Oils/Lubricants

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Classic or contemporary, with today’s engine oils you simply can’t use just anything and go with the flow. Here’s why you need to make a classic choice

It used to be so simple back in the good old days. If you needed engine oil you just popped down to your local motorists’ shop and bought Castrol GTX or Duckhams Q. But now with more than 100 different brands and blends of engine oil on sale it’s oh so easy to use the wrong oil and do more harm than good as a result.

In fact, so specialised are some of today’s advanced lubricants that an increasing number even have their own part number at main dealers, meaning that if you use the wrong oil you’ll probably invalidate the vehicle’s warranty!

We all make mistakes and even seasoned mechanics not only fail to fully appreciate a lubricant’s role but are also ignorant of what’s the correct oil for your car.

According to Comma Oils, a 10W/40 grade oil remains the most popular pick, accounting for 42 per cent of sales, and yet only 12 per cent of vehicles now require this grade – meaning almost a third of us are using the wrong lubricant. There’s also seven types of 5W/30 too, so even when you think you’ve got it right you haven’t…

BTN Turbos claims a staggering 91 per cent of warranty claims are purely down to motorists – and mechanics – using the incorrect oil for that particular engine.

SLIP SLIDING

Engines may have evolved over the decades, but the basic role of their lubricant hasn’t and that’s providing an indispensable protective shield between the engine’s sliding surfaces, which although look and feel silky smooth to touch, are as jagged as the lunar surface under a microscope.

Without a film of oil, an engine will seize in seconds. Plus oil also cleans away harmful by products such as acids, coke, tarnish deposits and so on and must do so for thousands of miles under all extremes of driving conditions, from cold start school runs to fast drives up the M1.

WHY CLASSIC?

On the face of it, you’d think that the newer, more advanced lube then the better but this is not so because, after certain specifications and formulations, it won’t protect your classic’s engine any better – in fact perhaps the opposite is more true.

The very latest oils major on emission control and are blended as such. For example, to prolong the life of a catalytic converter, today’s oils have severely cut down on their zinc (ZDDP) contingent, which is fine, except that zinc is a fine anti-wear agent and so its reduction can lead to excessive piston ring and camshaft wear.

At the other end of the scale, a plain budget 20W/50 oil may well have been designed when the MGB was in the showrooms 50 years ago but its specs and quality are far too inferior to what’s demanded half a century on.

A classic oil strikes the perfect balance for classic lovers, providing current standards of quality but twinned with traditionally refined formulations for the eras these oils were intended for.

CODE CRACKING

How do you tell a good lubricant? Check out any good quality pack of oil and you’ll probably see a lot of numbers and letters. To the uninitiated it looks very confusing, yet in fact this coding is pretty easy to crack. ‘ACEA’ (a respected European governing body) ranks oil quality from A1/B1 upwards (A standing for petrol, B for diesel).

A more familiar standard is the American API body which uses plain lettering. S stands for ‘spark’ meaning petrol (C for ‘compression’ diesel). SN is the most current standard but you can still find SF ratings which was first introduced some 40 years ago.

And look out also for listed approvals from leading carmakers which is taking more prominence as carmakers increasingly demand a special oil for their engines; it’s reckoned that the Germans (BMW, VW, Audi, Mercedes and Porsche) remain the fussiest and as a result their rubber stamps are highly valued on an oil’s pack. Similarly, you see Ford-branded Castrol oils made especially for its engines.

Failing this, check out the websites of the oil marketeers such as Castrol, Comma etc; Halfords stores have an easy point-of-sale store guide along with helpful coloured oil packs, too.

PLAYING IT STRAIGHT…

The traditional ‘multi-grade’ that’s universal came about thanks largely to the Mini which used the same engine oil to lubricate the transmission as straight oil grades weren’t suitable. Before this, straight oil grades were the norm and had to be changed to suit the seasons with a lighter ‘20’ or ‘30’ grade for winter and a thicker lube for the summer.

Again, referring back to our earlier comments concerning oils right for their engine designs and eras, classics dating back to the 1940s may be better off with a ‘monograde’ oil – indeed some air-cooled VW enthusiasts will use nothing else still! Also certain old engines shouldn’t use an oil which contains detergents; speak to your specialist or car club for advice.

...AND MAKING THE GRADE

To even the initiated, motorists recognise oil by its name and the numbers (technically known as viscosity, to the layman thickness) it carries. We’ve all heard of 10W/30 and 20W/50 (‘W’ means Winter) and in the majority of cases this is what your classic will happily run on.

The first major change occurred in the mid 1980s with the advent of Performance Oils (semi or fully-synthetic) to counter what was known as ‘Black Death’ sludging. During this decade, oils became thinner and more specialist. A phenomenon known as ‘valve stick’ plagued certain engines in the 1990s and led to ultra thing oils – now as thin as 0W 20 for today’s engines!

However, the oil’s thickness doesn’t automatically mean it is a better protectant and using a thicker grade in an engine not designed for it can cause problems as it struggles to pass through oil ways and working tolerances not designed for it, especially when it’s cold.

The exception is when the engine is worn and burning oil. Here a slightly thicker lube – say the next grade up – can help reduce the problem as well as improve flagging oil pressure.

It’s here a classic oil can help as they are invariably fuller-bodied and you can opt for a 20W/60 or 10W/60 oil if desired.

CLASSIC CHOICE

As modern oils become unsuited to older engine designs, the popularity of classic oils has soared as a result and as a consequence so has the range of brews available. What started off as a simple 20W/50 lubricant has expanded to a range embracing various viscosities, oil quality, synthetic types and even special motorsport brews!

While not half as complicated as mainstream choices, you do now need to speak to a classic oil specialist (Penrite, Millers Oils, Morris Lubricants, Valvoline, Castrol, etc) to see what is right for your vehicle.

SINFUL SYNTHETICS

Synthetic oils first came to prominence in the early 1970s but were specialist and didn’t become a high street option until a decade later with the introduction of Performance Oils. There’s two types, semi and fully-synthetic and essentially these man-made oils are superior because they can be brewed and blended from scratch plus boast a wider working range and are longer lasting in service.

Sounds great, but they may not suit oldies. For a start, unless you opt for a classic type, they will be lighter and thinner, and on old engines with their wider production tolerances this will lead to low oil pressure and probably excessive consumption.

Also, by design, synthetic oils are cleaner living and have a dredging effect, so disturbing old latent residue in the engine, which after all these years, is better left alone. If you insist on going the synthetic route (and for many owners, it’s a waste of time and money), then you will at least have to flush the engine out beforehand and possibly drop the sump to clean out any muck – you’ll be surprised the amount in there!

THE PRICE OF PROTECTION

We’re staunch fans of classic oils but have to admit it comes at a price. Top quality lubricants – contemporary or classic – are premium-priced and a typical sump load for a Jag Mk2 will cost you a handsome £80 or so. And as classics are used infrequently, it is advisable to change it annually, especially before a winter lay up, so any corrosive by-products of combustion are expelled. As a result it’s a fair old outlay.

In the end, it depends how much you value your classic. A rebuild on an XK engine costs some £5000 so, in the grand scheme of things, it’s really cheap insurance, isn’t it?

ROUGH GUIDE TO ENGINE OILS

MONOGRADES

Designed for vintage and veteran engines, especially those featuring roller bearing crankshafts or sleeve valve units

Some pre-1940 engines must not use detergent oils so check with an expert first before simply using any straight lube

20W-50 (20W-60)

Popular choice for classics but go for with SF level quality at least

Some specialist lubes boast a fuller-bodied “60” viscosity rating to retain oil pressure under load and control oil burning on worn engines

10W-40 (SEMI SYNTHETIC)

Ideal for modern fuel-injected, catalysed multi-valve engines and GTis made during the 1980s and beyond

Cheaper quality mineral oil alternatives are also suitable for most cars produced during the ’80s; again it’s the quality standards on the pack that matter most

15W-40

Correct grade for mainstream engines from the 1980s onwards – such as later Minis, Sierras, Golfs and so on

There’s a huge choice at wildly varying prices; ignore the brand name (within reason, of course) and concentrate on the specs on the packs instead

ANATOMY OF A CLASSIC OIL

Classic Light is a typical oil aimed at classics. It’s an SAE 20W-60 as opposed to the usual 20W-50 grade. This means that it is as pump- able around the engine at start up or in cold temperatures but has the advantage that it is thicker at operating temperature, thus providing better sealing, oil film thickness and pressure. It’s a “full zinc” product meaning it provides the sacrificial wear effect that older engines were designed around. The zinc ‘plates’ the metal surfaces and is worn away sacrificially instead of the parent material. Modern oils have much lower level of zinc as tolerances and materials are very different. A classic oil also contains tackiness and anti-corrosion additives. This means that the oil stays in-place on the interior engine walls during lay-up times (such as winter) and avoids internal corrosion.

OIL’S WELL

* Change the oil regularly – despite the high cost of quality lubricants they are a cheap insurance

* Oil accounts for up to a third of the engine’s cooling capabilities, which is why it’s important to keep the oil clean and topped up

* Known names and favourite brands are part and parcel of purchasing choice but it’s the specs on the oil pack that say the most; a cheaper lesser known brand that’s boasting all the right labels is as good

* Additives are a personal choice but we’d always opt for a quality lube rather than a cheap oil bolstered by an additive

* An engine flush is a good idea to remove any harmful sediments which are building up, as is dropping the sump pan to clean the oil strainer • Engines featuring hydraulic tappets can run poorly if the old oil has caused sludge build up which can lead to oil starvation

* Don’t use a dedicated racing oil on the road – it’s an overkill. Certain types such as Castrol R is a vegetable oil and won’t mix with normal stuff and coagulate plus is unsuited to cold and low speed running. Also some, such as Valvoline’s 20W/50 contains a lot of zinc which can lead to higher emissions and perhaps an MoT failure on this point

* It’s not just engines that can be given the classic touch. Transmissions and greases are also available and the same reasoning and warnings apply. There’s also running in oil which is a deliberate low quality lube for controlled bedding in. Laying your car up this winter? You can opt for a storage oil which gives off a fine mist to coat the inners during lay up