Quote:
Originally Posted by jcgreatoil
This is Jim, the Amsoil Rep again. The restrictor should DEFINITELY be removed because the new filter head does not have it and it does not open fully until your oil reaches 180 degrees. The oil will never reach 180 degrees in a SMB because it is so far away from the engine acting like an oil cooler. Your system will operate much more efficiently without it.
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I would like to start with a warning that for some unknown period of time I have not been getting any circulation through my bypass system. You should check yours if you have not corrected the hose routing yet. When I first became aware of these topics through the SMB email and then this forum I verified my hose arrangement. At that time I started up the engine and ran it for 10 minutes or so until the temp gauge was heading up to normal op. I checked and both filters were cold as were the hoses. I mentioned that in a early posting. On Dec 31 I returned from a 5 day camping trip and after running the engine most of that day and immediately after pulling in the driveway both filters were barely warm. I decided then that I needed to pull the system and correct the hose arrangement. I have 4500 miles on the filters and oil and initially was going to take the SMB recommendation to take care of it at the next filter change (15K). I know my previous filters ran hot because I have a sampling petcock on the filter head and had to be careful taking samples. A barely warm filter can only mean flow was severely restricted. I removed the filter head so I could consider removing the restrictor valve. I did learn something I didn't know before. Normally oil enters the filter from the outer ports and is pushed to the center. The spin-on thread port is the oil return. My installation instruction is for the BMK 16. The AMSOil site no longer lists that model but when you pull up the instruction for a BMK(?)-26 model you get the same instructions. Here are some observations that anyone is welcome to comment on.
1. The larger bypass filter is closest to the inlet and outlet port. There is NO temperature regulation mechanism in the filter head. The bypass filter is subject to full flow / pressure at all times. The filter itself would have to contain the temperature based flow control if it exists at all.
2. The full flow filter is farthest from the inlet / outlet. There is a spring loaded, tapered end, cylindrical restrictor valve in the bore on the inlet to the filter. The bore diameter is about 5/8 inch. The valve body has a 5/16 hole drilled through it. Oil pressure will push the valve open. At some point in its travel it opens the inlet side to full flow. To me this would cause the valve to seek and reach an equilibrium based on pressure not temperature. Hotter oil might increase the flow through the center bore but I'm not sure how this would effect valve position and the throttling effect. Intuitively I would think colder oil would hold it open farther.
3. With a reverse supply line connection the restrictor valve is non functional. It will never open as oil pressure is holding it shut. You are only getting 25% flow at all times through the full flow filter. This is based on the fact that the 5/16 hole through the center of the valve is 25% of the overall area of the outer diameter.
4. I do not understand why my filters never warmed up even after 150 miles unless there is some type of backflow prevented in the oil filter or why my other filter installations seemed to run normally (hot). The restrictor valve has no direct effect on the bypass filter.
5. I left the restrictor valve out when I reassembled it. I verified my SMB provided block adapter did shoot oil out of the return hose. I swapped my connections at the filter block. I installed new filters (AO-26 until I can get the new recommended one). The filters now start warming up immediately. I drove 10 miles and now you can not hold you hand against either of them as they are so hot. To me they seem to warm up equally.
6. I had to add 2 quarts of new oil but I plan to get an oil analysis before I put any more miles on it and it gets anymore normal filtering. I have two previous analyses to compare against.
7. I wonder if the SMB recommendation and oil testing, parameter testing was based on the newer filter head with out the restrictor.
8. CHECK YOUR FILTERS FOR FLOW if you have the reverse connection and older filter head.