Randall Young wrote:
> However, full synthetic has been available for some time
in 20W-50, which
> should be plenty thick enough for our old engines. I've
in fact been
> running my TR3 (rather hard at times) on it for several
years with no
> apparent ill effects.
Point taken on the 20W-50, Randall and no argument with the
thickness/viscosity to old engines.
Michael Porter wrote:
Keep in mind that John Macartney's original post on this
subject was to
pass on the wisdom of the oil manufacturers themselves that
contemporary
full synthetics are not recommended for use in older
engines. Maybe they
know something they aren't fully advertising to the general
public,
either about oil additives, oil properties, or both.
This is where there could well be a divergence in what is
defined as a synthetic. I can't speak for the inevitably
vast range/brands of oils sold in the US. From a UK
perspective and I think this applies for Europe too, we have
a particular dilemma which is confusing the consumer. This
MAY apply on the other side of the pond as well.
Hitherto in the UK, we've had broadly two types of oil - one
is pukka full synthetic which is a totally engineered
lubricant and used in Formula One racing engines. The other
is a high grade mineral basestock to which are added certain
elements of synthetic to enhance the overall oil quality.
Many people assume (wrongly) that this is a synthetic and
obviously it isn't. The third and relatively new group is
what we call a hydrofinished or hydrotreated oil. This is in
fact a mineral oil which, I am told, has a significantly
enhanced basestock with further synthetics added to it.
Within the UK, this hydrotreated lube is often seen as a
true synthetic and there is evidence that it's being passed
off as a full synthetic (under a little known brand name)
and again, it isn't. One way and another, the picture in
Europe is fuzzy to say the least.
On oil classification, there are further fuzzies and I can
best illustrate this by quoting part of a paper published by
Rover Advanced Power Train Development
"Most marketers show a range of performance classifications
on their cans - but there is no LEGAL requirement for them
to be current ones, so these often appear on older oil
formulations. By example, it is not unusual to find an oil
quoting "BLS.OL.02" which has been obsolete for at least ten
years! The American and European classification systems have
rules to try to prevent oil marketers making claims about
obsolete specifications.
The main classification systems are:
American: API (American Petroleum Institute)
European: ACEA (Association of Constructors of European
Automobiles)
Manufacturer specs: Rover, VW, Mercedes Benz, Ford …
There are some other classifications and these deserve
mention:
MIL an American Military specification
ILSAC a joint American/Japanese system. Tends to be adopted
by API
CCMC the old European system replaced on Jan. 1, 1996 by the
ACEA system
The ACEA and ILSAC systems have standards set by the motor
industry in consultation with the oil and additive
industries. The API system is based on balloting by members
of the American Petroleum Institute, so tends (in the
European motor industry's view) to be less driven by the
engine's needs.
API The American system
This has two categories. The "S" oils are for petrol engines
and the "C" oils for diesels. In each case, the second
letter in the code shows how recent the specification is.
On petrol engines, SA, SB, SC, SD, SE, SF and SG are
obsolete. SH is fairly recent but SJ is the current
standard.
On diesel engines, CA, CB, CC, CD, CE and CF are obsolete.
CG is current
CF-4 and CG-4 are designed for use in American trucks and
CF-2 for 2-stroke diesels.
ACEA The European system
There are THREE categories in the European system.
The "A" series oils are for petrol engines, the "B" series
for light duty (car/light van) diesel engines and the "E"
series for trucks.
The number after the letter shows the performance level.
A1 oils are for the new generation of petrol engines
designed to operate on light fuel efficient oils. They are
NOT suitable for all current engines and certainly not
suitable for engines in 'classics.'
A2 oils are the mainstream oils for petrol engines and the
ones most suitable for 'classics'.
A3 oils meet all the requirements of A2 but have to meet
higher standards in some of the tests. They are higher
quality oils for use where manufacturers have special
requirements, for instance in high performance engines and
especially those fitted with turbochargers.
AVAILABILITY
The American API system is probably still the most widely
used across the world but all European car companies use
ACEA specifications. Even the US car manufacturers tend to
require oils to ILSAC specs, rather than API.
The availability of oils to each set of requirements tends
to vary according to where the European or American
influence is greater.
Generally speaking, oils that meet ACEA requirements will
also meet API - but many oils meeting API standards will not
necessarily meet ACEA."
ENDS
It's my guess that last paragraph ought to cause a bit of a
stir with informed listers (and I didn't originate it) - but
what appears to be happening within UK/Europe is this. On
the premise an API standard may not exactly translate into
the current ACEA standard (or the former CCFC standard),
there is some evidence that certain lesser known (in some
cases entirely UNknown) smaller oil marketers are passing
off a so-called synthetic under an API reference. One found
recently was graded as API-SC - a long obsolete standard -
yet the packaging claimed it to be a full synthetic! As API
is a recognised designation in Europe (though not
necessarily understood by the person who reads it) it is
assumed the oil fully meets a spec that will be suitable for
use in a 'classic' engine.' This is where the problems have
arisen with seal erosion and undue washing of components by
oils with an excessive detergent level. These are the
problems we are having in Europe and to attempt to compare
US API standards to ACEA equivalents for 'classic' engines
will be rather pointless. The point I was trying to make was
that as far as we are concerned in Europe, oils as a whole
tagged synthetic - whether full/partial or hydrotreated with
high content synthetic components are generally not suitable
for our type of engine. Finally, while I have every
confidence in Mobil 1 for my daily driver (three years old
and with a modern engine requiring a 'thin' oil) there is no
chance of it ever going in my Triumph. I don't use Mobil 1
anyway because at $36 for 5 litres its too damned expensive!
The tolerances on the Triumph together with other cars of a
similar age are too great and this could easily lead to
component failure. The message Gaydon is putting out is to
go for an oil brand and blend type which was common 20 or
more years ago. Very likely it won't be identical to the
original blend because there may well be some additional
rust inhibitors and anti-wear agents (but NO synthetics)
that will only enhance the oil performance and life without
adversely affecting the viscosity which should still be
20W-50. Even a modern 15W-40 is considered too thin.
Jonmac
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