On a quest for the elusive "Dry AeroVee"

[Tnhelm]

I have been dealing with oil leak since day one. Locations have been valve covers, sump plate and engine case seam. The valve cover issue has been somewhat reduced with either additional washers under the valve cover bolts or shorter bolts which were bottoming before sufficient pressure could be placed on the covers. The sump plate issue has been reduced by replacing the mount studs with bolts but I intend to replace those with longer studs. Most leakage seems to be coming from the lower aft case bolt where the intake support is fastened. I am trying several minor fixes to remedy that short of eventually overhauling the engine to reseal the case. I did install the breather tank and admit without that conditions would be much worse. It seems to collect 2 to 3 once’s of oil an hour of cruise power operation. Because my tank mount is somewhat low compared to the engine sump, I did not install a return line to the engine sump. I do have a quick drain valve on the bottom of the tank. Ironically, my leakage has not caused any oil saturation in the engine compartment, just below the belly.
One interesting issue I have is that the aero ejector carb gets saturated with oil just sitting in the hanger from the dripping case.
Tom.
OneX 0137

[Bryan Cotton]

Could this installation be pulling oil out due to vacuum? You may need to click the picture to expand and see the relevant part.

breather exit.jpg (93.96 KiB) Viewed 3056 times

I've since shortened the tube and the bottom is aluminum, but it's similar.

[Onex107]

Brian, the "catch can" really works. My home made one was a pint sized "Ball" jar, calibrated on the side in oz's. The standard top has a two pc. ring and center. I plumbed the center with plastic pipe fitting with a tube to the bottom of the jar. Drilled vent holes around the center fitting, tied a stainless chore ball under the lid to filter the vent holes, and mounted it on the fire wall with a large hose clamp. By loosening the hose clamp, I could loosen the jar ring and remove the jar. I recorded the volume of blow by in oz's. Compared to my Cessna O-200, the Aerovee is more like a car with oil consumption. The most oil blow by I measured was 10 - 12 oz in a 25 hr. oil change at 350 hobbs hrs. Whereas the O-200 "used a normal" quart in 10. The belly still gets dirty but it doesn't drip.

[Bryan Cotton]

Brian, the "catch can" really works. My home made one was a pint sized "Ball" jar, calibrated on the side in oz's. The standard top has a two pc. ring and center. I plumbed the center with plastic pipe fitting with a tube to the bottom of the jar. Drilled vent holes around the center fitting, tied a stainless chore ball under the lid to filter the vent holes, and mounted it on the fire wall with a large hose clamp. By loosening the hose clamp, I could loosen the jar ring and remove the jar. I recorded the volume of blow by in oz's. Compared to my Cessna O-200, the Aerovee is more like a car with oil consumption. The most oil blow by I measured was 10 - 12 oz in a 25 hr. oil change at 350 hobbs hrs. Whereas the O-200 "used a normal" quart in 10. The belly still gets dirty but it doesn't drip.

Cool, thanks!

[sonex892.]

Hi Bryan.
After a recent rebuild of my jabiru I was getting a bit of blowby before the rings had bed in. Although nowhere near the quantity of oil you appear to have, I had an annoying bit of oil spitting on the underside of the fuse out the breather tube. I have been using a catch bottle for 12 years but it was letting some oil past. I designed a new catch bottle with the idea to spin the oily blowby airflow. The inlet tube from motor is the center one in the top. The bottom is just a plug to remove to drain it. Been using it a few months now, oil on the belly stopped immediately.
Steve

[Bryan Cotton]

Steve,
Looks great, thanks for the response. Is it made of fiberglass? Hard to tell from the picture.

[sonex892.]

Steve,
Looks great, thanks for the response. Is it made of fiberglass? Hard to tell from the picture.

Yeah Bryan, the container is made from glass and epoxy resin. The end caps and tubes glued in with epoxy and flocking fibre. Tube and baffle section is welded aluminium, but could possibly be all glued together with epoxy and flock if welding is not an option.
Steve

[daleandee]

I purchased one of these for my Corvair but haven't needed it yet:

https://www.aircraftspruce.com/catalog/ ... eather.php

[Bryan Cotton]

I purchased one of these for my Corvair but haven't needed it yet:

https://www.aircraftspruce.com/catalog/ ... eather.php

Looks nice. I bought one of these and will try it out.
https://www.amazon.com/dp/B089VX5JB5

I'm thinking I'll chuck the air filter thing. It comes with a plug in that spot and the air filter is separate. Instead of the drain valve, I think I'll route that to the valve cover.

[DCASonex]

Bryan,
That filter /catch can from Amazon looks neat. Just ordered one for my CAMit 3300. I get very little oil on belly with what I have, but this looks like it might be an improvement. Thanks

David A.