On a quest for the elusive "Dry AeroVee"

[Area 51%]

Since the oil comes up through the pushrods (1/8in hole) and drains back through the pushrod tubes (3/4in I.D. minus the 3/8 O.D. of the pushrod) I doubt there's ever oil deeper than the bottom of the tubes. The exception might be a tight uncoordinated turn. There are special windage pushrod tubes available for "just such an emergency" as Foghorn Leghorn would put it.

Some installations have return oil going to the valve covers to get it back to the sump.

Tell Marianne to add the extra nickel to my account.

[Bryan Cotton]

Here is my valve cover breather installed and safetied. It comes with an O-ring, and I'm thinking I'd be better off with a gasket. You can't sock down on the o-ring as it deforms.

As you can see I've recently got a safety wire fetish.

We have taken the next step in CNC machinery:


Sort of silly, but we made a breather (generator stand) block off plate on that router. Not silly from the point of the learning exercise.

The bolts for the original breather plate were a bit loose. I'll drill those for safety wire too.

[Bryan Cotton]

Here is my updated breather installation:

There are two things I like about it:
1) It is much more uphill than the prior installation.
2) It's away from the spinny parts that are slinging oil.

My silicone hose is not very oil resistant. It has both expanded a little bit and it seems to be sweating oil. I think somebody else on the forum had a similar issue and I'm open to hose suggestions.

Also, an updated CNC router video showing the fabrication of the generator stand block off plate:

[Bryan Cotton]

I did one pattern this AM, 0.3 on the hobbs. Cut short due to unforecast low clouds popping up. No oil out the breather - a bit early to call it a victory but I am hopeful.

[Bryan Cotton]

I've not found the elusive dry Aerovee yet. In fact I think something blew out on my last flight. Oil was really low and there was a massive amount of it on the belly. I knew something was up when there was oil on the rudder horns.

[XenosN42]

I'd check the oil cooler first.

BTW - I stopped using an oil cooler a couple of years back. Oil temperatures are still OK even in the summer. But, I admit, I don't fly when the temps are in the mid 80s or higher. The plane can handle the heat, I can't.

[Bryan Cotton]

I'd check the oil cooler first.

BTW - I stopped using an oil cooler a couple of years back. Oil temperatures are still OK even in the summer. But, I admit, I don't fly when the temps are in the mid 80s or higher. The plane can handle the heat, I can't.

I'll check it all! Definitely will check the oil cooler though.

[Bryan Cotton]

There was plenty of oil on the dipstick when in flight attitude, i.e. tail on sawhorse. The engine is reasonably dry. I mean it's not in danger of corroding or anything. We had a strong left crosswind landing on the last landing, so left wing down. That would put more oil in the left cover, potentially. If the cover was full I could see a lot pumping out.

I think I am going to revert to the stock breather setup, without my baffle. It is possible this is all self-inflicted from my own creativity. If anyone has drawings/pictures of catch cans or air-oil separators, I'd love to see them. A catch can would save some mess and let me quantify how much I'm losing through the breather.

I may try a breather in each valve cover if the stock setup doesn't work for me. If one is full of oil it should vent through the other side. What do you think?

[Panther16]

Is it possible you may have hi breather pressure due to poor ring seal?
Keith Rhode
Sonex 214KE 500 hrs
Panther 109kE 286 hrs

[Bryan Cotton]

Is it possible you may have hi breather pressure due to poor ring seal?
Keith Rhode
Sonex 214KE 500 hrs
Panther 109kE 286 hrs

Definitely possible. The engine has about 11.5 hours so far. Using the break in oil change intervals, it always looks pretty clean. I'm really happy with my static RPM and performance in general. I've not babied the engine as per the assembly manual. I've not done a compression check.