Sludge and lubricants

[Scruggs Family]

Hi Grant, 

The area of automobile lubrication is indeed a complex field that has more
corners on it than can be addressed in this forum where knowledge and
experience is not a level playing field.  The thing that we've both avoided
is how the automobile in question is being used.  Mom taking the kids to
school and soccer clearly requires shorter change intervals than the
commuter that drives 60 miles a day on the freeway.  The latter has been my
mode of use for about 25 years... thus my liberty with an extended change
interval.  Constant engine temperature is the key here and one could run
very long oil changes in an engine that is in constant use.  The Amsoil
literature occasionally documents long haul truckers using their synthetics
for 100k miles before a change.  

The formulation of engine lubricants is a corporate compromise intended to
cover a range of usage patterns and is likely not optimal for mileage and
temperature extremes.  Of course the manufacturers recommendations are a
compromise between meeting the expectations of the typical user and the
desire to sell more oil.  

One thing that many misunderstand is that oil does not wear out... is simply
becomes contaminated resulting in diminished lubricity... thus my point
about the reduction of additives being a positive contributor to longer
change intervals.  

While in aeronautical engineering school in the late '70s I found a book in
the school library that documented the origins of synthetic lubrication.
Germans scientists, in the early 1930s, were apparently the first to
formulate synthetics believing that should there a war their petroleum
stocks should be used more for fuel vice lubrication.  I was amazed at the
hundreds of specific lubricants that were developed during that period...
only very few of which were suitable for automobile use.  Lubricants for the
developmental aircraft turbine engines were high on the list of goals during
these times and synthetics are used exclusively in those engines to this
day. 

The relating of my experience is in no way a recommendation for anyone else
to follow but merely a documentation of what, for me, has been a successful
use of synthetic lubricants.  

As they say... 'your mileage may vary.'  

Gross



-----Original Message-----
From: Grant Lenahan [mailto:glenahan at vfemail.net] 
Sent: Monday, November 01, 2010 7:44 PM
To: Scruggs Family
Cc: quattro at audifans.com
Subject: Re: Sludge and lubricants

mostly agreed. I've posted pages and pages on oils on various sites. But my
point is that while the synthetic base does not deteriorate as quickly
(mostly due to fewer VI improvers), they still lose good additives like
anti-foam, anti-wear, detergents, anti-acid, etc.

And acids and petroleum distillates do build up. So even if you had perfect,
permanent, last into he next century synthetic oil , you sould still either
change it or become a formulator and add your own additives, then take the
oil out and centrifuge out the impurities.

So the fact remains, they can be extended, but even synthetics require
changing by 1 year or ( it varies) 5-10k miles.

I would avoid 20k on any car that uses oil hard, such as a 1.8t.

For instance, a car like my boxster or S6, with > 8 qts in the sump, can go
longer than a 1.8 with 4.3 qts in the sump.

I would never go 20k

Grant

On Nov 1, 2010, at 4:40 PM, Scruggs Family wrote:

> Grant, while your comment is correct it steps over one of the vital
reasons
> for using synthetics... they have far less additives than petroleum bases
> lubricants.  Petroleum oils typically have 20% of their volume in
viscosity
> improvers, pour point depressants, antioxidants, etc.  Synthetics... the
> good ones... have a little as 5% of the same additives.  Essentially, with
> synthetics there is less in the mix to wear out and contaminate the
> lubricant.  
> 
> I first used synthetic oils in '77 in my Rover 2000TC.  I've used
synthetics
> exclusively since '85 (even in the lawn mower) and have had no problems,
> noticeable wear or increased consumption using 20k mi change intervals.
> That's about 600kmi over 6 cars/trucks.  I do, however, change filters
every
> 5k and top up the level.  
> 
> Gross Scruggs
> Annapolis MD
> 
> 
> Message: 1
> Date: Mon, 01 Nov 2010 14:45:09 -0400
> From: Grant Lenahan <glenahan at vfemail.net>
> Subject: Re: How to check for sludge ?
> To: Ed Kellock <ekellock at gmail.com>
> Cc: 'thejimrose' <thejimrose at gmail.com>, quattro at audifans.com
> Message-ID: <4CCF0AB5.1050002 at vfemail.net>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
> 
> yes, they do. But bear in mind that oils deteriorate for many reasons, 
> and even with synthetic you must consider:
> 
> 1. depletion of additives
> 2. accumulation of acids
> 
> Neither is affected by teh improved base stock
> 
> Grant
> 
> 
> 
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Grant Lenahan
glenahan at vfemail.net