Castrol Classic Oil. For All Pre 1980 Cars

An article by Castrol Oils
December 1996

Established in 1899, originally as C.C.Wakefield, Castrol launched their first lubricant for cars in 1906 and have been at the leading edge of motor technology ever since. Choosing the right lubricant for your cars' engine gearbox and axle is essential for ensuring peak running and maximum wear protection. The technology of older vehicle engines is dramatically different from today's modern cars, so to assist the owners of older vehicles, Castrol has re introduced their older brand names in a range of 'Classic' lubricants to the correct formulations and importantly, to the precise viscosities as originally recommended by the vehicle manufacturers themselves.

For today's owners, selecting the appropriate lubricant is simply now a matter of referring to the vehicle's original handbook and using the named Castrol brand listed therein. Until now, owners of older vehicles have been forced to choose from a confusing array of multigrade oils on garage forecourts and in recent years, from oils offered by lesser known companies, marketing multigrade formulations purporting to be suitable in instances where monograde lubricants of particular viscosity were originally stipulated by the vehicle manufacturer. Castrol's oil recommendation records date back to the late eighteen hundreds and detail all lubricant specifications for engine oils, gear oils and greases right through to today's modern day classics, so owners can simply refer to their vehicle handbooks or telephone Castrol Oils on 01954 231668 who are pleased to advise.

The Importance of Using the Correct Viscosity Lubricant.

Using an oil of the viscosity recommended for a particular vehicle is important, as it is the oils' viscosity that determines its ability to flow. A quick flowing oil (one of low viscosity) deposits a thin film on the engine's internals, whereas a slow flowing oil (one of higher viscosity) deposits a thicker film. Furthermore, temperature will affect oil viscosity and thin the oil at higher temperatures and provide less protection than required. To compound matters even further, some oil viscosities are more affected by temperature than others and therefore using the correct viscosity oil is important: Too high a viscosity and excessive drag will cause the oil to heat up, additionally when starting an engine using an oil of too high a viscosity the lubricant will be unable to reach areas requiring lubrication quickly enough and rapid wear will result. Too low a viscosity and the oil will provide inadequate lubrication and protection at high temperatures, when under pressure - in fact at all times. The viscosity classification developed by the Society of Automotive Engineers of America (SAE) is universally adopted by both oil companies and motor manufacturers and recognises the following grades:

Monogrades
SAE 5w, 10w, 15w, 20w, SAE30,40,50 & SAE 60.

Multigrades
SAE 5w/20, 5w/50, l0w/30, l0w/40, 15w/40, I5w/50. 20w/50 & l0w/60.

(The "W" following the number denotes Winter and indicates these grades being suitable for use in cold climatic conditions).

The secret of a good oil is its formulation
The blend of oil and the chemical additives which provide it with its particular character and safety margins.

Choosing the Correct Oil for Your Classic.

The formulations required for modern vehicles are very different from those needed for older vehicles. Oils for modern engines comply to the latest API ratings of SG and SH and are ideal for the design of a modern engine, i.e.: use of neoprene seals, high delivery pumps, narrow oil galleries, high revving with overall tighter machine tolerances. A classic car engine has the opposite characteristics with cork/graphite/ rope seals, low pressure cog driven oil pumps, wider oilways with greater dependence on 'splash and cling' lubrication, lower revving with lesser machine tolerances. Such a widely different specification demands a totally different lubricant. Castrol's Classic range of formulations for older vehicles have been specially blended for the work they have to do. Two oils of the same viscosity supplied by different oil companies can have radically different formulations, and thus have significantly different performance characteristics. The particular quality of the oil depends ultimately on its formulation - the special range and quantities (sometimes critical) of additives which are blended with the base oil. Therefore as a guide, remember that a low cost oil cannot be a quality oil as inevitably additives, blend and research may be reduced or omitted to achieve the price, and that a high API rating does not denote suitability for your classic.

For example inadequate detergent will result in gum and lacquer clinging to the hotter engine components - Too much detergent can cause a build up of metallic ash in the combustion chambers of older engines. In older engines with a traditionally high oil consumption, this will cause detonation and pinking. In older engines where the carbon has built up over a number of years the detergents can also have a scouring effect causing the carbon to flake off, blocking up oil galleries and spray jets. High levels of detergents will 'wash' traces of carbon from seals and gaskets, revealing leaks. Inadequate anti-oxidant and the oil will permanently thicken during high temperature motoring, with large amounts of gum and varnish clogging filters and piston rings. Inadequate anti-wear additive and the oil film between moving pans breaks down prematurely resulting in metal to met al contact and irreparable damage. Inadequate corrosion inhibitors and engine internals become pitted with corrosion and rust from acids and water formed during combustion. Inadequate dispersant results in soot, wear materials and the by products of combustion settling out in the sump to form a thick sludge, that will block filters and oilways Inadequate pour point depressant and the oil ceases to flow at low temperatures, with excessive strain on the oil pump or, in certain cases, oil starvation on start-up, causing complete failure of the lubrication system. Castrol's 'Classic' oils are formulated in the style of the original classic oils using the most appropriate additive technology to provide the best protection for your classic engine.

The Castrol Classic Range is available national from over two hundred and fifty of the country's leading marque specialists and a leaflet detailing over thirty-five lubricants for older vehicles with details of stockists and specific lubricant recommendations is available from Castrol by telephoning 01954-231668

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