Posted by Jackson Reimund on Monday, January 21, 2002 at 9:40PM :
In Reply to: Re:Why??? posted by Matt Wilson on Monday, January 21, 2002 at 7:33PM :
Hi Matt,
Actually it is quite easy. With the full flow system all the oil has to pass through the filter on it's way to the cam and then on to the main crank bearings. The full flow filter has to allow the oil to flow through fairly freely even as it (hopefully) collects and fills with carbon and dirt particles. Remember as far as your bearings are concerned flow is the important factor not necessarily pressure. Hence the full flow filters are manufactured more open or porous allowing the finer particulates to pass through. The finer carbon and dirt particles just keep passing through your bearings and oil pump making more frequent oil changes absolutely necessary. Drive a real dusty road any length of time and your oil will collect much of it. Like a paper air filter becoming less efficient as it traps dirt. I can say a lot about oil bath air filters as a premium part of this process here but I'll save it for another time.
Also a designed full flow system should have an emergency by pass pressure valve so as to not starve the bearings of oil flow if the filter becomes stopped up. If you redesign your filter system an emergency bypass must be incorporated or you risk cam and bearing damage. Not to be overlooked.
In reality the percentage of oil passing through the bypass filter is far more than you think. The flow to the bearings is regulated and all the rest of the oil pressures on through the filter. This set up allows a filter that can trap the finer particles of carbon and dirt. It only takes a few minutes for all of the oil to be thoroughly cleaned. A toilet paper filter as you can see is so fine and layered it can trap the very finest particulates. It is so fine it will trap and clean water out of the oil. No drop in stock filter will do this.
To answer the question below about the toilet paper just swelling and turning to mush? Nope! Amazingly just the opposite occurs. No paper comes loose instead the roll shrinks slightly and firms up.
I'm like you. If I have it I'm driving and working it. 32 years on the M-37. I keep threatening to clean it up and paint it one of these years. Oh yea my other driver is the Harley. 24 years on that one and I keep it pretty.
The Best....Jackson
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