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3 hours ago, JochemsTR said:

this links shows the 20W50 with an even higher Zinc content.

I think if owners want the high zinc content it would be wise to check to see what is supplied. If it’s for the European market it won’t be the higher zinc, check the bottle if anything is printed there, and if not made in the US or Canada it won’t have the zinc. Maybe what you’ve bought has been imported and then will have the zinc.

Mick Richards

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On 10/7/2020 at 8:50 PM, SpitFireSIX said:

 

Continue litmus go on.

Wasn’t he in the Peanuts comic strip. ?

:ph34r:

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1 hour ago, Hamish said:

Wasn’t he in the Peanuts comic strip. ?

:ph34r:

Nah! That was Linus.:ph34r:

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On 10/8/2020 at 3:34 PM, JochemsTR said:

...and since it is on the internet...it must be true

I have always loved Dutch sense of humour :D

(BTW Jochem - if you're not Dutch, I mean no disrespect. Your humour is still priceless...)

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6 hours ago, JohnC said:

I have always loved Dutch sense of humour :D

(BTW Jochem - if you're not Dutch, I mean no disrespect. Your humour is still priceless...)

Thank you John....yes I am Dutch....living in Germany....so you can imagine my humour being appreciated here.

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Please see a reply I received from a Duckhams oil technical specialist who has answered a few questions regarding the properties of synthetic v mineral oil, notably zinc content which was discussed in particular, the hazards of using additives and the correct applications for mineral and synthetic oils......

 

“ Further to your email enquiry of 7th October.

·         Does modern fully or semi-synthetic oil have a zinc content and if so to what level (ppm or percentage)

Most engine oils rely on anti-wear additives dissolved into the oil which protect the engine again wear.  These additive are normally based on Zinc Dialkyl Dithiophosphate (ZDDP) compounds, which contain both Zinc and Phosphorus in the molecules.

Unfortunately, it has been found that the Phosphorus within the anti-wear molecule can poison three-way catalytic converters.  Also, the presence of metal atoms within the lubricant can lead to the formation of ash in the exhaust gases which, over time, can block particulate filters.

To address these concerns and reduce the emissions of engines, the amount of Zinc and Phosphorus which can be added to the lubricant has been reduced over time, and Engine oils have been designed to offer higher protection with reduced metal amounts.

The changing specifications have reduced the amount of Zinc found in modern engines to typically less than 1,000 parts per million (ppm) of Zinc (0.10% Zinc).  Some specifications, such as the latest ACEA C4 can be achieved with as little as 500ppm (0.05%) Zinc.

The amount of Zinc present in modern oils vary significantly depending upon the specifications the oil is designed to meet, however, they normally fall in the range of 500 – 1,000ppm (0.05% - 0.10%).

·         Does synthetic oil damage or have adverse effects on rubber seals, bearings and camshaft components in older engines

Synthetic oils are oils that are either very highly refined oils or are manufactured using chemical reactions to build molecules of the appropriate length for the required viscosity (thickness).  As part of this process, the chemical weaknesses which exist in normal mineral oils are removed.  This gives synthetic oils much better thermal stability, meaning that they will last much longer before they start to degrade.  This gives the oils a much longer life.  The downside of this is that weaknesses in mineral oils which cause their degradation, also give mineral oils better solvency.  This means that if an engine has been run on mineral oils for a long time, the oil will have permeated into the rubber used in the seals, causing them to swell slightly and ensuring a good seal.  If an engine which has been run on mineral oils is switched to a synthetic oil, there is a risk that the oil in the seals may be absorbed into the synthetic oil, leading to the seals to shrink (and possibly harden) which in turn can lead to oil leaks.

Using synthetic oils in ay engine fitted with new seals will cause no issues at all.

Oils type will not affect metallic components within the engine at all, they will be much more affected by the viscosity of the oil, or the additives used to blend the oil.

·         Does Duckhams 20W/50 mineral oil have the same zinc content that it did in the 1960’s and do you have a data sheet for this

I have attached the Product Data Sheet for ourDuckhams Classic Q 20W-50.  As per the datasheet, our product contains 0.11% Zinc as ZDDP.  This is the same treat rate as was used historically to manufacture Duckhams Q 20W-50.

·         What are the primary differences between mineral oil and fully synthetic oil  which might make it unsuitable for older engines

The major differences between Mineral oils and Synthetic oils are the solvency and thermal stability, as mentioned above, and the viscosity.  It is easier to achieve higher viscosity (thicker) oils when using mineral oils than it is using synthetic oils.  This is due to the refining process shortening the length of the molecules within the oil, which makes them less viscous (thinner).  This is a benefit in modern vehicles where new manufacturing methods allowed for tighter operating tolerances which can be successfully lubricated using thin oils.  This also reduces the internal friction within the engine and therefore increases the efficiency of the engine.

However, in older vehicles, where the clearances are greater, thin oils will not offer sufficient oil film strength to maintain lubrication, and so would lead to engine wear and increased oil consumption.  This is why it is essential to ensure that you always use the correct viscosity grade as recommended by the vehicle manufacturer.

·         Can synthetic oil be used in conjunction with an oil additive in a classic car engines

Blending Engine lubricants is a complex science to balance the conflicting demands of protecting the engine without causing corrosion, such as rust.  Engine oils are finely balanced mixtures, and so we would not recommend using oil additives with any type of engine oil, with the possible exception of an engine flush additive which is used for a very short period of time before draining the oil from the engine.

·         What is the best way to express ZDDP content, as a percentage or ppm

When measuring the Zinc content of an oil we are directly measuring the amount of Zinc, not the amount of ZDDP.  As explained in the answer to your first question, ZDDP is a molecule that contains Zinc.  However, it is possible for a lubricant to have other Zinc containing compounds as well as ZDDP.  To ensure you are looking at the right figure you want to see Zinc (as ZDDP), as shown on the Product Data Sheet for Duckhams Classic Q 20W-50.  It is not important whether it is reported in percent or parts per million (to convert between the two you merely need to divide or multiply by 10,000).  As a general guide, ZDDP content will be approximately eleven times the Zinc (as ZDDP) content.

 

I hope this provides clear answers to the questions you have raised and reassures you that Duckhams Classic Q 20W-50 is the best appropriate oil for Classic Cars requiring a 20W-50 oil.

 

Best Regards

 

D Ian Atha 
Technical Manager 

 

Alexander Duckham & Co., Ltd 
1 Merchants Place,  
River Street, 
Bolton, England, United Kingdom, BL2 1BX “

Edited by boxofbits
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Boxobits,  That's a very clear response from Duckhams re Classic Q20W/50.  1100 ppm Zn as ZDDP looks fine to me , now.  Peter

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As I recall a lot of the leaks concerns (other than as a result of being too thin) came from the early days of Mobil 1 - one of the firrst widely used synthetic oils in the UK. Apparently the additive package in the early days inadvertantly omited the one that helps maintain the seal / seal swell and leaks appeared.

I believe most good oils - mineral or synthetic contain swell additives these days.

As the Duckhams chap says - many modern oils are formulated for modern cars with cats and zinc as packs are not good for cats. Our concern is that the alternatives are not necessarily so effective in protecting the cams and followers of older cars like ours as they are in protecting modern cars with overhead cams and lubrication systems.

modern engines are designed with tight tolerances that allow thinner oils to be used with adequate levels of protection and reduced drag. The same thin oil may not be be so effective in our cars with looser tolerances.

The basic concept of synthetic oil is good but it has to of the right viscousity for our cars and offer the same cam protection.

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Modern high-detergency petrols my not be so good. The late Oldtuckunder always ran his 6 pot on VR1 oil (high in ZDDP) and a high detergent fuel. All six evs were covered in a white deposit, possibly zinc oxide. No certainty about this but it may be the fuel stripping ZDDP off the rings and bores....

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Hello,
My experiences in driven KM have shown that synthetic oils provide the best lubricant.
In my case, Castrol 10/60.
Please compare the HTHS value and the viscosity index with other oils.
The HTHS value is a decisive parameter against wear
In the TR 6 I have now driven about 240,000 km with 10/60! 110000/13000 km
During the year I also drive many kilometers on the racetrack. I demand a lot from the machine.
The valve clearance is constant and the machine is perfectly clean.
One thing you have to be aware of, however, is that if the valve springs are installed too hard, even a very good oil will not help.
Example my Spitfire 1500.
Bought new in 1981, at 92,000 km, camshaft dead.
I also use 10/60 motorsport oil in other vehicles, of course without the approval of the manufacturer (Mercedes Benz)
Oil consumption is not an issue.
Oil change before 10000 km is a matter of course.

regards
Ralf

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This is all very interesting stuff on viscosity and tolerances in engines etc  but one of the problems with TR's in general is that they don't get used on a regular day to day basis.  Taking two of my own cars for example,  the Dove rarely does a couple of runs per month, usually at a weekend, but when I do take it out it usually clocks up a few hundred miles each time. However, my TR3S  race car hasn't turned a wheel for over a year now and while the tolerances on its engine are much finer than a standard TR, its the ability of the oil to NOT drain away from the cylinders and other moving parts that is important as you need to keep a thin film of oil on all the affected surfaces too inhibit rust developing inside the engine.  For that reason I use an oil which has an additive called PARATAC which is used to provide 'tackiness' to the oil  which helps it cling to the moving parts of an engine and thus reduce wear on start up.   As far as I'm aware not all so called 'classic oils' use this additive and so it would be interesting know if Duckhams, Castrol or some of the other oils which are mentioned here and on the market use it in their blends. 

hogie 

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Paul -I shouldn't have to tell you there is an easier solution than additives - drive the car!

On a more serious note I suspect that a great number of our cars will have done far less mileage than in normal years and next year, if things improve, will see more breakdowns as a consequence of not being used, with oil draining away and bearings, UJs and bushes running dry because they haven't had the regular use.

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8 hours ago, Paul Hogan said:

This is all very interesting stuff on viscosity and tolerances in engines etc  but one of the problems with TR's in general is that they don't get used on a regular day to day basis.  Taking two of my own cars for example,  the Dove rarely does a couple of runs per month, usually at a weekend, but when I do take it out it usually clocks up a few hundred miles each time. However, my TR3S  race car hasn't turned a wheel for over a year now and while the tolerances on its engine are much finer than a standard TR, its the ability of the oil to NOT drain away from the cylinders and other moving parts that is important as you need to keep a thin film of oil on all the affected surfaces too inhibit rust developing inside the engine.  For that reason I use an oil which has an additive called PARATAC which is used to provide 'tackiness' to the oil  which helps it cling to the moving parts of an engine and thus reduce wear on start up.   As far as I'm aware not all so called 'classic oils' use this additive and so it would be interesting know if Duckhams, Castrol or some of the other oils which are mentioned here and on the market use it in their blends. 

hogie 

It ran fine on Halfords classic 20/50 ;)

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