Posted by Jackson Reimund on Tuesday, January 22, 2002 at 1:32AM :
In Reply to: Re:Why??? posted by RDavis on Monday, January 21, 2002 at 11:43PM :
My Spitfire I believe has perhaps the same full flow as you describe.
On the bypass system if your filter were clogged/stoped it would only mean that oil was not going through the filter. Oil would still be going through the cam and bearings. They have separate paths. Here is where the difference/confusion is between full flow and the bypass system. On the bypass the oil does not partially split off from the cam to the filter and then back to the bearings.
On the bypass system oil under pressure from the pump goes to the cam. Here splitting off at the cam excess oil under pump pressure goes to the filter and from there back to the oil sump in a continuous cycle. There are really two separate oil cycles using the same pump. As long as the motor is running sump oil is continually running through the filter and back to the sump at a fairly high volume.
As the bypass theory/system is supposed to work only the smaller amount of regulated oil that is needed by the motor is run through the bearings etc. and then washes down to the sump. The other and larger flow is continually running through the filter and back to the sump. The idea being that the oil in the sump is constantly being cleaned and when you shut off your motor the oil is clean and therefor not contaminated.
Working correctly more oil flows through the filter than through the bearings meaning a greater volume of oil is being filtered. Full flow may be better for some other motor types especially high rpm, overhead cams etc. but for the short train low rpm flathead the bypass system is simple and very efficient. When I put the Spitfire together I will use the bypass system.
I think I have run out of ways to explain it.
Regards, ... Jackson
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