Lehman 120 Fuel Filters?

If the "stock" engine secondary fuel/water filters are 10 micron, does that indicate that the injectors and pump are going to be "happy" to see junk, 9 micron and smaller?
In that case, my primary (racor) should not be a 2 micron, but a 10 ( the engine filter will not see much junk) or 30 micron ( Racor will catch the BIG stuff and engine filters the rest)

Primary should be 10 Microns, the secondary( on the engine) 2 Microns.

Ed Tibbetts said:

If the "stock" engine secondary fuel/water filters are 10 micron, does that indicate that the injectors and pump are going to be "happy" to see junk, 9 micron and smaller?
In that case, my primary (racor) should not be a 2 micron, but a 10 ( the engine filter will not see much junk) or 30 micron ( Racor will catch the BIG stuff and engine filters the rest)

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ED, You are correct in saying your engines probably came from the factory with 10 micron filters. They did not, in most cases have any primary filteration and did, and still do very well. However injectors do not like trash or water so to save us problems in the future companys and people started putting a primary filter of 10 to 30 microns to get the big stuff and changed th secondary (engine) to the 2 micron.
You will find that watching where you get your fuel and changing you filters regular, you just won't have many problems. Having said all that clean fuel and clean oil are the life of a diesel engine.

Where can you get 2 micron filters that will fit the CAV filter housing that are on the side of the ford lehman. I am using NAPA 3166 and they are 10microns