If
you plan to keep your car for more than 5 years then go for best you can afford.
That means synthetic, not semi-synthetic.
For
an intended ownership of 3 years or 60k miles operation, use what's recommended
and then let the next owner worry about it.
Seriously,
if you plan to maintain a Full Service History by having a dealer service for a
3yr/60k ownership, then let the dealer put in what they offer; it should be the
approved oil. That said, I know one
owner of a dealer-serviced prestige German car was dumbfounded after 100k miles
and 6 yrs to find the pick-up strainer blocked with sludge.
Something is seriously wrong there and one suspects that cheap oil was
used but expensive oil paid for in the servicing bill.
Going
for fully synthetic will mean dumping oil at 12 to 15k miles depending on your
service schedule, but that oil may still be good for another 10k if you do a lot
of motorway miles at legal speeds. The upside is that if you plan to run the car
for the next ten years then buy the fully synthetic, it will help ensure optimum
oil performance between services.
Don’t
forget to use good quality fuel to keep the injectors and engine clean.
I
don’t like to be drawn into recommending brands so don’t ask.
There
are a couple of other smaller specialist oil manufacturers who use purer base
stocks that are less susceptible to shearing and provide greater film strength.
These are proven case studies, the motorsport people use names like Motul,
Redline and Royal Purple and independent assessment has shown better wear
protection than even some of the best major brand oils.
On
a classic it may pay of course to just change the oil before and after that
track day session.
Many
people still believe that frequent oil changes are the best way to look after an
engine, which is true up to a point if you do the oil change while the oil is
still warm as it drains out more of the solids and wear debris material from the
system than it would when cold.
If
you are looking to extend the oil drain interval, then a fully synthetic is a
better choice to minimise harm from premature oil failure. Standard mineral and
semi synthetic oils offer satisfactory protection but be warned that they do not
always last the service interval (depending on your style of driving).
This
will vary between manufacturers and oil companies are keen to get this type of
key account. In some cases the
choice of oil is based on tests, in other cases it is purely a commercial
decision. Check with the vehicle supplier what is recommended by the
manufacturer.
In
the case of your classic any oil you use now will be better than what the
factory used in 1960.
Firstly, engine oil is designed to
hold very fine particles of material in suspension.
It has a dispersancy package that keeps the particles finely suspended
and stops them clumping together to form larger. more abrasive and harmful
particles. These particles maybe
fine wear debris from the component surfaces, or possibly ‘soot’, very fine
carbon particles from the combustion chamber that get passed the piston rings
through blow-by on the combustion stroke. If
you look closely at the oil, you can sometimes just about discern the very fine
particulate in the oil. In some cases the oil, when old, may actually feel
gritty to the touch.
Diesels produce a lot of soot
particulate compared to petrol engines and so as a rule, diesel engine oils have
a higher level of dispersancy than petrol engine oils.
In more recent years, Exhaust Gas Recirculation has become normal on many
diesel engines and so there is a tendency for more soot to appear in the oil,
because as unburnt fuel is recirculated back into the inlet from the exhaust,
some soot particulate is dragged through, too.
The oil going black was always a sure
sign that the oil had a good detergency and dispersancy package.
However, on newer engines with tighter clearances and more efficient
combustion owing to the ECU, and partly thanks to modern oils, there is less of
this effect occurring so it will stay clearer for longer.
Your
engine will be stressed a little more than the standard anticipated design usage
and may generate more heat. For safety, extended reliability and reduced wear
rate, superior oil should be used to counter the effects of the modification
work. Essentially, the higher film
strength of a synthetic will reduce the impact of the increased loading from the
extra modifications.
Film
strength is the ability of the oil to support a load without metal-to-metal
contact between the components.
Film
strength at the bearing is dependent on the oil's capability to resist shear at
the bearing. Some of the best oils
are expensive but do offer significant protection despite being a lower
viscosity. This lower viscosity reduces friction from the oil at the bearing
thus allowing more power to be transmitted to the drive-train. This kind of oil
finds favour with motorsport people who are seeing very good engine life and oil
life during a hard racing season.
Another
reason to use a synthetic in a modified car is to allow for increase heat
build-up when the car is used harder, as synthetics resist heat degradation
better.
Being
pragmatic, I say better to have the right level of oil than worry about the
mixing effects over time. However,
always try to stick with one brand as cross-mixing of oils can impair additive
performance. Generally, though, there will be no adverse effects from
cross-mixing brands of oils.
Particularly
on diesels, idling will not allow the full combustion to take place, so wet fuel
remains in the cylinder and starts to run down the bores. This will reduce the
wear control from the oil splashed up onto the cylinder walls, and further, will
accumulate in the oil, lowering the viscosity and reduce additive effectiveness
such as the dispersancy additive, causing larger particles to increase wear
rates. In some cases the dilution can become dangerously high (>5%).
So, start your engine, and move off. But
remember; although the temperature may come up to normal quickly, the oil will
take longer so let the car warm up properly (10 miles minimum) before exploring
the revs.
To
minimise future oil consumption problems, it is advisable to take it easy during
running or bedding in. Some people
suggest town driving is best, and to avoid constant revs in the same gear. If
using the motorway, then drive at speeds between 55 and 70 mph, and also change
gears a few times.
Avoid
synthetic oils during running in, try for 10k miles before switching to full
synthetic oils.
However, the old school of running in an engine does not apply as much these days owing to the fact that the machining processes result in better finishes that do not need bedding in as much and as a result (and also, I suspect, to save money) manufacturers no longer offer a 1000 mile service, instead the engine is on a normal schedule of 12k-15k miles from the beginning. In addition the assembly processes during the build of a new engine are much more automated and the cleanliness is far better resulting in new engines with far less potential for problems from day one.
From
research I was involved with I know that wear can be radically reduced through
finer filtration, and that automotive filters are not rated in the same way
industrial filters are. From testing we did, we found an average 5BHP more on
cleaner engines after 900hr endurance testing. Since wear will influence fuel
economy and emissions, as well as oil consumption, it is better to stick with
better quality oil, fuel and air filters, too. So always ensure you use
the best quality air, fuel and oil filters.
DO NOT USE a fully synthetic until the engine has covered a little more mileage (approx 10k) because the engine is still bedding in for some time up to this point. Then switch to a good synthetic.
What are
the benefits? Less wear, less power loss in the engine, better fuel consumption.
Generally,
the reference to synthetic oil for an engine can mean a Group 3 Mineral
oil. But if it means a lubricant is formulated with a polyalphaolefin (PAO)
base oil, then it is pure and is compatible with mineral base oils.
However,
because the PAO base oil does not dissolve additives as well as a basic mineral
oils, it is usually formulated with an ester co-base (usually di-ester and/or
polyol ester). The additives are soluble with the ester and the ester is soluble
with the PAO.
The PAO tends to cause seal shrinkage and the ester causes seal swelling, so the effects are offset when both base oils are present.
When switching to a fully synthetic on an older engine, or one with a higher mileage, it is the ester that can cause problems when one changes from mineral to synthetic. Ester base oil used alongside PAO base oil in lubricant formulation has excellent natural detergency. In other words, it will clean up deposits on component surfaces as a result of thermal and oxidative degradation of the lubricant. When one switches from typical mineral-based engine oils to a typical synthetic-based oil, the varnish layer will be removed by the ester in the synthetic oil and become suspended.
This suspended material can rapidly clog filters and can potentially block oil flow passageways and lead to component starvation. The same is true for gearboxes and other industrial machines. So think twice about switching to synthetic oils in applications where the engine or other machine has been operating for some time with mineral oils. It can be done but be aware of the potential for creating more harm than good.
This
is also where oil seal leakage can be an issue as the beneficial layer of
deposits on the seal are holding the oil in, but once cleaned off, the seal can
initially shrink before settling again, so a short spell of oil leakage may
result.
On rebuilt
engines of the older type, such as the MGB, the same applies, allow for bedding
with a standard oil, and then switch to a synthetic, although there is some
concern that the higher detergency will not allow a beneficial depositing on
seals and as such, the oil consumption may prove a problem.
In my experience, with Mobil1 oil consumption has been no worse than with
mineral oil and that’s using 0W40 in my 1980 MGB GT.
Generally, if stored in a dry, moderately stable area with regard to temperature, then oil can last a long time. However, additives can settle out after a period and so recommended best practice in industry is for a maximum shelf life of 12 months. In a domestic situation, 2 -3 yrs would be acceptable assuming it has been sealed. I would also suggest shaking the container prior to use to help re-suspend the additives that may have settled out.
I know that experts will say the oil can be stored for much longer, but allowing for the fact that the oil is often blended and packaged up to 2 years before you buy it, then the limit of 2yrs is a good safety margin. Hopefully the oil will have been in good storage conditions in the retail stage between the blending plant and your car, but don't count on it either.
The same is true of grease, in fact the recommended storage is less, at 6 months in industry. Again, for home use, 2-3yrs is ok, and possibly longer assuming your garage is dry and relatively protected from low temperatures. However, a problem known as bleed happens with grease, and so it is advised to always store the grease gun and tubes of grease horizontally to avoid the oil bleeding off to the top of the gun or the tube.
Any containers of grease should be kept sealed between use and if it doesn't have a loading/feeder plate on the surface of the grease then lay a sheet of plastic over the top to minimise the exposure of the grease to the air.
Brake fluids should not be stored for more than 2-3 years and only if unopened and the foil seal remains intact. Any fluid already opened will have a shelf life of less than 6mths, possibly less if stored in the boot of your classic.