1939 D2 3J Oil Filter

NAPA 1165 or Wix 51165 are the disposable bypass type filters.
Full flow are NAPA 1161 and Wix 51161

Sorry, I can't quite understand how it all came out of there. Any chance of a picture with it all laid out in order including the bolt down through it?

This is where I'm having trouble the 1165 an the 1161 are both to long of a filter, the filter I pulled out is only 4" tall...the filter housing is 7" tall on both the removable top piece and the bottom piece that is attached to the cat itself...I have attached a couple pictures of how it all comes out

Is this an using Cat or a museum Cat? If it's an using Cat, I would convert it over to the newer full-flow filter. It's easier and cheaper to service. Some Cat salvage yard will have the pieces.

My D2 5J was converted long ago, before I got it. I've had it for over 40 years, so the conversion sure didn't hurt the longevity of the engine!

That is the early bypass filter system. My book doesn't go back that far.

JDP,
I have one of those filters on an early D2 3J. I have the current CAT part number of the replaceable filter element that goes inside the brass washable one. I won't be able to supply that number until late Monday, but I do have the information.

That early bypass design is a bit of an odd duck; I had a devil of a time taking mine apart just looking at the parts book to figure it out. With the two hooks that go over the "ears" of the mating part, it was not real obvious how it was put together. That and the "rock hard" o-rings between the mating parts made dis-assembly fun.

I recall seeing that style housing in my book as a field modification to the early filter housing. It also could have been used as factory install for a short time, I don't remember that part exactly.

According to my 1955 book what you have there is the field Installation filter group for machines 3J1-3J2883,
part # for the filter Element in the top section is 5B8934,

the 1938 parts book shows # 5B96 Filter and Purolator # 20309X for the original filter .

shovel man.

Shovel man is correct, that's a field installation auxilliary filter unit that mounts on top of the regular two screen element lower housing. Current upper element is a Cat #1R0727 or WiX #51169 or Baldwin #PT61-HD element.

Replaces the original #5B8934 and #8B5935 filters.

This is still a by-pass system. The hex nut does not imply a full flow filter as the later slotted head hex (most of them) do. Appears it can be converted to full flow but will take several new parts besides the later conversion kit to get it accomplished. Probably easier to just change out the whole thing for a later full flow unit.