...........So the moral of the story is that the best thing to do for filtering is to make an efficient filter arrangement. If you insist on having restrictive filtering yet really feel the need to filter ever last drop of oil at any cost... then blocking the bypass is the way to go. Personally I'd rather leave it alone and set it up where it doesn't have to do anything..............but I'm tired (and been playing with timing covers too much lately)
Just like many discussions here, there is no one-size-fits-all answer as first the conditions of use need to be defined. I do agree with Earl, leave the bypass valve alone.
Depending on the oil pressure, what the use will be - RPM range especially upper limits, HP and boost developed, weather temp range and many other variables can help determine what oil filter will work best for a given application.
Since I do have lots of experience [and mis-experience
] with race applications, including other makes, not just Buicks, and would like to address that area first.
I doubt that most street engines do not see over 7000 RPM, high boost and HP very often and have an engine costing in excess of $20K, so I will start here.
We MUST have sufficient, un-interupeted oil flow at all times. Most filters will not handle this properly because of the filter media. It is usually too "fine" [8-15 microns] to pass the volume of oil needed.
At high oil pressure like at cold start, the oil will be forced through at the weakest areas and the result is "tracking". So say they claim 400 sq" of filter area, how much of this is actually used? Usually these filters also have a bypass internally to compensate for this issue.
The race filters from Wix and Fram address this issue, but still may have an internal bypass valve, but a higher micron number. The K&N and Mobile I have great specs, but do not flow well for performance use. This is not just an opinion as I have opened MANY race filters and seen distorted and clogged filter media.
The best filter I have found and do use in the race application is the stainless steel mesh in a 40-45 micron which does NOT need or use a bypass as they do not "channel" or clog. My engine gained 5-10 PSI oil pressure over the entire RPM range.
To continue along the lines of what Earl posted, if you have the right oil and filter for your application, you do not need to worry about the small amount and time oil is bypassed.
For a street application, the very small micron media filter probably does more harm than good, since the very small particles do no harm.
Good oil FLOW is also needed to help cool the internal engine parts. About 30-40 percent of oil cooling is done be the oil, the rest by water/coolant.
