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Many manufacturers are rather coy about the actual amount of Zinc (as ZDDP) their product contains.
As mentioned in the past, Classic Oils have it clearly stated on their Heritage Mineral 20/50 packaging and available at a fair price.

…….  Andy

Edited by AndyR100
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A few years ago I wrote to a few of the manufacturers enquiring about the ZDDP content of their 20w50 classic oils. (Wrote an article for the Leicester group newsletter TRipe)

Most were quite happy to disclose the levels. Morris weren’t willing to disclose, and gave a waffly response about how it wasn’t just about ZDDP and were rather patronising. My interpretation was that meant little or none and thus not really suitable for our cars.

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11 hours ago, Ralph Whitaker said:

OK, I thought I had this "what oil" question sorted, until I read the above posts concerning ZDDP.

I have been using, and indeed have a stock of, Morris Golden Film 20/50, used by others with TRs, and have been happy so far. 70psi from cold and at all speeds above 2000rpm, drops only to 30 psi when hot on tick over.

Reading about the ZDDP I thought I would check, and there is no mention of it on the Morris website, in the data sheets, or on the back of the container. There is the worrying statement that " it can also be used in modern, high mileage, vehicles where oil consumption may be a problem"   If that is the case then it must guarantee that there is no ZDDP, as previuosly stated that would be death to catalytic converters.

I also read that it is a low dispersant oil allowing particles to drop to the bottom of the sump. That might be fine for some vehicles with by-pass filters ( early TR2s ?), but I have a full flow filter with a spin on conversion, which makes me think I need a high detergent oil. My engine has only done 3000 miles since being re built, so there should not be vast quantities of sludge around yet.

I have a 5 litre can of Millers Pistoneze 20/50 which I have not used yet, and looking at the blurb for that reads as below,

 

DESCRIPTION:

A moderate detergent premium SAE 20w50 multigrade mineral engine oil specifically engineered for classic cars incorporating a modern filtration systems. Contains high quality solvent refined base oils with latest technology performance additives and shear stable viscosity index improver. Formulated with ZDDP (zinc/phosphorus).

APPLICATION:

Use as received for engine lubrication of primarily pre-1980 vehicles, both petrol and diesel, which were developed on the multigrade oils of their time.

 

So I am thinking this seems to meet the requirements better, being "moderate detergent", for "modern filtration systems" and "Formulated with ZDDP"

I can feel an oil change coming on.

Ralph

That would be fine to use Ralph. That is what I used to use until the price was not competitive with Classic oils Heritage 20/50.

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  • 2 weeks later...

If your engine is is in a good state of repair a 10w/;40 should be perfectly acceptable, 10w/40's have the benifits of being able to circulate around the engine quicker than a 20w/50 due to the lower viscosity at ambient temperatures, which help prevent premature camshaft wear. A 10w/40  will also have less drag at lower temperatures while still maintaining viscosity and protecting the engines at higher temp. An engine oil with higher Viscosity Index (V.I.) will have a better inherent viscosity range but will affect the cost.

The performance of an Engine  Oil is dependant on the quality of Base Oil and the additive packs used . I know from my years in BP/Castrol that the base oils they use  are robust and are selected on the basis of high performance .

The additive pack is where all oils differ regardless of application . An oil formulated for a petrol engine will have good detergency and dispersantcy performance but not as much as a diesel engine, simply because a diesel engine produces more insolubles. The formulations are balanced to provide the right level of anti-wear and anti-scuff performance without causing bore glazing. Cheaper oils may not hold the insolubles in solution for as long, leading to crankcase "painting" and the if the dispersant performance is poor the oil can gel .

When an engine oil is changed it should be darker and  thicker which indicates its cleaning the internals and allowing the filter to removed the particulates. The oil viscosity will also increase if used for too long, essentially the oil oxidizes as well as holding  the insolubles. the filter cant remove.

  . The additives in the oil will  deplete over time and use, to a point where the oil will become like  black treacle,  and can form  acids  (BN depletion). Re ZDDP additive its an adequate  anti-wear additive and also has some ant-oxidant properties  but does have drawbacks .With the introduction  of Catalytic converters the industry has been forced to move to alternative anti-wear additives  such  Octyl Acid Phosphate but there are  others .

What I would add is that Shell. Castrol, Mobil produce excellent engine oils .I have examined a number of  products which are not main branded oils and  many use preparatory additive packs which are not their technology and are formulated to a price   essentially they will meet a specification but not exceed 

I would add than adding  treatments to the oil may compromise element of its performance  but to be frank if they were of benefit the Main brands would  include them in their formulations

happy to answer any question via P.M.

regards

Steve

 

 

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