Re: Bipass Oil Filtration Systems

[alex.fadeev@xxxxxxxxxxx]

"John Bolhuis" <bolhuijo@domain.elided> wrote:
> On Fri, 17 Jan 2003, Stephen Hutchison wrote:
> 
> > Does anyone go to the extent of running one of theses systems
> > on a BMW? The logic makes sense, but is it really practical 
> > or needed?
> > 
> > Amsoil makes a neat one that combines the full flow and bipsass
> > filter on one remote mount which is connected to a spin-on 
> > adapter plate at the normal full flow filter location...
> 
>  The logic is that the by-pass filter removes particles smaller 
> than 1 micron, on the theory that particles in the 5-20 micron
> range are responsible for 60% of all engine wear.  Full flow 
> filters only filter down to about 25 microns.

John, 
Oil bypass is a spring loaded devise in the oil filter that opens up when 
the filter gets clogged. The idea is that it's better to oil the engine 
with unfiltered lube than not at all. 
Are suggesting filtering that bypass channel? 
Or are you saying that all stock filters suck and a finer particle filters 
are the only thing that will save the engines from impending demise? 

>  This is great if you drive a lot of miles, want to maintain the
> highest standards of cleanliness, and like the long drain intervals.
> Some of these guys are going 2 or 300k miles with only filter changes.

That's crazy.
Sorry if that is too strong a language for some of the readers.
Any oil, including synthetics, breaks down in the 3-25K range. Engine 
operating conditions have a lot to do with it, so milage alone is not a 
good indicator of oil degradation. 
Most people (not selling oil) recommend replacing synthetic oil in the 
5-7.5K and filter in 5-8K intervals. In fact, that is exactly how my '95 
M3 counts the oil change intervals. '96+ M3 were covered by the BMW 
maintenance warranty and their oil change intervals were suddenly extended 
to 15-18K miles before changes. A coincidence, I'm sure ;-)

> The downside is extra plumbing, meaning more places for oil to leak
> out.  Also, if your engine is still ok at 250k miles with normal
> maintenance, one would argue what's the point?  The body is probably
> falling off at that point anyhow.

We have a member in our Lone Star Chapter with a 750+K '77 5-series. The 
body still looks good, though the paint is long past faded. The engine was 
rebuild once at 650K miles. 
The oil and the filters weren't half as good 25 years ago. For the engine 
to have lasted that long, I would guess the filtering must have been at 
least adequate. 
But than this is the first I'm hearing about stock oil filtering 
inadequacies and am yet to research the subject. 

curious,
alex f

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