Oil Consumption and Breather Tube

[vic syracuse]

I had an RV-10 in for a panel upgrade today. As luck would have it we have to remove the top cowl to replace a couple of engine sensors. Since I usually test fly the completed projects I always give the engine compartment a good inspection. Lo and behold on this one the oil was pouring out of the dipstick tube and down between the cylinders. It doesn't show up very well in the picture, but the dipstick and dipstick tube were all covered in wet, hot oil. The bottom cowl was oil soaked. Well, I knew what the problem was as soon as I saw the Anti-Splat separator on the firewall. Sure enough, it was plumbed into the exhaust and all coked up. The owner says he inspected it and ran a wire through it a little over 30 hours ago.

I know I've said this before, but those of you who have these in this configuration need to be careful. Regardless of past experiences.

Here is a picture of what got my attention:


Vic

[PerfTech]

... Do you or can you take a photo of the vacuum valve installation so we can see the configuration? We are gathering information and have several tests going on in an effort to solve the coking problem on the RV-10s. This information would help us considerably. This issue is pretty much isolated to the 10s and this is the fourth one we have been made aware of. Thanks, Allan..

[RVG8tor]

Very curious about this. I had 40 hours since last inspection and still this is not occurring with my set up. RV8A, IO 360.

Seems this must be due to temperature differences in the exhaust systems. Watching to see what findings come about with all the work getting done on his issue.

Cheers

[vic syracuse]

Here is the picture. Looks like a stock installation.





Vic

[PerfTech]

Originally Posted by vic syracuse

I will take a picture of it, Allan.

Vic

Thank you Vic, we can't have to much information.

[scard]

Originally Posted by vic syracuse

Here is the picture. Looks like a stock installation.





Vic

I hope that wasn't a professional business that welded the bung/offshute onto the pipe. If it was, we need the name to avoid.

[Dbro172]

That particular installation also appears to be angled the wrong direction. Isn't the tube supposed to be angled forward relative to exhaust? Not sure what goes on behind that weld but this looks like the exhaust could actually be pressurizing. Anyone else see it like that?

[deek]

I've been following this thread but have been reluctant to post since this isn't on an RV - but it may help others who are trying to solve the coking issue. This exhaust has been on my O-320 LongEZ for 25+ years; more than 2,800 hours. Although I replace the valve at 500 hour intervals on general principle, I've never had to clean the mounting boss. When I first installed this system (designed and marketed by Wes Gardner in 1982) I confirmed the exhaust created a slight vacuum at RPM>1500. The boss is "squished" inside the header and is cut at reverse bias to help extract the crankcase vent. Oil consumption did not increase with the system and has remained ~12hrs/qt through several overhauls.

[CharlieWaffles]

Feel, what kind of engine is that? The only RV models reporting the problem are the 10am that use the io-540. The other models with smaller engines don't have the coking issue.

[C-FAH Q]

This is not a 540 only issue. I have a IO-360C1E6 and mine coked over in less than 50 hours. I had oil leaks everywhere when it plugged up. I like the idea/ pricipal of the mod, but don't feel it's worth the trouble I went through. That's just my opinion. If you have the mod installed on any engine, I suggest checking it frequently. Cleaning oil leaks from an engine is a pita.