I was wondering what type of filters you guys are running on the M.B.'s. Correct me if I am wrong but on my 85 300 SD the fuel is sucked rather then pumped to the IP and I would think fiters are designed to be either pumped thru or sucked thru. The reason I ask is that if I'm running my daily commute of 50 miles one way to work I probably can get 3,000 miles on a filter FF 760 from A.Z. but if i run on a long trip 700 miles one way I am lucky if I can get a round trip 1400 miles without changing 2 filters along the way. I am thinking that the constant sucking instead of pushing of WVO is causing the filter to partially collapse inside and restricting fuel to IP. I do have a valve at bottom of filter that I could drain to see if there is any water or dirt collected there but have not done that yet as I just change them when the car starves for fuel but do not like to change filters every 700 miles. I am centrifuging the oil so I think it is about as clean as you are gonna get it. Possibly the WVO has water in it that the fuge is not getting and the water is making the filter swell up and restrict fuel. I am just asking because I was talking to a guy near me that is running a gulf TDI on the WVO and he said he never had to change a filter because he had to only did it as a P.M. measure at about 3,000 miles but I'm thinking the V.W.'s have a pump to push the WVO and are differant then the M.B.'s. Any way what type of filters do you guys get good results on the M.B.'s?
My understanding is a filter should be under pressure - either fuel or oil. The largest surface area of a fillter is on the outside surface and is there to collect the contanimants. The manufacturers of oil filters have placed the input ports for the unfiltered fluid to flow to the outside so it must past through and toward the center section where it exits and on it way to be used. There are posts on this forum describing the possible breakdown of the filter material under suction. Might want to do a search. I have plumbed the VO through a seperate VO (heated by coolant water, $114 with a VW fuel filter and under pressure). The filter lasts for atleast 10K miles. The last VO filter that was changed in my '80 MB 300D looked brand new when it was inspected.
From Second Chance Garage web site:
How Oil Filters Work
Oil does a number of important things in an engine. It helps cool the engine by transferring heat; seals the gap between piston rings and cylinder walls; absorbs contaminants; and suspends soot particles that are the residue of combustion. Contaminants can be organic such as fungus and bacteria from the air. Inorganic particles can be a host of things, including dust that is sucked into the engine during running.
If left by itself for very long the oil would become saturated with the byproducts of combustion. It would carry minute, harsh particles that would wear the oil pump's machined components as well as the bearing surfaces in the engine. It always has done so, but in early engines the oil was changed so often (due to burning and poor oil quality) that no filtration was required. Later on some manufacturers put mesh screens in the oil path to grab bigger particles but this was not very effective.
The first oil filters were introduced in the early 1920s (Ernest Sweetland invented it and named if "Purolator," meaning "pure oil later.") Filters of many designs were offered as optional and aftermarket equipment for decades, but they didn't start showing up as standard equipment until the 1950s. These devices solved the contamination problem and allowed [relatively] extended periods of service for each oil change. By the mid 1960s, oil chemistry and filter technology was advanced enough to allow 4000+ mile change intervals. The original canister-type oil filter was quickly replaced by "spin-on" filters, except in a number of British sports cars that suffered from a lack of development funding. The spin-on filter is universally used today.
Today's engines run so cleanly that 10,000-mile oil change intervals are considered normal, but the job of the filter hasn't changed. It has to do its job well or the engine can suffer major damage. Here's how it works:
The outside of the filter is a metal can with a sealing gasket that allows it to be tightly held against the engine's mating surface. The base plate of the can holds the gasket and is perforated with holes around the area just inside the gasket. A central hole is threaded to mate with the oil filter assembly on the engine block. Inside the can is the filter material, most frequently made from synthetic fiber. The engine's oil pump moves the oil directly to the filter, where it enters from the holes in the perimeter of the base plate.
The dirty oil is passed (pushed under pressure) through the filter media and back through the central hole, where it re-enters the engine. Typically, filters have two media types: primary and secondary. The primary media can stop particles as small as 25-30 microns (human hair is 65-70 microns in size) and the secondary media can stop particles as small as 5-10 microns. "Full flow" filters only utilize primary media.
Thanks for the great explanation on filters. I think what I have to make sure is that my VO is entertering on the outside of filter and exiting from middle if it is not I could just reverse entry + exit lines and see how it works under those circumstances. I do not think I have a bypass valve on my fuel filter and I would not want one as then you would be letting dirty fuel to your injectors clogging them up may be that is why the guy with the V.W. told me he never had to change a filter because of fuel starvation maybe he is letting dirty fuel go thru if he has a bypass on his filter.I will look closer into this and probably reverse entry + exit ports and see if it makes a differance.
You picked up on the major point of the relief valve in the post about "filters". The folks who use "oil filters" to filter VO or D2 are asking for trouble by allowing junk to re-enter the IP. When choosing a VO filter, check very carefully the type of filter that is offered.
I am using a fuel filter it is FF760 with a drain on bottom my thought is that the VO could be going thru it the wrong way from the outside in instead of from inside out I will closely inspect how the the VO travels thru it next time I change one and reverse the inlet and outlet hoses if the travel is wrong or I might even reverse them to see if I get more miles before a clog. Right now I can get 3,000 miles on shorter 50 mile runs but if I go on a long haul like 700 miles straight I have to change the filter usually ounce or twice during the 1400 mile trip of steady running.
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