> -----Original Message-----
> From: owner-triumphs@autox.team.net [mailto:owner-triumphs@autox.team.net]
> On Behalf Of Shrack04@aol.com
> Sent: 12 October 2004 15:48
> To: triumphs@autox.team.net
> Subject: Castrol
>
> Any bad things about using Castrol full Synthetic oil? What is it made of
> anyway?
Well I can't tell you what it's made of, but my wife Karen spent 10 years
working as a development chemist for one of the major oil companies (though
NOT in the development of engine oils).
She says:
"Fully synthetic oils use a class of organic chemicals called Esters as the
major component, or basestock. Conventional oils use mineral oil as
basestock, this is long chain hydrocarbons refined from crude oil. The
clever bit about synthetic oils based on esters is you can design the
properties of your basestock. Esters are formed by reacting a carboxylic
acid with an alcohol, by choosing the length of hydrocarbon chain on each
(this will make the alcohol or acid bit longer or shorter) you can change
the properties of the final product. Small esters will be more volatile and
thinner, large ones less volatile and thicker. A mixture of the two
properties would be desirable in an engine oil, to achieve a multigrade
performance.
Esters are used as they are more stable to oxidation than mineral oils (the
thick black bit of used engine oil is mostly oxidised basestock). They can
also enable different additives to be used than in mineral oil. The main
problem is that they are much more expensive than mineral oil, when I was
still in the industry mineral oil was about 30p a litre, esters were upwards
of #1.20 per litre. Obviously this makes the finished product a lot more
expensive.
If you're wondering whether to use fully synthetic, it's up to you. My
preference is to use mineral oil based lubricant and change it every 3,000
miles - for most Triumphs this will give the same performance as synthetic
and at less total cost. Bear in mind that synthetic oils tend to be lower
viscosity to start with and may well find their way around the seals
designed for 20W50 tolerences!"
Hope that helps,
Cheers,
Bill.
Rarebits4classics
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