You are mistaken if you think that today's oil filters are "full flow". They are STILL partial flow having an OIL FILTER by-pass either built in the filter it self or in the block. The filter CAN NOT flow all the oil to the motor especially when cold or when the filter is dirty. Under these conditions the OIL FILTER BY PASS (different than the OIL PUMP by pass) opens to let oil by the filter so the engine is not damaged from lack of lubrication. Dirty oil is better than no oil at all. Now once the oil comes up to operating temp and under MOST normal operating conditions, the filter is filtering MOST of the oil. But they are not truly "full flow" filters. Now there are some engines set up to also filter the oil that is by-passed from the main filter. They use a "main" filter AND a "by pass filter". In this case ALL the oil IS filtered. Mostly used on large truck and industrial engines. Don't believe me?? Try running a filter with out a by pass on an engine designed to have it in the filter. Then try running 20-50 oil on a nice cold morning. One of two things will happen. IF the filter holds it will usually blow the seal out from under it, or it will burst the filter, or it will blow the filter right off the motor. Seen it happen! Bruce Hevner _______________________________________________ Amc-list mailing list Amc-list@xxxxxxxxxxxx http://www.amc-list.com/mailman/listinfo/amc-list