So, this was the previous arrangement for the engine breather hose… a 90-degree AN swivel fitting plus a 90-degree hose end:
I was driven to use this setup – which let's face it, was overcomplicated at best – by the limited options for hose routing that are available when you have an angled oil filter adapter, as my engine does. There's practically no good way to point the hose fitting that doesn't cause either the fitting or the hose to hit something else. But then I had a brain wave and thought of a much simpler solution, so I tore out the existing hose and engine fitting:
This is the new arrangement I came up with. The fitting on the engine is now a 45-degree brass hose barb, pointed towards the left side of the engine as well as somewhat forward. This allows the hose to clear the engine mount heading forward, whereupon it takes a medium-sharpish bend and turns 180 degrees back towards and air/oil separator. It does come close to the baffles and the oil cooler plumbing, but there's plenty of room for things to move around without rubbing together.
The hose is affixed to an engine mount tube with a pair of adel clamps, the purpose of which are to pull it down and keep it from rubbing on the inside of the top cowl, which is its natural tendency due to the angles involved. Although it seems at first glance like there isn't enough slack in the hose to accommodate movement of the engine, in actuality there's at least a foot of hose there, with a pretty good loop in it. This MIL-6000 hose is also fairly springy, and you can "boing" it back and forth an inch or two with your fingers. Compared to the fuel hose on the bottom of the engine, there's actually more slack in the new breather hose.
Here's another view, looking across from the right side of the engine. The engine mount and oil separator do not move relative to one another, so the short length of hose between the engine mount and firewall doesn't require any slack in it.
I have now re-engineered every piece of the breather system at least twice! I think it's truly all finished now. Here's hoping, anyway.