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ASA Air/Oil Separator: Installed!

bill.hutchison

Well Known Member
For a lot of you this would be a trivial task, but for me, a newbie owner, this was pretty major.

I was able to install the Air/Oil Separator, use the braided line that came with the kit (because I had the right place on my case to return oil) and get the vacuum kit installed with the safety valve.

I'd had a few questions about the kit and how everything was supposed to go together. Allan has to be one of the most patient people on earth; walked me through all of my questions and helped me figure out how it was supposed to work.

I ended up keeping my existing breather tube and connecting it up....everything went together just fine.

Unfortunately, the rain rolled in as I was finishing up so I haven't had a chance to fly with it, but I'm looking forward to it.

Excellent service and support from ASA. I'll keep buying accessories as long as they keep making them. :)
 

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Bill,
Good Job!
Allen is really an asset to us RV guys for sure.
I have been using his products for years and really like the vent system.
Try to keep the vent hose from the engine to the separator running uphill, as vapor can condense in the hose and run back into the engine saving the "system" from processing it and less oil for coking in the exhaust. Also check the check valve for coking every annual or 100 hrs. I remove mine and clean it out with a round wire brush.
Best of Luck and thanks for posting your results. Especially with pictures!!
 
Bill,
Good Job!
Allen is really an asset to us RV guys for sure.
I have been using his products for years and really like the vent system.
Try to keep the vent hose from the engine to the separator running uphill, as vapor can condense in the hose and run back into the engine saving the "system" from processing it and less oil for coking in the exhaust. Also check the check valve for coking every annual or 100 hrs. I remove mine and clean it out with a round wire brush.
Best of Luck and thanks for posting your results. Especially with pictures!!

Thanks Bob - yeah, Allan was pretty emphatic about routing that hose down and then up. I'm actually thinking about getting a longer length of hose and running a longer route with a bigger loop, so to speak, but I'm going to wait a bit and see how that goes. It'll also be nice not having to clean the belly so often. And if the vac helps with the one or two weeps I've got, so be it.
 
Bill,
Good Job!
Allen is really an asset to us RV guys for sure.
I have been using his products for years and really like the vent system.
Try to keep the vent hose from the engine to the separator running uphill, as vapor can condense in the hose and run back into the engine saving the "system" from processing it and less oil for coking in the exhaust. Also check the check valve for coking every annual or 100 hrs. I remove mine and clean it out with a round wire brush.
Best of Luck and thanks for posting your results. Especially with pictures!!
+1 on the regular cleaning. That includes the tube from the valve to the exhaust pipe.
Question: are solvents okay to use on the valve (mineral spirits)?
 
routing that hose down and then up. I'm actually thinking about getting a longer length of hose and running a longer route with a bigger loop,

If you go down then up, you create a place for oil to collect (some oil will condense in that hose) in the lowest part of the hose, just like a P trap under your sink. When that happens, the crankcase has to build up pressure in order to force that oil uphill in the tube. You want to avoid pressure in the crankcase.

Larry
 
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Thanks Bob - yeah, Allan was pretty emphatic about routing that hose down and then up. I'm actually thinking about getting a longer length of hose and running a longer route with a bigger loop, so to speak, but I'm going to wait a bit and see how that goes. It'll also be nice not having to clean the belly so often. And if the vac helps with the one or two weeps I've got, so be it.

Bill,
Raising the separator can help too.....
Didn't hear about down and then up....seems it would hold oil then. Can't imagine it makes that much difference. But having the line run downhill to the separator can add to the amount of oil leaving the engine. Which is not helpful in the process. Allen learned these tips while trying to solve the coking issue among may different installations and is passing them on.
 
+1 on the regular cleaning. That includes the tube from the valve to the exhaust pipe.
Question: are solvents okay to use on the valve (mineral spirits)?

Allan said yeah, he suggested gasoline every once in a while.

If you go down then up, you create a place for oil to collect (some oil will condense in that hose) in the lowest part of the hose, just like a P trap under your sink. When that happens, the crankcase has to build up pressure in order to force that oil uphill in the tube. You want to avoid pressure in the crankcase.

Larry

I was curious about that because I had the same thought...I was expecting that maybe the vac portion of the system would reduce that. I am, obviously, totally unsure there.
 
Try to keep the vent hose from the engine to the separator running uphill, as vapor can condense in the hose and run back into the engine saving the "system" from processing it and less oil for coking in the exhaust.

It is advantageous to run the engine-to-separator hose uphill as much as possible, but the goal is definitely not condensation of vapor. Condensation anywhere in the system is undesirable.

At operating temperature, substances with high vapor pressures (here water and acids) are in vapor phase as they leave the engine case. We want them to stay in vapor phase (a gas) all the way to the system exit. To do so, keep temperature high in the breather outflow.

Substances with low vapor pressure (notably oil) leave the engine case as liquid aerosol droplets suspended in the flow. It is desirable for them to coalesce in the breather hose, form larger droplets, fall out of suspension, and run back to the breather port. Aerosol droplets which don't coalesce in the hose will hopefully do so in the canister. Droplets remaining airborne continue on to the system exit. If the system exit is an exhaust tap, the oil droplets can coke and form a plug.

Also check the check valve for coking every annual or 100 hrs.

We've seen a lot of variation here. Some have coked the exit tube shut with as little as 35 hours on the clock. I've gone as much as 140 in my own experiments, and now clean every 50, at oil change.

Start with inspecting frequently for deposit buildup (like 25 hour intervals) until the owner can establish a build rate for an particular installation. Expect an acceleration in deposit rate given operations which put more oil into the breather, or as engine wear results in more blowby.

The fast, positive method for cleanout is a drill bit sized a little less than the tube ID.

https://www.danhorton.net/Articles/Separator-or-Condenser.pdf
.
 

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Whatever it takes to run steadily uphill.

Ok. You've got me re-thinking and possibly over-thinking this now....

The first picture here is how it's routed now. As you can see, the crankcase breather points left, (relative to the pilot seat) so I have to go around the oil filter to get to the separator....length of the hose means there's a down-turn before it climbs uphill again, so the condensation P-trap issue may exist here.

Second photo is another routing idea I had. I still have to go around the filter - any sharper of a bend and it starts to kink the hose, which I think is bad. It also is too tight of a turn to NOT go around the filter or through the motor mount.

Doing it this way would allow me to shorten the hose and do more of an uphill route...is this better? Seems like it would be. It sort of rests against the firewall but I think I can twist things a bit to keep it off of the firewall.

Very new at this. Appreciate the help on such a 101-level issue.
 

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Go with photo #2. Do yourself a favor and insulate the hose while you have accessible.
 
Great article Dan

Hey Dan,

What a great article,
https://www.danhorton.net/Articles/Separator-or-Condenser.pdf

I had never thought about insulating the hose, so easy to do. Another small but incremental gain in performance of the air/oil separator.

I now have over 800 hrs on my RV-10 with the ASA oil/air separator with the exhaust negative pressure system and agree with your observations that cleaning the exhaust port on a std RV-10 install is approx. 35hrs. By 50 hrs. it is nearly completely blocked.


Very happy with the system and have been rewarded with a shiny clean belly for 800 + hrs. Having a belly mounted Airflow System Air/con condenser makes this system installation a must to keep the A/C Condenser free of oil slime.

RV-10 exhaust port at 50 hrs, not blocked and the safety valve had not opened at this stage but if not cleaned at the oil change it would of been blocked by the next oil change.
AM-JKLX10MQ74neQdMvPHT6ZsaO_DDh1Ckh0JjKUatDcY_aA7XYX6bmZ6SZdLXKWtTWF1FreBTl-1ZkeFj7L7AJQh5lD1fUQ0V2uRf_C1OmFHdRb_VbxUBNND3pSRmTbI_f7fQIhFZG6aAlsE3ZL6QATbSNOAQ=w509-h903


Please label your system clearly,
AM-JKLWb-acQGwFaWx-KG1J3XYQ9qKFGKbvSH_r8pkwpWYpd-7qyRZxffhgKPJK7dc7_0fAzqLwsPX1OjYOB2CbzcHEhMLG-_WqGobj8PBOx15bV1feM2OXglXeBiuXiR8f4sYOezwCfzdk9UEAwLl2qxP9hnA=w678-h903


AM-JKLVG5FgJSKw1zRLebrNBCekiW87Cv2hXpMwM4c4ldlVPclIEJ2gC9ydeCDW-4elEN53Tu5cO-QAiy9tcUj2QVa_ScWNAVbe_pphOIBc2s7Bpr1EjCWmRs36xWiBPhDyTOaKFtGJn2ZkZy3gvmQLSwXDmQA=w678-h903
 
Hey Dan,

What a great article,
https://www.danhorton.net/Articles/Separator-or-Condenser.pdf

I had never thought about insulating the hose, so easy to do. Another small but incremental gain in performance of the air/oil separator.

I now have over 800 hrs on my RV-10 with the ASA oil/air separator with the exhaust negative pressure system and agree with your observations that cleaning the exhaust port on a std RV-10 install is approx. 35hrs. By 50 hrs. it is nearly completely blocked.


Very happy with the system and have been rewarded with a shiny clean belly for 800 + hrs. Having a belly mounted Airflow System Air/con condenser makes this system installation a must to keep the A/C Condenser free of oil slime.

RV-10 exhaust port at 50 hrs, not blocked and the safety valve had not opened at this stage but if not cleaned at the oil change it would of been blocked by the next oil change.
AM-JKLX10MQ74neQdMvPHT6ZsaO_DDh1Ckh0JjKUatDcY_aA7XYX6bmZ6SZdLXKWtTWF1FreBTl-1ZkeFj7L7AJQh5lD1fUQ0V2uRf_C1OmFHdRb_VbxUBNND3pSRmTbI_f7fQIhFZG6aAlsE3ZL6QATbSNOAQ=w509-h903


Please label your system clearly,
AM-JKLWb-acQGwFaWx-KG1J3XYQ9qKFGKbvSH_r8pkwpWYpd-7qyRZxffhgKPJK7dc7_0fAzqLwsPX1OjYOB2CbzcHEhMLG-_WqGobj8PBOx15bV1feM2OXglXeBiuXiR8f4sYOezwCfzdk9UEAwLl2qxP9hnA=w678-h903


AM-JKLVG5FgJSKw1zRLebrNBCekiW87Cv2hXpMwM4c4ldlVPclIEJ2gC9ydeCDW-4elEN53Tu5cO-QAiy9tcUj2QVa_ScWNAVbe_pphOIBc2s7Bpr1EjCWmRs36xWiBPhDyTOaKFtGJn2ZkZy3gvmQLSwXDmQA=w678-h903

How are you cleaning the valve?
 
Hi Bill,

The valve has never needed a clean, just a wipe down with a rag. A quick suck and blow to verify operation and you are done.

To clean the mount pipe that goes into the exhaust pipe where the carbon builds up, simply use a large drill bit the same size as the pipe, push down and twist to dislodge the carbon and you are done.

(the whole inspection above took longer to type than to do)
 
Clean it often

A couple of weeks ago I added a picture to another thread, so I will redo it here. You REALLY need to pay attention to the attachment at the exhaust pipe, ESPECIALLY if you have an engine that has any kind of blowby, such as an older engine with low compression readings.
I've seen that the 6 cylinder engines seem to cause more of a problem than the 4 cylinder ones.

You can watch it on the Youtube channel this week if you want to see the blockage and hear the noise, as in this particular case the compression tests were causing loud noises to exit out of the exhaust. I knew we most likely didn't have multiple exhaust valve problems, and I could put my hand on the vacuum valve at the exhaust and feel it humming. 3 of the cylinders were in the low 60's, with one at 58, with an oily spark plug.

We pulled the separator tube off of the exhaust pipe and saw that it was 95% blocked. This one did have a bypass on it, but obviously this was still causing
backpressure. How do I know that? Well, when the customer showed up and we asked about any squawks, he mentioned that he was seeing more oil on the belly than usual. When we opened the cowling and looked at the engine, there was no single leak, but small leaks from everywhere, which is a sure sign of crankcase pressurization.

The youTube link is here: https://m.youtube.com/watch?v=koquiVeQg8M


Vic
 

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I’m hopeful that builders see that this system has more going against it than for it.

I have installed this air/oil separator on my old RV-10, but without the exhaust vacuum valve and with just a collection bottle on the separator 1/4” drain. The separator exit goes to just above the exhaust pipe. This works amazing well to keep oil off the belly and not have me worry about pressurizing the engine case.

Carl
 
You REALLY need to pay attention to the attachment at the exhaust pipe, ESPECIALLY if you have an engine that has any kind of blowby, such as an older engine with low compression readings.

Absolutely.

I've seen that the 6 cylinder engines seem to cause more of a problem than the 4 cylinder ones.

All with check valves installed on the tailpipe, yes? Valve installation on an individual headpipe would eliminate that particular difference and lower running case pressure too. A headpipe offers far greater wave amplitude. Tailpipe installs see small, weak waves.

We pulled the separator tube off of the exhaust pipe and saw that it was 95% blocked. This one did have a bypass on it, but obviously this was still causing backpressure. How do I know that? Well, when the customer showed up and we asked about any squawks, he mentioned that he was seeing more oil on the belly than usual. When we opened the cowling and looked at the engine, there was no single leak, but small leaks from everywhere, which is a sure sign of crankcase pressurization.

Was the bypass valve one of those tubular things Allen puts in his kits, or the hat shaped disc type check valve? The NAPA disc valve has a low opening pressure, while the Splat website says the tube valve is 0.5 psi. That's nearly 14" H2O, well above Lycoming's max of (IIRC) 4".

BTW, let's note a conventional open breather guarantees some positive case pressurization. It's normal. Just don't want a lot of it.

I’m hopeful that builders see that this system has more going against it than for it.

I'll take a few inches of negative case pressure.

I don't agree with some aspects of the Splat version. Mine works fine. An exhaust pipe breather outlet is standard on some Mooney models, and on TAT's turbo normalized kits for Cirrus, and has long been a feature of the Sky Dynamics collector. They all need cleaned from time to time.
 
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With my engine which was a new 2017 Lycoming now with 350 hours I check the pipe at the exhaust saddle at every oil change. There is usually a 1/8 inch ring of material. I clean it out using a small ball hone which works excellent. The check valve failed on my initial installation. Allen replaced it with another style which has been robust. Always check the valve for proper operation. I do like the results of using this breather air/oil separator.
 
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