Hopefully that is enough time to break it in. Or at least the parts that can be broken in. I've found a lot of Chinese equipment, motorcycles, etc. where the valves are not properly seated, just cast and installed with no good seating face.

I just bought a one cylinder OHV-engined generator made in China. Came with jug of 10-30 regular oil .
Said if you are going to use synthetic to wait until  after 5 hrs running. 
FYI.

You do not need that much in break-in in general, and actually that much can slow your breakin process too much. The only extra needed is when you use a new cam, and that is provided by a smear of paste to the cam face-- and then only enough to coat a few microns, as that is all that really does anything. The rest washes away to mix with the oil and clog passages.

And you have no way of knowing how much you are increasing brand x oil with brand y additive to get a level of z.

A good diesel formulation will have 1300 to 1500, and is very sufficient for our engines. Get anywhere near the 1800 to 2000 ppm level and you will have cam galling according to SAE tests. Safer to just let the chemists at the oil companies make it.

....here it is the whole article for your reading pleasure. While opinions vary, I still think that old engines would not get along well with modern oils,
cheers,
Abel

I agree completely with this. There are a lot of veteran mechanics with antiquated ideas about how oil works. Remember that the 1st number describing a multi-viscosity oil is how it flows when cold. Is it vital for a Mini that it pour like a 20w straight grade oil cold? I don't think so. They may have come with somewhat looser tolerances from the factory than modern engines, but not that much looser.

The more primitive oils of the past needed to have the properties of a 50W oil to take the punishment of hot running. Modern (especially synthetic) oils are much more stable than vintage oils and can endure much tougher conditions.

The factory recommendations for the injection Minis (MPI at least) is indeed 10W-30. So Rover recognized that lubrication technologies had progressed by the late 90's.

It may also be interesting to note that the classic Jaguar XK engine (E-type), which is even older than the A-series, suggests 10W/30 oil as a suitable choice. It had this interesting note to that option:

"These oils should NOT be used in worn engines requiring overhaul. If an SAE 30 or 40 oil has been previously used in the engine, a slight increase in oil consumption may be noticed, but this will be compensated by the advantages gained."

So Jag didn't think 10W/30 was bad for its vintage engine, even back in the 60's with 60's oil tech!

sent via email Todd

Abel 
I would be grateful for a copy of this too. [email protected]

Thanks in advance.

The automotive user and mechanics have been used to the idea that thicker is better, a theory that has been proven wrong in the last 20 years or so. But the manuals gave two options. 10W-40 and 20W-50 (Someone reported in Canada their manual said 10W-30. If you are racing, the higher viscosity would be better as it will run at higher temps and therefore be thinner, more like the 40.

When you are talking about cams, it is the additive level of the oil that protects more than the viscosity. The oil film is basically not present under cam pressure at the peak.

In general, you want the oil to splash around, circulate, be able to squirt up to the pistons and around the valve train.

E-mail sent -

If 10-40 is so perfect, why did the factory specify 20-50, and why are the modern oil companies like Millers producing combined engine/gearbox specific oils that are 20-50 ?

Even the racing oils are 20-50, and Swiftune know a few things about racing an A-Series.

I've run 15-40 in the past, and the engine definitely cranked faster from cold but without tearing it down I don't yet know what the cam followers are like.

Yes, you need more than an SN oil, but no, you should not make your own with additives, as I doubt you are a chemist and have the equipment to analyze and blend to the right proportions.

The bottom line is that if you have a Mini with a manual transmission, you need to look for a Diesel formulation (CI-4 or CJ-4) of the right viscosity. If the engine is in good shape, that is 10W-40. You could use a synthetic 5W-40 CI-4 or CJ-4. If your engine or transmission is well worn, 20W-50 would be appropriate.

If your Mini has an automatic transmission (like mine), you want an oil that meets the JASO MA2 motorcycle spec. Again, 10W-40 would be the best viscosity, but 20W-50 if well worn. I use 10W-40 and have 170 psi at the filter head (before the pressure regulator/bypass). 

If you really want to know about it, click this link and you can read about 30 some pages. All you wanted to know about oil for flat tappet engines

...yes. it talks about all that and more.
Unfortunately, the scanned page cannot be zoomed. If you give me your email, I'll send you the article,
cheers,
Abel

well, since what you posted was only a teaser (no information so far on the subject), then my answer to your question is yes, please post the rest of it

I suspect it will say: zinc is important for flat tappet engines (like the A series), especially during cam break-in after a rebuild, and very few oils today provide enough for that. Hopefully it will include information about how many ppm used to be in oils, and what that amount has been reduced to due to today's pollution laws (if you google this topic you'll find may articles written by many sources have covered those two points). Then, it will probably say there is some dispute as to just how much is needed after break-in, but at least some amount is beneficial.

Then, hopefully, it will cite some real research on the subject. So far, most articles on this lack actual testing data to support just how many ppm actually must be in the oil used in an already broken-in, flat tappet engine. Without such testing data we are then left with conjecture and assumption as to what is necessary.

Without testing data, we are left with using one of the only two or 3 oils on the market which have 1200ppm, or simply running any 20W-50 oil and crossing our fingers.

Looking forward to learning what Hemming's writer has to say.

....following a very informative conversation with Doug K. Lawson, I read an interesting article on the September issue of Hemmings Sports & Exotic regarding old cars and the type of oil (and ZDDP additive) used/required). I am still a novice, so I am always eager to learn more about our cars,
cheers,
Abel

https://www.hemmings.com/magazine/hsx/2016/09/Oil--don-t-you-wish-you-knew-more-about-it-/3750062.html  This is just an extract, but I'll be glad to scan and share the whole article with those interested