Gunked up Breather

[KyleTownsend]

Just thought I would tell you guys about a recent maintenance adventure.

My rear engine only has a couple of hundred hours on it, but it has been blowing oil pretty bad. And I don't mean from any particular source, I mean from every source - between the crankcase halves, out the pushrod seals, out the rocker gaskets, etc. Actual oil consumption wasn't bad. It doesn't take much oil to make a mess!

When I noticed that I was actually getting streamers on TOP of the cowling out the oil filler door, I figured the only place that could be coming from is the oil filler tube. Since the cap seemed to be sealing fine, this pointed towards excessive crank-case pressure.

I downloaded a Continental service bulliten on how to test for this from the CPA web site (MB89-9). Basically, you just hook an old airspeed indicator up to the dipstick tube with a length of hose (being sure to seal everything well). At full throttle, you shouldn't register over 90 MPH. If you do, you should disconnect the breather system. If it still registers over 90, then you've got cylinder problems. If not, then you've got breather problems.

Well, we fired her up and let the oil come up to temperature. Then I started easing the throttle in. By the time it hit the stops, I was through 180 MPH and still climbing as the turbo spooled up. I eased up before I blew my airspeed indicator apart.

We disconnected the breather system and tried again. This time, 85 MPH (whew).

We removed the breather components and found them to be really gunked up. I would estimate that about 1/3 of the volume of the hard-lines and hoses was displaced by a greasy milky-white substance stuck to the walls of the tubing. The air/oil seperator was full of this gunk, and seemed almost totally obstructed.

We cleaned and flushed all of the components and repeated the test. This brought us back down to the reasonable range.

Haven't flight tested yet to see what this does for my oil problem, but thought I would pass this along.

Kyle

[DHatfield]

Kyle,

I went through the exact same process last year with the same results. In my plane at least, the oil/air separator and most of the breather system is directly in the path of the cold air blasting in through the scoop.

I insulated the entire breather and the oil/air sep with high quality pipe insulation. I think this helps keep the oil from congealing in the system and plugging it up. Since I've been careful about the insulation, I haven't had the system plug up nearly as bad. I still remove and clean all the breather plumbing at each annual.

David

[Skymaster337B]

How did you clean the air/oil separator?