<< Lynn,
> Thanks for bringing the focus back - even a Fram is better than nothing,
> or a piece of window screen. Even though I use a bypass filter on my car,
I
> don't plan to run on in the air. We aren't 'Joe public' with no clue where
> the dipstick is, so I don't expect that our engines will be producing
enough
> crud, even on a bad day, to plug a filter and push it into bypass. As long
> as we don't go to WOT right after startup with petroleum oil in the
> winter... I still think I'd rather have a bypass valve, if for no other
> reason than when a cold start coincides with a 'senior moment' (and an open
> throttle)...I'd rather have dirty oil circulating than no oil.
>
> To add insult to injury, different brand filters may be made by the same
> company to different specs, and the same brand filter may have been made in
> two different factories to different specs. Bosch filters we can buy in
the
> 'States are different animals to the ones I used to buy in Germany, for
> example...and may even be different than a Bosch filter available to our
> friends in Canada. Champion Labs makes a number of filters, but the
> non-premium filters don't come off the line with the Mobil 1 media inside.
> It can be a challenge figuring out exactly what we're buying. One of these
> days we'll have more disclosure and much more transparency...maybe.
>
> Here's a pretty good gathering place for folks that like to play with oil
> and filters. http://theoildrop.server101.com/cgi/ultimatebb.cgi It's not
> without it's warts, and it's sometimes not very scientific, but it's more
> informative than searching the Fram website... :)
>
> Andy
>>
I got on that site and read where a guy finds that the Fram filter stands up
to cold starts at 40 below zero. I wonder what the micron rating really is on
one of those?
The cold oil problem is the most difficult part of filter design. The steel
perf tube in the center of the element is strong enough to resist anything an
oil pump can generate, so should a high flow situation develop and collapse the
media around the tube, the filter must bypass to prevent the pump drive from
shearing off, or blowing the can off of the adapter. In the Michigan
situation, the little filter that doesn't (filter much) is the winner, because it
develops little flow resistance in cold oil.
Here is a case where the old Ford system of bypassing inside the engine makes
sense. Like my old Ford tractor, some oil gets filtered all of the time. In
the cold there is little oil being filtered, because the bypass valve is open
(and probably the pressure relief valve in the pump also) and any oil going to
the bearings is just not filtered until some oil temp is developed. It all
works fine. And like the man says, the Fram comes off for the warm weather. What
month is that in Michigan?
I forgot to mention that with all of the acquisitions over the last 10 years
have caused situations where competing manufacturers are now the same people.
Now just one division of that parent Co. makes both competing brands on the
same line to the same spec. where there may have been two specs before. Do you
think they now make both to the more expensive spec? How much cheaper should
one be over the other if they are identical?
Some filter manufacturers do not make the filtering media for their filters.
That makes sense. Filtration media is a complex product and most manufacturers
spec the media. I have here somewhere a sample of stainless woven media that
is so fine that it looks like a piece of sheet metal. Electron beam welded
edges. I should have thrown it out years ago, but it is too neat. If I find it I
will post a picture.
Lynn E. Hanover
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