I had originally planned to just give an update to my continued observations in connection with bypass oil filters and synthetic oil. Long time members will remember the original work that began in October of 1998 - my, my, could it possibly be that long ago. Well maybe they won't remember the actual work, but they will remember that I wrote about this subject back then. When the project first began, it did not include tests of synthetic oil. That became an object of the test beginning in February of 2000. The flood of e-mail I have received about these subjects has convinced me that a brief restatement of these tests could be useful. For those who want all the original work, they are in the archives. If you don't have an interest in this subject, just delete these posts. HOW IT STARTED In the summer of 1998, there was a thread on TWL that discussed bypass oil filters. At the time, I had never heard of such filters and didn't have a clue about how such filters worked. I had a conversation with a respected engine mechanic who told me that a fishing boat captain had installed such a filter and later removed it because it didn't work. At that point, CaptnWil made a mistake that he will not soon make again. Without verifying the story with the source - the fishing boat captain - CaptnWil reported the conversation. Gulf Coast Filters manufactured the bypass oil filter in question, and in due course, Charlie Sims, president of that corporation, called me on the phone to discuss the situation. His claims were shocking to me, and I asked for some real data to back them up. I told him that I was from an engineering background, and he should be careful what he sent since I would look at the data from an engineering point of view and report what I found - good or bad. I was surprised to find that none of the data I got was "sales literature." It consisted of engineering data from Shell Oil Company, The US Military, and such other technical sources. I learned that the North Carolina Ferry System used GCF bypass oil filters on all their ferries. Since the ferry maintenance headquarters was close by, I visited with its leader, asked questions, and observed the ferry installations. I phoned Charlie to tell him that I found all was in order in an engineering sense and that I would report my findings to TWL. He asked, if in addition to reporting what I had read and discussed with the ferry people, would I consider testing the filter itself. I accepted with the caution that I would report the results of the test - good or bad, and if they were bad, he might not like that. I declared that if that gave him a problem, we should just drop the whole issue right there. The equipment was at my door within a week and installed on AfterSail a week after that. WHAT A BYPASS OIL FILTER DOES The oil filter world for internal combustion engines is divided into two groups, Full Flow, and Bypass. It is intended that all the oil pumped by the oil pump pass through the Full Flow filter. The only time that isn't intended to do so is when the pressure drop across the full flow oil filter is too high. That condition is created at engine startup and when the filter gets clogged. The design of the full flow filter is based on the truth that dirty oil is better than no oil. That means that the filtering element must be carefully designed so that it takes out as much crud as possible, but still allow full oil flow at all times. Because of that design restriction, oil filter elements do not normally remove particles less than about 20 microns. Remember that it is intended that all the oil that gets to the engine goes through the full flow oil filter. The Bypass Oil Filter receives oil from the oil pump, filters it, and returns it to the crankcase - it bypasses the engine. At first blush, that seems a very stupid thing to do, but have faith, it will become very clear as we go along. Because none of the oil that leaves the bypass oil filter goes directly to the engine, but back to the crankcase, it has no restriction on how small a particle it can safely filter. If it gets clogged up, the system is right back where it started before installing the bypass oil filter - no catastrophic harm will come from this condition. The result of this is that the bypass oil filter can, and does, safely filter particles of sub-micron size. About 10% of the oil is normally directed through the bypass oil filter. WHAT ARE THE CLAIMS All of my tests were done on bypass oil filters produced by Gulf Coast Filters, but there are many different manufacturers of these filters. They all work on the same general principle, but most have different kinds of filter media. The claim for the bypass oil filter is that the better filtering will reduce the wear in the engine, allow extended oil drains, and increase engine life. It follows, if that is true, that there will be less cost to the owner, less used oil to dispose of, and an improved the environment. The sole purpose of CaptnWil's tests was to make an independent judgment for his own benefit about the validity of those claims. I share the results with you for what ever purpose you desire. I have nothing to sell and no financial interest in anything I report on to TWL. It is desirable to have good engineering data from other sources, but if they were true, I should be able to corroborate their findings. ABOUT THE TESTS It was decided that the tests would be in the form of taking oil samples on the engines involved and having independent laboratory analyses done on those samples. There will be more about the value of laboratory analysis a little later, but for now, just consider it to be one of the most valuable tools available to any engine owner. Over the course of time, seven engines were involved in these tests, and four continue to be part of this "work in progress." I owned, or have owned, all of the engines in this test series. There were five diesel engines and two gasoline engines involved. Of the remaining four, two are diesel. I was very fortunate to discover a portable oil analyzer (Lubri-Sensor) in the early stages of these tests. It was determined that the portable oil analyzer - POA as CaptnWil coined a name for it - produced very accurate results. In addition to laboratory analysis, it is the perfect instrument to conduct the tests on such a large number (to me) of engines at frequent intervals. There'll be more about the POA a little later, but it produces results at least as sensitive and useful as the formal laboratory analysis. The tests were made my CaptnWil alone, and all conclusions are his alone. The information that follows will be on the equipment and oil I used. Results from different bypass filters and different oils may vary. CaptnWil only offers data and opinions on products he has actually tested. That should not be taken to mean that there is any bias against other filters and/or oil. It just means I haven't tested them so I can offer no opinion about them. The oils in the tests were Shell Rotella T 15W-40, Mobil Delcac 1 5W-40 and Mobil 1 0W-30 synthetic oils. WHAT THE POA READINGS MEAN This little blurb will give you a feel for what the POA readings mean. The table will be included in each segment so you can keep score. The POA measures the difference in the electrical capacitance of a sample of used oil as compared to a sample of new oil of the same brand and specs. It reports its findings on a scale of 0 to 12. 0 (zero) is the value of new oil from a newly opened container. New oil is saved in an airtight container for future use. The readings increase as any contaminates are introduced into the oil. The meaning of the readings is different for petroleum based oils and full synthetic oils. It is undetermined for blends. It could be worked out for a blend, but would have to be done on an individual oil basis. Here's what the reading mean: POA READING ACTION REQUIRED Petroleum Full Based Synthetic 2.5 3.5 Change Bypass Element 3.6 5.0 Get Laboratory Analysis 4.6 8.0 Change Oil The difference in the readings for petroleum based oil and synthetic stock is because these oil stocks have different electrical characteristics. The action recommended at the different levels was determined by matching the readings with the recommendations of laboratory analysis on the same samples. All of the readings I have ever taken match directly with laboratory analysis. Next time, we'll detail some actual results. CaptnWil