John to answer your question, in the higher rpm situations the oil pump can pump under pressure the oil volume from the pan faster than gravity can return the oil to the pan. Our system and virtually every auto engine made has a gravity return, unless it is using a dry sump setup, which I will not go into here. Since the size of these oil return holes and gravity are responsible for the oil returning to the pan, it is important that we don't run into the potential of pumping a majority of our oil into the heads leaving too little in the pan, which could "slosh" to one side and uncover the pickup tube, causing air to be sucked into the oil system, which is the type of starving I am talking about.
I am running the stock oil system with oil cooler and filter in stock locations, so my oil pressure volume only needs to be what a new pump is stock on a new engine per Chevy. Mark Jones is running longer lines and remote setup and I agree this can/will cause some drop in the system pressure, delay in volume circulation, so it is appropriate for his system, and anyone like it (Mark L, & Bill Clapp) to do the same with in reason. Just remember that anything beyond stock pressures is probably excessive, and is also requiring more internal horsepower to generate, leaving a little bit less for the prop. Multi-viscosity oils are rated by the detergent additives that allow them to thicken and thin based on the outside ambient temp, and their temperature of operation. Serge, you probably saw numbers changed into the metric system, we here would see them posted on literature in F. The first number before the "W" is the winter rating, oil's ability to thin, and the second is the summer rating, and ability to thicken, or withstand high temperature before breakdown. The manufacturers do not add the "S" because it would be redundant. Doug and anyone who believes that running straight weight oils is just as good as multi-viscosity oils, just look at how long your engines last presently compared to the late 60's early 70's. This is pre-dominantly due to 2 things: oil technology, and internal temperature, which both work together to control wear. Filter technology also contributes here. Harley engines for years failed after very short times as compared to the Japanese motorcycle engines which were modified to take advantage of modern oils and technology. Not until this latest emergence of the Harley Evolution series of engines did Harley enter the world of truly modern engine design. The use of 20W50 oil in any engine that doesn't match the temp of the application for continued use, not just startup temp is foolhardy and an act of ignorance to what 50 years of development have accomplished. I do not trust "independent" testing in a lot of cases because typically the scope of the test is too narrow to be of much value, since it will only apply to a limited case/application. Assembly lubes are thick because of the need to maintain lubrication inside the engine in the case that the new oil system doesn't prime initially, or there is a delay in the oil pressure coming. All my assembly manuals have you run the engine for a short time, drop the oil out, change the filter to remove that assembly lube to prevent engine clogging, and then refill and run the engine for approx 50 miles or 10 hours of use and change again. This gets the additional metal out that gets shaved off parts as they seat themselves, hopefully not much. We are still running auto engines, and just like our previous discussion on oils, need to run what is appropriate for an auto engine, not aviation oils. Aviation oils are designed to both handle the particulars of those engines as well as deal with the much greater internal clearances that those engines have. Mark Jones' post shows the breakdown of the design of the oil he is using, and a review of the chart shows that his 15W40 has the ability to handle -33F temps, the 10W30 will go down to -40F. Thank you for that post Mark. This is what I was trying to illustrate. This looks like a very good "designer" oil for use since it covers a very broad range of oil temps and use, and does include that it is designed for both gasoline and diesel engines. The detergents in it for use with diesel engines should also help with the lead of 100LL that it will be exposed to also. Thanks again Mark. This will be my oil of choice as well after break-in. Colin crain...@cfl.rr.com http://kr-builder.org/Colin/index.html KR2(td) N96TA Sanford, FL Apex Lending, Inc. 407-323-6960 (p) 407-557-3260 (f) crai...@apexlending.com
