Routing of canister oil lines ????

I would say by far the most common setup is oil ENTERS into the main housing, flows through the filter media, and then exits into the hollow center post, and then out the bottom.

Typically, there is a small hole in the center post near the top that serves as a restrictor to prevent too much oil from passing through the by-pass filter setup, and dropping engine oil pressure. Also, this exit port near the TOP of the center post allows air trapped in the filter housing to exit. If it were to be plumbed backwards, fed at the top, and having the oil exit lower down on the cannister side, you would never get much filtration, as you'd have a big air bubble trapped around most of the filter.

Take a close look at the unit you have, and note where the ports are, and consider how air would vent, and you may be able to figure out what orientation makes sense!

I have a few tractors and machines around with these cannister filters... I'll take a look at how they're plumbed, and post back.

I checked my collection of old stuff today, and here's the results:

9N Ford tractor... inlet line to fitting on side of cannister, outlet line on bottom of cannister, beneath, and fed from, center post.

1951 8N Ford tractor... inlet line to fitting on side of cannister, outlet line on bottom of cannister, beneath, and fed from, center post.

1952 Ford truck, 239 flathead V-8... inlet line to fitting on side of cannister, outlet line on bottom of cannister, beneath, and fed from, center post. There are NEAT decals on this one, gold background with black letters, indicating the inlet and outlet, and it is connected accordingly.

1953 GMC truck, 261 straight-6 engine... inlet line to fitting on side of cannister, outlet line on bottom of cannister, beneath, and fed from, center post.

Massey #92 combine, with Chrysler flathead 6-cylinder engine... inlet line to fitting on side of cannister, outlet line on bottom of cannister, beneath, and fed from, center post.