Chevron Delo 400 has phosphorus and zinc in low percentages. I had thought about running that in the gearbox also, but understand that phosphorus and detergents are bad in the gearbox. The phosphorus, I understand, will wear any bronze bushings.

Erich

[Martin Prior]

This was, as I recall, discussed at length(ad nauseam) on the old site, but I can't seem to get back to that thread. I know that many are running straight 30w. The question is, detergent or non detergent? The engine was built by Pigsty and it has been run on Halfords Classic 20/50 until now. The car will be coming to the US, and finding a non detergent oil will be an issue. It is splash fed with a spin on filter mod. The Chevron Delo 400 has phosphorus and zinc in low percentages. I had thought about running that in the gearbox also, but understand that phosphorus and detergents are bad in the gearbox. The phosphorus, I understand, will wear any bronze bushings.

Erich

Hi Erich.

As you say, ad nauseam!

I've run my Sevens for years on Morris's Golden Film Classic SAE 30 http://www.morrislubricantsonline.co.uk/...r-oil.html , which I buy 25 litres at a time.  Why not arrange to have a drum of this shipped with the car - it should keep you going for quite some time!

[Bob Culver]

Some o f the former more definitive posts cut through a lot of folklore and random notions but are now sadly difficult to find.
 
Relative the more traditional (now cheaper) multigrades, there is a somewhat theoretical case for monograde 30 in very highly stressed hot running engines. But scores of millions of vehicles including heavy transport , and with bearing loadings vastly greater than a Seven, used older style multi grades with low rates of wear undreamed of years before.
 
The argument for non detergent oil is
a)     it will be less inclined to release varnish flakes, compacted dirt,  and sludge blobs from a very dirty engine, with risk of blocked jets.
b)     in a clean engine without filter it may leave contaminants as large particles in the sump, hopefully not or seldom circulating, instead of as very fine circulating suspension. I dunno if anyone can find a paper establishing a wear advantage of the former, without filter or with; suspect in the realms of folk lore. Note  the late VW Beetle, without filter, and without forgiving white metal bearings ran detergent oils
 
A non detergent oil if also without all other modern anti wear, ant corrosion additives would be much as the API SB oils of the 1940s, with which Seven mains often rusted out with gusto, and cyls needed boring after 40,000. Not something to pay a boutique premium for.
 
The degree to which the antiwear additives in modern oils suffice, or whether the high ZDDP of earlier formulations, some of which are available in cheaper grades and in diesel oils, is superior, is beyond me. For many years Sevens had none. Loadings and rubbing speeds  in a stock engine are very modest.
 
As for gearboxes and diffs the debate is usually about EP oil and whether it damages bronze and polishes synchro cones. With many medium grade non EP gear oils and suitable engine oils cheaply and readily available,  gearboxes not an issue.  
 
The diff generates debate. Oil makers claim yellow metals not damaged by commonly available modern EP diff oils, but many prefer to use traditional  low EP gear oils, which in the heavy grades required to stem leaks and noise, require some effort to obtain. Later Austin publications for the Seven advocated EP oil; whether this less or more corrosive than present full EP oils, and whether or not significant, I dunno. My car, as thousands of others, ran EP for decades and the ball races did not collapse, nor the plain axle bearings vanish. 
 
My understanding is that EP corrosion was/is associated sulphur/chlorine EP compounds.  

Catalytic converters are allergic to phosphorus hence ZDDP etc phased out of petrol engine oil.

[Ruairidh Dunford]

Erich,

I happily use detergent oil if the engine has been thoroughly cleaned during full rebuild, if unknown I always use non detergent oil.

In my experience both straight 30 and 20/50 work equally well when following the above rule in both the engine and gearbox.

With reference to the rear axle, I avoid using EP oils that are labelled ‘Hypoid’ but have happily used EP oil labelled ‘Hipress’ over many years without issue. The original spec D140 also works perfectly in my experience.

My first port of call for any questions like this would be the engine (or axle) builder, their advice is key.

[Chris KC]

I've rarely seen so much sense in so few replies!  All I can really add is my own practical experience; I've run detergent 20/50 for decades on a pressure-fed, filtered engine without issues. And if I were running in a new engine of my own I'd make sure it was clean internally. I wouldn't contemplate a straight or non-detergent engine oil myself, though that's a fair point about 'unknown' engines. EP axle oil will turn gold, but will take a very long time to eat your axle. Keep in mind if storing oil that it does have a shelf life (though I concede I have enough Duckhams at home to see me out...)

[GK5268]

I re-built my engine a few months ago, and I have done about 300 miles or so since then, prior to this, the car returned to the road in 2015, and all I did in preparation for the engine was to thoroughly clean the internals, I didn't know how good or bad the engine was so ran it as it was for about 1,000 miles. When the bearing wear become too noisy to tolerate, i then did the re-build.

I had used a straight 30 SAE in those first 1,00 miles and I was shocked at the significant build-up of sludge in the sump and all over the crankcase walls, it was really dirty! All as if it had never been cleaned! Since the re-build, in order to assist with bedding in of new components I have used the same straight 30 SAE and I am about to do an oil change now the engine seems quite nicely run-in and this time I will put in a modern 20/50 (I use Comma) detergent oil, which should keep the internals much cleaner. The same oil I have used in my 1965 Rover P6 and I have done over 50,000 miles on a re-built engine and had cause to remove the sump a few weeks ago, the internals of that engine were still as clean as when first re-built, no sludge or nothing.

[Austin Carr]

The car will be coming to the US, and finding a non detergent oil will be an issue.

Erich

If you search "non detergent oil USA" you will find suppliers. There is a  supply problem California but this thread gives alternatives:-

http://www.practicalmachinist.com/vb/gen...ia-320958/

[Guy Butcher]

A thorny topic!
Choosing an oil is wisdom confounded by opinion?
Wisdom requires that you read Which Oil by Richard Michell pub Veloce. ISBN978-1845843-65-6.
Experience says that for a well built engine after the running in oil phase Morris 15w50 Golden Film Motor Sport oil for the engine with oil and filter changes at a max. 2,000 miles.
The gearbox usually uses engine oil and the back axle Morris Golden Film AG 140. This is essentially the schedule we used in the Bespk Austin and it seemed to work perfectly.
Finally if you should choose to use Morris Lubricants; they have an agent in the States; Robert Bauer; classicoilsupply@aol.com. He was simply remarkable at getting oil to us throughout our trip. www.bespk.com

[Ian Williams]

This topic comes up so often I wonder if it would be good to have a sticky thread or information page somewhere on the forum that covers the subject for new owners benefit?

[Bob Culver]

The book Which Oil is about the only easily readable text available. But the author seems to be an interested observer, not an up to the minute lubrication industry development engineer or chemist. He labours the sheer down tendency of multigrades, not now considered a major problem. But he does not mention at all the dynamic (fleeting) reduction  of viscosity under high shear, the curious and more contentious characteristic of traditional multigrades.
And the oil change periods recommended are incredibly frequent for engines with filters..
 
The book includes interesting graphs of viscosity of multi and mono grades at various temps (although care necessary with the scales).
 
I run a 1960s 1600cc Brit car. At 30,000 when I acquired it in 1987 it exhibited marked blow by. Medium quality oil has been used changed at 6,000- 8,000 miles. By 175,000 blow by was serious although little oil used; top rings found to be broken. Bore wear about .004 max. I wonder what it would have been with more frequent changes? Just how long are engines required to last?
 
Through the 70s and 80s I ran a Jowett Javelin. As is common, oil consumption was generous so for years I used a cheap re refined 30/40 oil which the makers claimed to have no additives. The engine internals were jet black with varnish; running was near ideal but bore wear seemed relatively rapid, although crank and cam wear, usually common problems, very low.
 
I suspect the main concern with Sevens is to avoid crankcase condensation potentially damaging to the roller bearings. Avoid brief starts. A thermostat might achieve more than very frequent oil changes