I use Mobil 1!!!!
Back in March, I spoke to a scientist for a major oil company.
She tells me that mineral oils *start* to break down at 88C (190F)
whereas synthetic oils *begin* to breakdown at 200C (392F).
Note these are the temperature at which the first traces of breakdown
happens. The rate would be very low at those temps, but at the hotter
parts of your engine (e.g. rings), the rate of breakdown would be
considerably higher because the local temperature is much higher.
Byproducts of mineral oil breakdown include acids and carbon soot.
The carbon soot tends to fall out of suspension causing deposits
throughout the engine. Byproducts of breakdown in synthetics remain
in solution (hence no deposits)This is why 5000 mile oil changes were/are
recommended on conventional oils - the oil has been slowly breaking
down since the engine was first turned over. This is also why 25,000 mile
oil changes were recommended for synthetics - they didn't have the quantity
of breakdown by-products and any by-products just remained in solution
anyhow.
So, personally, I think this clearly sends two messages
a) if you use mineral oils, an oil cooler is a pretty damn good idea.
b) you should seriously think about using synthetics! I have been doing
so for the past 6 years in my race and rally cars and I have no complaints!
I should say that I do use penrite HPR30 in my road 1100 (was a daily
driver)
and in my tow cars. Why, well it still is a very good oil and these engines
all have
lots of miles on them since the last rebuild. I did not want to swap over to
Mobil 1
on high mileage motors since lots of crud can get picked up and pumped
through the engine, causing more damage than benefits.
Mike
Conventional oils *start* to breakdown at 190F. Sure the rate of breakdown
is low
but this means
----- Original Message -----
From: <Daniel1312@aol.com>
To: <mikeg@vicnet.net.au>; <spridgets@autox.team.net>
Sent: Tuesday, 26 October 1999 5:16
Subject: Re: STP & engine temperatures
> Sounds reasonable so why do some people use Penrite?
>
> Daniel1312 - Mobil 1 user
>
> In a message dated 25/10/99 11:57:30 GMT Daylight Time,
mikeg@vicnet.net.au
> writes:
>
> << Since synthetic oil doesn't start to breakdown until a much higher
> tempertaure than conventional oils, they will not see the buildup of
> failure by-products around the rings. >>
>
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