Saw a ? on an other site , reminded me that I saw these at the Cummins dealer , asked parts counter guy , but I do not think he knew .
Is there one of these that should fit on the 5.9 spin on ?

 

A bypass filter is desinged to filter all the oil that goes thru it the one that I was getting has a orifice in it about 1/8 inch in diameter.You plumb them in to a oil port like were your gauge is and return the oil to the crankcase they say in about 15 min of running you will filter all the oil they are also a much finer filter than the normal full flow.Check out this link for some good pics on how some one did it.

http://www.mark74.com/ram_modifications.htm

 

I may have not made my point well enough , Fleetguard makes bypass filters , that spin on in place of the stock filter , so far I've been told that they only fit the large engines , I was asking if anyone had found one that fit the 5.9 ?
Thanks John

 

John, I wonder if you are confusing a bypass filter as wvo describes which filters to a higher degree than a main filter and a bypass filter where the filter itself bypasses unfiltered oil.
Our engines don't need a filter with a built in bypass as the pressure relief valve bypasses unfiltered oil.

 

wvoposered & Bill , I did not get a link the last time I checked , because I did not find a part # for my application , but on the Cummins / Feetguard web site under filtration , they is a number generations of by pass oil filters , the latest being branded venturi something , it is a spin on 2 stage bypass filter in one can , so far I have not see anything about it being available for the 5.9 .
I am familiar with by pass filter systems , I have a use , old Amsoil dual by pass that I got from a friend [ is suspect it is a different brand , but was told Amsoil by my friend ] , I would like to use some thing that takes up less space like the Fleetguard .

 

I have never seen one for the 5.9's. The 855,s and n-14's use them though. two stages of filteration, the bototm third of the filter being the bypass portion. these are BIG filters

 

I have seen those also I think Mercedes used that design on some of there diesel engines also.All engines should have them then they would last a lot longer.

 

These are very big filters and also 3 port. Oil comes from the pump into the main port where it splits into two streams inside the filter. One stream which carries about 90% of the flow goes to a full flow filter like we use, it's rated around 20-30 micron and from there the oil goes to the galleys of the engine for lubrication. The other stream (10%) heads to the by-pass section which is a very fine filter (2-5 micron); oil won't flow through it when the oil is cold. When the oil warms up and starts flowing through the very fine filter it is returned to the oil pan/sump. These fine filters need a high pressure differential and warm/low viscosity oil to function; when they are working they allow extended drain intervals and so forth. If you used a 2 micron filter as a full flow filter nothing would go through the filter (all oil would flow through the filter by-pass valve) until the engine oil was totally warmed up. The 5.9 would need a new filter mount with the proper ports to utilize a bypass filter. There are companies who sell separate bypass filters and they take oil off the 1/8 npt hole on top of the oil filter housing, route the oil through the bypass filter and dump it into the valve cover or oil fill cap.
hope this helps, cd