Fast Marina Magazine

I remember asking this question a few years back and have trolled through old posts but can find it...so, what engine oil is everyone using? This question really goes to you that have tuned your cars as I am looking for a performance oil for mine but if everyone can answer as I'm sure it's useful information....

With all older engines you need to check the zinc content (parts per million, ppm). Where our engines use flat tappet cams it isn't worth the risk to pick an oil with less than 1000ppm. Try and pick one between 1000 and 1500ppm.

I've written a piece for the next magazine explaining all the other fundamentals such as viscosity, indices and the difference between minerals and synthetics so I won't repeat here just yet.

Go to https://www.classic-oils.net and have a look through the different brands. On each product they list the specs. I think you could do well with a Valvoline VR1 or Penrite oil. 15w40 or 20w50 depending on how many cold starts you do (W for winter).

If your engine has run on a mineral oil for over 30,000 I would stick to a mineral unless you fancy a 3 part conversion to fully synth. If the engine has done less miles it is easier to convert, but only with a classic formulation oil with the right zinc content.

If the engine has been freshly rebuilt I would stick to a mineral oil until it has "run-in", say around 1000-1500 miles then convert to synth oil.







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I was told to stick to a good quality mineral 20/50 when my engine was rebuilt to 1950cc spec. I use Millers classic.
http://www.millersoils.co.uk/automotive ... ne-oil.asp



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balmy wrote: Mon Mar 13, 2017 8:56 am I was told to stick to a good quality mineral 20/50 when my engine was rebuilt to 1950cc spec. I use Millers classic.
http://www.millersoils.co.uk/automotive ... ne-oil.asp



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If you are using the Pistoneeze, formally "Classic", or their "Sport" variety then I see no issues with a standard 1800 B series. Considering yours is a 1950 I would want a better flowing oil, give less friction and be sheer free. Synthetics such as a Penrite 10w40, 15w50 or even a 15w60 would offer better protection at both lower and higher temperatures as well as maintain viscosity over your service period. In either case, both the Millers and Penrite mineral and fully synth offer high Zinc content so you have the protection you need for the flat tappet camshaft, and also have a high detergent content so will keep everything clean and free of varnish deposits in your rebuilt motor.

Like everything it comes to personal choice. I wouldn't recommend a synth oil in an engine that had been to the moon and back, or that had run on mineral oil, and with very few changes throughout its life as they will harbour a lot of acids and other nasty deposits. But for an engine that is freshly built and has been run in on a quality petroleum based oil and has bearing tolerances either factory or tighter than factory specification I would go synth every time.

I will go into greater detail in Understeer (with diagrams and everything!).

My ( limited ) understanding was that a good mineral could be as good as a synthetic but a synthetic will keep its properties much longer and therefore allow longer service intervals.
I change my oil and filter once a year ( usually a day or two before the nationals! ) approx 1500 miles. It's hardly dirty when it comes out!


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balmy wrote: Mon Mar 13, 2017 2:09 pm My ( limited ) understanding was that a good mineral could be as good as a synthetic but a synthetic will keep its properties much longer and therefore allow longer service intervals.
I change my oil and filter once a year ( usually a day or two before the nationals! ) approx 1500 miles. It's hardly dirty when it comes out!


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Sort of... but... (EDITED AS I MISSED THE FIRST BIT)

Mineral, Semi-Synthetic or Synthetic base stocks

Base stocks are either mineral based, semi-synthetic, synthetic or vegetable based. Most motor oils were mineral based until the late 1990s when synthetics became more widely available at more affordable prices and now tend to dominate the passenger car motor oil market. On an industrial scale mineral oils still predominate with syntehtics being used for exceptional cases that demand the use of a synthetic base oil.

Mineral oils now fall into three main blends as categorised in Table 1 below. Improvements in blending of the base oils has reduced some of the problems that were typical of oils in the 1960s and 1970s. Depending on the level of refining, mineral oils can still suffer from inconsistent molecular sizing, weakness of unsaturated bonds and impurities such as Sulphur and Aromatics leading to shorter oil service life, poor film strength, low Viscosity Indices, and depositing on machine surfaces. Again, though, price will determine the quality of the base stock used in mineral based oils.

Synthetics are derived by a different refining process to offer better performance owing to their consistent molecular structure and purity.
Graphical representation of the difference in molecular sizing between mineral and synthetic base oils.

Advantage of Synthetics

Superior wear control
Superior friction control
Superior thermal stability
Superior aging characteristics
Superior film strength
Higher Viscosity Indices
Superior detergency levels

Translated, that means:

Improved fuel economy or energy utilization
Improved power output
Cleaner machine surfaces
Longer oil life with longer oil change intervals resulting in less downtime
Reduced component wear

What are the downsides to Synthetics?

Basically, synthetic oils cost as much as 3 times the cost of mineral derived oils. In real terms that is the only downside bar potential seal and coating compatability issues. Other issues often given as negatives of synthetics such as seal compatibility and additive solvency can be controlled. Issues such as viscosity being too low or thin are often quoted as a reason for not being suitable often on forums relating to use in a classic car will depend on the selection of the correct oil viscosity grade. Unfortunately in the classic car community synthetics receive bad press for all the wrong reasons.

What about Semi-Synthetics?

The implication is superior performance at a lower cost by combining a mineral and a synthetic base oil stock. There are no regulatory controls on what percentage mix constitutes a semi, so price and performance variation will occur. Do not be mislead into thinking that the price difference on semi-synthetics is simply a marketing ploy, although it may well be, but so-called semi-synthetics can vary between 2% and 30% typically in terms of synthetic base oil content blended with the mineral base oil.

Mineral versus Synthetic

The table below identifies the American Petroleum Institute (API) grading of base oils. Group I, II and III are all derived from crude oil which in effect means these are a mineral base oil. Group 4 is as close as you can get to a mineral oil in nature owing to it's derivation from the Olefins in the gas industry. Group V oils will include all other forms of synthetically engineered oils such as Glycol and Ester based fluids, as well as Silicone fluids.
What does this API Group rating mean to the user?

The higher the number of saturates, the higher molecular bond strength of the oil and therefore the better the resistance to breakdown or loss of viscosity.

The lower the Sulphur content, the better the purity and thus the less the corrosive and oxidation potential that exists.

Viscosity Index (VI) is an indication of the rate of change of viscosity against temperature, and the higher the VI, the better.

Will I find this Group Rating easily?

No, generally manufacturers will refer to either Mineral, Semi-synthetic or Synthetic, but won’t differentiate as to the Group on the information on the oil container. If you dig deep enough to find the data sheet you may find the answer and this is crucial when dealing particularly with turbine oils where these are used in large volumes.

Can a Mineral Oil be called Synthetic?

The answer is yes. With the advances in refining of crude oils, a process of hydrogen cracking is used to ensure low levels of Sulphur, Aromatics and improved levels of saturated bonds. The argument that was put forward and won in the North American market is that this type of mineral base oil is effectively similar to a synthetic oil in performance terms so in effect the marketing department can legally use the term synthetic (a very emotive term) for Group III base oils. Please note that this really only applies in the North American market and not elsewhere.

I use the Halfords Classic,only because it was on offer and I had some vouchers!

Yeh the Halfords classic oil I use. Been using it a couple of years now with no issues.

With my number of cars and the fact CVF burns it faster than it can be extracted I bought a 25 litre drum of Morris (what other brand?!) 20W/50 and haven't had any issues.

I do have a small tin of engine oil with a picture of a Marina on it!

I have used Morris 20w50 oil in my cars for years always found if to be very good quality
Dave

After a few weeks researching and testing some of these mineral oils I've come up with the following information. All oils are not created equal, and you should always read the small print and keep in mind the engines condition.

Can a cheap oil provide all the protection required?

To a degree, but for the superior performance required for more demanding applications a better base stock and more sophisticated additive package are required.

Why is engine oil so much more expensive than other oils?

Mainly because the oil is subject to extreme conditions in an engine compared to other mechanical systems such as gearboxes, axles or brakes, and so requires a better base stock and additive package. These extreme conditions include:

High temperature leading to reduced oil service life as a result of increased oxidation activity.
High levels of contamination from the atmosphere, fuel/combustion and wear debris in that order.
Many moving (sliding and rolling) parts resulting in varying forms of lubrication from boundary lubrication to thick film, in addition to varying metals and varying load conditions all contributing to a more stressful environment for the oil.
This is why the oil is not only more expensive, but generally will not last as long as say a gearbox or hydraulic oils. The additive package can form up to 30% of the volume of engine oil compared to just 1-10% of other oils.

There is also the issue that pricing is set based on the fact that car enthusiasts are sometimes willing to pay a little extra. The marketing of the engine oil products is very emotional with little hard science in evidence at times – the old adage that bull baffles brains applies quite frequently, not helped by incorrect “facts” continually trotted out across the internet in various forums.

How are oils regulated or compared in the industry?

The American Petroleum Institute (API) categorises the formulation of oils according to a standard. Typical engines of the period are used as a test bed, and a number of tests are run to ascertain the performance of oil under test. If it meets or exceeds the parameters of the test then it can be classified in that category. However, oils in the same category do not necessarily have equal performance, they may only meet, not exceed, the requirements of that category. Current ratings are based around standard engine design at the time, so modern oils are designed to withstand higher power outputs, with multi-valve and overhead cam etc reaching higher rpm than previously. This does NOT necessarily mean they are unsuitable for older engines although this is a general guide in terms of selecting oils.

What are these categories?

For petrol or Spark Ignition engines, there is a ‘S’ rating, in which stands for Service. For diesel or Compression Ignition engines, there is a ‘C’ rating, in which C stands for Commercial.

Service Oils aka Spark Ignition Oils:

The ratings started with an API SA rating, and this oil is not recommended for any vehicle in my opinion except vintage vehicles. By the 70’s it had moved onto an API SC rating. During the Nineties it rapidly moved up to as high API SJ, and is currently at SM. The oil required will depend on your driving needs, i.e. daily commuting versus track-day or motorsport driving. For the latter, buy the best you can afford, but for commuting, an API SL or API SJ should be more than adequate on modern cars unless SM is specified by the manufacturer.

Service Ratings – Gasoline/Petrol/Spark Ignition Engines
There has been a recent trend by some experts to suggest not using an API oil higher than SG. The reasoning given is these lack sufficient Zinc protection. As mentioned earlier, Zinc levels are still much higher than they ever were in the SA/SB/SC oils on which the A and B Series would have first run. Certainly, in 1993, in the UK, exhaust catalytic converters became compulsory fitment for vehicle manufacturers, and Zinc is damaging for these. Now API SG is for engines built in 1993 and older. But API is a North American focussed organisation so I am not sure if there is any link between the change in test parametres for SG to SH categories and the UK requirement for catalytic converters which were being used on many cars long before 1993, anyway. The API ratings do state for 199x engines and older and do not specifically exclude engines built before 1979. By rights MGBs should be on SB/SC oils given the date of its original engine, however, experienced engine builders seem to differ in their views regarding synthetics and modern SL spec oils with some praising these oils and some hating these oils.

In fact, as SG is an obsolete category now you would struggle to find an SG oil today, without going to the specialist classic car oils, and these probably won't have been submitted for API SG testing.

This is what the British Lubricants Federation (BLF) has to say regarding advice given to owners of petrol engines:

"Any oil which does not carry an API or ACEA performance specification or some type of approval from a major vehicle manufacturer is highly suspect and must be assumed to fall into the lowest category, i.e. API SA, which became obsolete in the 1930s when the first additive engine oils (API SB) began to appear!

It is essential that oils of at least the correct requirement are used, although higher specification oils, in the same category, should be used as soon as they become available if maximum benefits in fuel economy, engine protection performance and operating costs are to be obtained.

However, it must be appreciated that an engine which has been operating on a very poor-quality lubricant for some time may well be beyond saving, since it is likely to have suffered build-up of sludge deposits which could be displaced by the detergency power of a modern good-quality oil. Blocked oilways could well result.

Currently there is no UK legislation to ensure that all oils marketed are fit for the purpose, although it is the case in some other countries.

Technology has moved on since the 1930s at an enormous rate, and such oils, which are no longer compatible with modern engines, should now be relegated to a museum, along with, for example, mechanical typewriters, ‘cats-whisker radios’, and other 1930s technology."


Here are some favourite oils amongst the Classic fraternity below with their respected data based on my research. Whilst I appreciate this is not a conclusive, or exhaustive list, I have tried to show what is in the oils you use. Remember: Just because a car had a recommended API rating of SE when it was new, does not mean a SN (current) rating should not be used if it is specially formulated for an older engine with high zinc levels and a strong VI rating.


Halfords 20w50 oil (actually Comma Classic)

zinc content: 800ppm (0.08%)
Viscosity Index: 120
Performance Level: SE (API)
-Incomplete data at time of test-

Morris Golden Film 20W/50

SAE Viscosity 20W-50
Viscosity Index (VI) 130
Performance Level API: SF / CC
MIL-L-2104B
Zinc as ZDDP (ppm) 700 (0.07%)
Base Oil Group Grp I
Detergent-Dispersant Package Low
Other -

Millers Classic Pistoneeze 20w50

SAE Viscosity 20W-50
Viscosity Index (VI) 133
Performance Level API: SJ / CF
Zinc as ZDDP (ppm) 1130 (0.11%)
Base Oil Group Grp I
Detergent-Dispersant Package High
Other -

Millers Classic Sport 20w50

SAE Viscosity 20W-50
Viscosity Index (VI) 128
Performance Level API: SJ / CF
Zinc as ZDDP (ppm) 1130 (0.11%)
Base Oil Group Grp III
Detergent-Dispersant Package High
Other

Castrol XL 20w/50

SAE Viscosity 20W-50
Viscosity Index (VI) 120
Performance Level API: SE/CC
Zinc as ZDDP (ppm) 800 (0.8%)
Base Oil Group Grp I
Detergent-Dispersant Package Low
Other -

Penrite Classic Light

SAE Viscosity 20W-60
Viscosity Index (VI) 134
Performance Level API: SG / CD
Zinc as ZDDP (ppm) 1610 (0.16%)
Base Oil Group Grp II
Detergent
Dispersant Package Moderate
Other Includes corrosion protection & tackiness
additive for lay-up periods

VR1 Racing 20W50

SAE Viscosity 20W-50
Viscosity Index (VI) 132
Performance Level API: SL
ACEA: A3 / B4
Ford M2C-153E
GM 6094M
Zinc as ZDDP (ppm) 1300 - 1400 (0.13% - 0.14%)
Base Oil Group Not disclosed
Detergent-Dispersant Package TBC
Other

I just use the normal Comma mineral 20/50.
Change it every year. No issues at all.
As long as changes are done in good time then no need to worry really. I'm guessing that the latest mineral oil will be better performing with better additives than back in the 70's. T

I got a large drum of Castrol
Seems good to me, don't change it every year only after about 3000 miles.