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Crankcase vent

Scott Hersha

Well Known Member
Friend
Just wondering if anyone has tried one of these, and if so, what were your results?


I currently have the ASA vacuum vent system on my RV6, O-360. I noticed some oil on the floor after flying yesterday and after investigating I found it was coming from the relief drain tube in that vac system. That means the check valve was not allowing vent air to come through and then venting through the small relief valve and hose. My first thought was it must be coked up, but upon further inspection, I found the check valve was actually stuck shut. There was very little coking as I’ve always found over the 2+ years I’ve been running with it. It wasn’t the check valve that came with the system from ASA, it was the more robust “better” check valve from AC Delco that I installed about a year ago (the original was still working, but after reading stuff here I was not sure I should trust it). I’ve decided to dump the whole system and go to the standard vent line dripping on the exhaust pipe unless there’s a better solution.

I’m just curious if anyone has experience with the above mentioned vent can. Spruce also sells it for a bit more.

Of course now I have to come up with some sort of plug/cover to close the hole I drilled in my tailpipe…..
 
Just wondering if anyone has tried one of these, and if so, what were your results?


I currently have the ASA vacuum vent system on my RV6, O-360. I noticed some oil on the floor after flying yesterday and after investigating I found it was coming from the relief drain tube in that vac system. That means the check valve was not allowing vent air to come through and then venting through the small relief valve and hose. My first thought was it must be coked up, but upon further inspection, I found the check valve was actually stuck shut. There was very little coking as I’ve always found over the 2+ years I’ve been running with it. It wasn’t the check valve that came with the system from ASA, it was the more robust “better” check valve from AC Delco that I installed about a year ago (the original was still working, but after reading stuff here I was not sure I should trust it). I’ve decided to dump the whole system and go to the standard vent line dripping on the exhaust pipe unless there’s a better solution.

I’m just curious if anyone has experience with the above mentioned vent can. Spruce also sells it for a bit more.

Of course now I have to come up with some sort of plug/cover to close the hole I drilled in my tailpipe…..
I've had great service from my ASA setup, 10 years and 1997 hours on it right now, and I just replaced the checkvalve for the first time at this past annual. I do get a fair bit of coking in the adapter between the check valve and the exhaust pipe and clean that out on every oil change.
 
I currently have the ASA vacuum vent system on my RV6, O-360. I noticed some oil on the floor after flying yesterday and after investigating I found it was coming from the relief drain tube in that vac system. That means the check valve was not allowing vent air to come through and then venting through the small relief valve and hose. My first thought was it must be coked up, but upon further inspection, I found the check valve was actually stuck shut. There was very little coking as I’ve always found over the 2+ years I’ve been running with it. It wasn’t the check valve that came with the system from ASA, it was the more robust “better” check valve from AC Delco that I installed about a year ago (the original was still working, but after reading stuff here I was not sure I should trust it). I’ve decided to dump the whole system and go to the standard vent line dripping on the exhaust pipe unless there’s a better solution.

Just one guy's data point... I have the same ASA oil separator, but I have its outlet terminated in the traditional way with a tube that ends just above the exhaust, i.e. no vacuum valve. So far I've been happy with this setup, great oil consumption rates and not a lot of oil on the belly. If you're going to weld up the hole in your exhaust anyway, you might consider keeping your already-installed oil separator and seeing how a similar setup works for you.

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Just one guy's data point... I have the same ASA oil separator, but I have its outlet terminated in the traditional way with a tube that ends just above the exhaust, i.e. no vacuum valve. So far I've been happy with this setup, great oil consumption rates and not a lot of oil on the belly. If you're going to weld up the hole in your exhaust anyway, you might consider keeping your already-installed oil separator and seeing how a similar setup works for you.

View attachment 112048 View attachment 112050
I don’t have an oil separator, just the vac system. I clean out the tube every oil change (25 hours), but have very little coking. I might just try the separator as you suggest, draining the residue onto a tailpipe.
 
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