[krwalsh]

I run an Anti-Splatt oil separator kit on my parallel valve IO-360-A1X, with the bottom connected with their exhaust kit through the check valve. I remove it every 50 hours, or at my annual condition inspection to verify that the port isn't clogged. It has never needed anything other than a minor scrubbing. But this time when I removed the valve to pull the exhaust port I was surprised to find it rattled in my hand. Upon inspection the rivet that holds the check valve assembly together, along with the spring, are missing. This is in a pusher application, which means the parts went through the propellor disk. I haven't yet fully inspected my prop to see if I can find any impact damage. My plane has ~150 hours on it, and this system was installed after my initial 40 hour Phase 1 testing was done, so it failed after roughly 100 hours in use.

These appear to be commercial, off the shelf air injection pump check valves, and looks to me like AV7T or GM 22040805 are like for like replacements. I contacted Anti-Splatt to see if this is a common failure, but I've not heard back.

Just a reminder that these systems do need periodic inspection and maintenance.

 

[pilotkms]

My original valve de-assembled itself at 800 hours. Replaced it with a Napa CRB 229003A. $20. It was guaranteed for life. Failed after 200 hours. Got it replaced for free. This new one has 300 hours and still as purchased. No rattle or disassembly. Just a standard replacement item in my book. RV Puller !

 

[Larco]

I run an Anti-Splatt oil separator kit on my parallel valve IO-360-A1X, with the bottom connected with their exhaust kit through the check valve. I remove it every 50 hours, or at my annual condition inspection to verify that the port isn't clogged. It has never needed anything other than a minor scrubbing. But this time when I removed the valve to pull the exhaust port I was surprised to find it rattled in my hand. Upon inspection the rivet that holds the check valve assembly together, along with the spring, are missing. This is in a pusher application, which means the parts went through the propellor disk. I haven't yet fully inspected my prop to see if I can find any impact damage. My plane has ~150 hours on it, and this system was installed after my initial 40 hour Phase 1 testing was done, so it failed after roughly 100 hours in use.

These appear to be commercial, off the shelf air injection pump check valves, and looks to me like AV7T or GM 22040805 are like for like replacements. I contacted Anti-Splatt to see if this is a common failure, but I've not heard back.

Just a reminder that these systems do need periodic inspection and maintenance.

I recommend calling AS as they were very helpful and and I think they have a great CS attitude. While on the phone I learned they had changed to a better valve which was installed and working as it should.
Larry

 

[olyolson]

Interesting, comparing the same type valve on the AntiSplat website shows this part for $75. It’s described as stainless steel so not sure what the Napa part is made from. The other part number, GM 22040805 can be purchased for $26 and the AV7T for $19. I like supporting AntiSplatbut is their part that special?

 

[Larco]

Interesting, comparing the same type valve on the AntiSplat website shows this part for $75. It’s described as stainless steel so not sure what the Napa part is made from. The other part number, GM 22040805 can be purchased for $26 and the AV7T for $19. I like supporting AntiSplatbut is their part that special?

I didn't pay 75.00. The valve does seems like a quality unit, all I did was recommend making a phone call and give them a chance to make it right. YMMV but they always seem to to be responsive in a positive manner?

 

[Walt]

Make sure you have an alternate relief valve of some sort, lest you be in big trouble if the vent gets blocked.

 

[JonJay]

I personally do not find the gain to be worth the risk. As I age with my RV, and flying in general, I continue to lean more and more towards simplicity. I can still get on my creeper and wipe the belly down…. It just isn’t worth it to me.
One example of how the RV’s have continued to get more and more sophisticated, and bloated.

 

[olyolson]

So do you just dump it overboard thru the exhaust? Does that give you a dirty belly?

 

[rocketbob]

I have inspected a number of these installed on RVs and found that not only can the check valve clog, but the standoff pipe clamped to the exhaust can get plugged as well. So be sure to look at that. The relief valve that they sell is advisable to install.

 

[krwalsh]

I got the AV7T today, and they’re effectively identical. A magnet sticks to both.

I have not had a relief valve on it, but I think I’ll be adding the “whistle slot” knife cut to the tubing.

Blowing through the failed valve it flows in both directions, so the failure mode of THIS ONE appears benign. But I could see this making for a very bad day. With the engine behind me I wouldn’t know I had a problem until I had a very serious problem.

 

[JonJay]

I got the AV7T today, and they’re effectively identical. A magnet sticks to both.

I have not had a relief valve on it, but I think I’ll be adding the “whistle slot” knife cut to the tubing.

Blowing through the failed valve it flows in both directions, so the failure mode of THIS ONE appears benign. But I could see this making for a very bad day. With the engine behind me I wouldn’t know I had a problem until I had a very serious problem.
View attachment 64561

The typical result of a coked up or stuck closed valve has been a blown out prop seal and immediate loss of all oil.

 

[Tracer 10]

Per Walt & his advice is well worth your time & effort. I have 2 relief valves on my RV6.
“Make sure you have an alternate relief valve of some sort, lest you be in big trouble if the vent gets blocked”.

 

[JonJay]

Per Walt & his advice is well worth your time & effort. I have 2 relief valves on my RV6.
“Make sure you have an alternate relief valve of some sort, lest you be in big trouble if the vent gets blocked”.

That’s prudent, but you just added two more things to the first thing. Without the first, you don’t need the others.
Not trying to be argumentative. We all make choices on what features we want in our machines and should weigh benefits vs risks. Few added features come with no risks.
Lots of these flying with very few issues, so i don’t want to chicken little this, but they are not problem free and a failure can be catastrophic.

 

[moosepileit]

I personally do not find the gain to be worth the risk. As I age with my RV, and flying in general, I continue to lean more and more towards simplicity. I can still get on my creeper and wipe the belly down…. It just isn’t worth it to me.
One example of how the RV’s have continued to get more and more sophisticated, and bloated.

I agree. Unless flying acro, I prefer the less is more approach. Find your sump's happy oil quantity and your breather exhaust's happy location.

6 quarts with a spin on filter is mine, uses a quart in 30 hours.

My breather is not down on to an exhaust pipe. That caused engine oil seeps. It was too restrictive and/or high air pressure. I tried up to an inch and a half above the left side crossover exhaust coming vertically down the RV-6 firewall and gave up that location. Had to be 1/4 of the way between the bottom of the firewall and the bottom of the lower cowl exhaust.

The crankcase evacuator is the 45 degree bevel cut on the end of the breather, same as it would be in the exhaust pipe systems.

The belly stays be plenty clean enough. Exhaust stain darkening, not oil blow, will dictate the belly clean creeper cycle. It should be needed at a fixed number of hours.

If the belly at the cowl exit changes at post flight wipe down and you didn't change your flying- your top end has changed. Likely oil consumption also changed. Let the plane show you early.

Just another way to look at it.

 

[rocketbob]

The typical result of a coked up or stuck closed valve has been a blown out prop seal and immediate loss of all oil.

No you wont lose ALL oil. Some. Maybe. I've installed a crank seal on an airplane that didn't have a crank seal installed at all. In that particular case there was only a small amount of oil mist.

 

[JonJay]

No you wont lose ALL oil. Some. Maybe. I've installed a crank seal on an airplane that didn't have a crank seal installed at all. In that particular case there was only a small amount of oil mist.

Just going off of one of the guys that posted here with an off field landing when his blew as a result of a coked up valve.

If the valve cokes up, you no longer have a crankcase vent and the case gets pressurized. Might make a difference compared to your experiences.

 

[DanH]

Make sure you have an alternate relief valve of some sort, lest you be in big trouble if the vent gets blocked.

Absolutely!

The typical result of a coked up or stuck closed valve has been a blown out prop seal and immediate loss of all oil.

Not if you install the relief valve.

Upon inspection the rivet that holds the check valve assembly together, along with the spring, are missing.

Second report of this failure mode, plus my own a few days ago. This particular NAPA valve was installed a long time ago.

Although the failure itself does not affect engine operation, you will see some oil mist loss through the relief valve. The problem is possible overheating of some adjacent component if/when the unblocked exhaust burns through the breather hose.

I'll consider possible revisions, but in the meantime, take a look at your installation and ensure there is nothing flammable or vital in the vicinity of the valve and attached hose.

 

[hgerhardt]

Second report of this failure mode, plus my own a few days ago. This particular NAPA valve was installed a long time ago.

It might be useful if all of you who've had a valve failure would report how many hours AND how many years these valves had before they failed.

If there's any pattern to it, then could recommend replacement at some interval. They're cheap enough to replace annually, but a waste if they last much longer than that.

 

[Carl Froehlich]

What I do. I use the Anti-Splat oil separator on the RV-10. I use the simple $100 ACS oil separator on the RV-8. Both work equally well. I do not use a valve into an exhaust pipe to draw a vacuum on the breather hose, and I do not return the separated oil to the engine. The large breather output of the separator does the standard termination over an exhaust pipe. My thinking:
- The marginal gain of using the vacuum feature is in the grass, and the risk (as has been discussed) is significant.
- I collect the separated oil instead of returning it to the engine as I did not want to do the plumbing, and when I empty the collection can (one pint metal can) I can keep track of how much oil is going out the crank vent. This Condition Inspection it was the typical 4-6 ounces. Not much but even that would create a mess on the belly. The engine burns ~1 qt. every ~25 hours.

The belly stays clean.

Carl

 

[DanH]

Doing some research today. The NAPA valve in common use here (https://www.napaonline.com/en/p/CRB229000) is a bit different as compared to the genuine GM part it replaced (GM 214-1047). And GM seems to offer both the original and what they call the "professional" line, a less expensive replacement...which appears to be identical to the NAPA part.

If descriptions are correct, the OEM GM valve has stainless steel internals and lasts a lot longer than the aftermarket parts. I've ordered a 214-1047, a Standard Motor Products AV7T, and I'll cut open the failed NAPA 2-29000. Stay tuned.

If you prefer a plain breather hose, that's cool. Overall I've been delighted with the system, and I'm willing to experiment.

 

[skylor]

No you wont lose ALL oil. Some. Maybe. I've installed a crank seal on an airplane that didn't have a crank seal installed at all. In that particular case there was only a small amount of oil mist.

If the engine without the seal had a functioning breather vent then there really shouldn't have been any significant gas flow through the crank seal area to motivate oil out the front of the crankcase. However, when an antisplat breather valve clogs and there isn't a a suitable pressure relief installed, all of the crankcase blow-by gas will end up flowing out through the seal area and carry nose-bearing oil runoff with it. There has been at least 1 documented case here on VAF of someone having had this happen somewhere in Arizona.

Skylor

 

[DanH]

However, when (any brand) breather valve clogs and there isn't a a suitable pressure relief installed, all of the crankcase blow-by gas will end up flowing out through the seal area and carry nose-bearing oil runoff with it. There has been at least 1 documented case here on VAF of someone having had this happen somewhere in Arizona.

Yep, Kurt, IIRC, popped the front seal. Happened to Vic too. Install the safety valve! All reported blockages of a exhaust tap were non-events when the pressure relief safety valve was also installed. A little oil mist on the firewall, that's it.

The new valves arrived. The OEM GM valve has a different shape and feels more substantial in terms of mass. The hot rod folks say it lasts longer. When I blew through it with my lips, as we would do as a functional check at each exhaust tap cleaning, it seemed to have a more powerful spring than the Standard Motor Products AV7T, i.e. it would need a bit more negative exhaust wave pressure to open. So I set up a simple measurement with a water manometer. Turns out my impression was correct, but not by much, 3" H2O vs 2"H2O.

I'll install the OEM GM valve and monitor its condition. I need to check a logbook for engine hours, but I'm pretty sure the NAPA 2-29000 valve it replaces was on there since 2016. So, I'll see how the GM valve ($99) holds up. The alternate plan might be to do as Heinrich suggested above; the Standard Motor Products valve is only about $20 on eBay, so just replace it at every annual.

 

[Scott Hersha]

Yep, Kurt, IIRC, popped the front seal. Happened to Vic too. Install the safety valve! All reported blockages of a exhaust tap were non-events when the pressure relief safety valve was also installed. A little oil mist on the firewall, that's it.

View attachment 65036

The new valves arrived. The OEM GM valve has a different shape and feels more substantial in terms of mass. The hot rod folks say it lasts longer. When I blew through it with my lips, as we would do as a functional check at each exhaust tap cleaning, it seemed to have a more powerful spring than the Standard Motor Products AV7T, i.e. it would need a bit more negative exhaust wave pressure to open. So I set up a simple measurement with a water manometer. Turns out my impression was correct, but not by much, 3" H2O vs 2"H2O.

I'll install the OEM GM valve and monitor its condition. I need to check a logbook for engine hours, but I'm pretty sure the NAPA 2-29000 valve it replaces was on there since 2016. So, I'll see how the GM valve ($99) holds up. The alternate plan might be to do as Heinrich suggested above; the Standard Motor Products valve is only about $20 on eBay, so just replace it at every annual.

View attachment 65037

View attachment 65038

View attachment 65039

OK, so I’m just a little bit confused about what I’m looking at in your pics. Is the item on the firewall with nothing on top of it the pressure relief valve? If so, is the item under the shiny tape also on the firewall the air/oil separator?
If so, your pressure relief valve looks just like what I have on my ASI vac system on the primary vacuum line. On mine the pressure relief is another, different looking T-shaped valve, valve plumbed into the line prior to that valve. I don’t have an air/oil separator. I couldn’t see a need for it since I’m just going to throw the effluent away. My belly gets no oil on it, but there is some build up of soot. I assume that is burnt oil. I clean my vac pipe out of coked oil every oil change (about 25-30 hours). It is never more that about 20-25% clogged. I also check the functioning of the T-shaped pressure relief valve. Assuming this post is not referring to what I have on my airplane? It’s just a problem on the air/oil separator system with no pressure relief?

 

[DanH]

Is the item on the firewall with nothing on top of it the pressure relief valve? If so, is the item under the shiny tape also on the firewall the air/oil separator?

Yes, and yes.

The relief valve may appear unfamiliar because I chucked it in the lathe and removed the unneeded nut. I faces up so G's don't open it.

The separator is insulated to help keep temperature above the dew point of the constituents with high vapor pressures...a separator, not a condenser.

If so, your pressure relief valve looks just like what I have on my ASI vac system on the primary vacuum line. On mine the pressure relief is another, different looking T-shaped valve, valve plumbed into the line prior to that valve.

Yes again. And the relief valve supplied by Splat is a cheaper substitute. Apparently it works.

Assuming this post is not referring to what I have on my airplane? It’s just a problem on the air/oil separator system with no pressure relief?

You have a check valve on the exhaust tap, yes? Then you too have the potential for a failed valve. The result is shown in post #17. Separator or none makes no difference.

 

[airguy]

Yep, Kurt, IIRC, popped the front seal. Happened to Vic too. Install the safety valve! All reported blockages of a exhaust tap were non-events when the pressure relief safety valve was also installed. A little oil mist on the firewall, that's it.

The alternate plan might be to do as Heinrich suggested above; the Standard Motor Products valve is only about $20 on eBay, so just replace it at every annual.

Not sure replacement at annual is really called for - my original ASI valve has 1650 hours and 8 years on it, with cleaning at each oil change, no issue so far. And yes, I have the pressure relief valve.

Of course, to be fair, I also do throw away 8 "perfectly good" automotive spark plugs at each annual because they are so cheap to replace, so I'm not going to wave that flag too vigorously.

 

[DanH]

Not sure replacement at annual is really called for - my original ASI valve has 1650 hours and 8 years on it, with cleaning at each oil change, no issue so far. And yes, I have the pressure relief valve.

Of course, to be fair, I also do throw away 8 "perfectly good" automotive spark plugs at each annual because they are so cheap to replace, so I'm not going to wave that flag too vigorously.

Greg, is your valve installed on a tailpipe, or on the head pipe for a single cylinder? I ask becasue the magnitude of the exhaust wave pressure deltas (positive to negative) will be larger in a single cylinder's headpipe.

 

[airguy]

Greg, is your valve install on a tailpipe, or on the head pipe for a single cylinder?

I have the Vetterman crossover exhaust, mine is installed on the right hand tailpipe of the engine immediately after the joint of the two pipes. Here's a pic from my build files.

 

[DanH]

I have the Vetterman crossover exhaust, mine is installed on the right hand tailpipe of the engine immediately after the joint of the two pipes. Here's a pic from my build files.

Ok, that's going to be easier on the valve.

Here's an illustration taken from an old CAFE report. This was taken with a 4-into-1, but the principle is similar for a crossover. The crossover exhaust ties together two opposing cylinders, so they send major pressure waves up and down the pipe 360 degrees out of phase with each other. The result is some degree of mechanical averaging in the connecting tailpipe, with the two sets of waves (here P1 and P2) in opposition at various points in a 720 degree cycle.

Note for those folks unfamiliar with basic principle; the check valve exposes the engine breather to the negative waves, while sealing it off from the positive. In some ways it's like a half wave rectifier applied to an AC alternator output.

 

[Scott Hersha]

My setup is similar to Greg’s except that I don’t have the air/oil separator. I do have the pressure relief mounted upstream from the Antisplatt check valve, which is not mount directly to the exhaust pipe.

In order for mine to get plugged and unable to pass gas - it seems like the tube inside the exhaust pipe would have to coke up completely, or the check valve would have to plug up somehow, and then the relief valve - brass in the second pic - would have to fail as well. The gold colored part in the first pic is a one way check valve. I check all these parts at every oil change. I’ll usually find a small amount of coked oil in the tube that’s inside the exhaust pipe, but nothing in the other two parts. I flush those with solvent to make sure they’re clean and check functionality by blowing in them. It seems like a pretty fool proof system, and my belly is clean.

No question, a plain straight breather line running out the bottom of the cowl is fool proof, but the vac system, if installed correctly and maintained properly, should be quite safe.

 

[DanH]

All true Scott, but again, the problem under discussion here is failure of the diaphragm rivet inside the check valve. Your valve is the same or similar. Post failure, with the diaphragm rattling around loose, hot exhaust gas is no longer blocked and can burn through the hose, as pictured in post 17.

 

[Scott Hersha]

OK……. now I’m beginning to understand. I’m probably going to go back to the old vent pipe down the firewall. An oily belly might be easier to clean than the burnt soot I deal with now, although I don’t need to do that very often. Keep it simple. I’ll need to figure the best way to patch the hole in my exhaust pipe. I’m not a welder. Maybe just clamp on a piece of chromoly.

 

[Tom023]

I had the same failure as Dan about a week earlier than he did at 21 hours on the Napa valve mounted 11" from the #4 exhaust port . The system has significantly reduced my oil consumption so I am trying another Napa valve in case mine was just a defect, and may try the GM valve if necessary. If I continue to have failures I will just cap the exhaust tap on go back to the firewall mounted breather hose.

 

[JonJay]

The system has significantly reduced my oil consumption….

Consumption or loss? Many of us can not run more than 5 qts or it just blows out the breather…..

 

[Tom023]

Consumption or loss? Many of us can not run more than 5 qts or it just blows out the breather…..

Loss is probably the correct term. It does go out the breather but it doesn't matter what the level is, I've tried them all. Could be the positioning of the breather tube, but I tried several. Installing the air/oil separator by itself did nothing to help so I installed the exhaust tap and oil "use" went from 6 to 9 hrs/qt. This is a 390 so oil use tends to be high anyway. The tap has also allowed me to run 6 or 7 quarts and not have it blow out...which helps keep oil temps lower, which also run higher on the 390, especially in the Texas heat of summer, so I do get some benefits from the system. If the next two valves don't stay together for a year each, however, I'm going to pull everything off and go back with a straight breather.

 

[Scott Hersha]

Slight change in plan. I really like the vac system I installed on my airplane, and I too don’t mind doing a little experimenting. I thought about calling Clint at Vetterman and ordering a new tail pipe, but trying to fix a potential problem with better parts would be easier, not that I’m lazy. Well maybe I am a little lazy, but I like the way the vac system works. I ordered the genuine GM part (214-1047). I’ll replace my NAPA unit and dissect it to see what’s inside. The GM valve has a three year warranty - not that it matters in an airplane, but might indicate more robust construction. I‘ve only been flying my plane less than two years, 162 hours, so my NAPA valve might not look so bad inside. Plus mounted like Greg’s might be a less stressful environment than some as indicated above.

A word of caution for anyone purchasing the GM valve. In my hometown it is available at NAPA, Auto Zone, O’Reilly, and even Home Depot for $99. It’s also available on Amazon for $99. If you choose Amazon be aware there are identical looking valves for $49. They even have the part #214-1047. The GM unit is made by ACDelco in the USA. The clones are made in China.

 

[Scott Hersha]

Amazon delivered my new GM check valve today. I removed the old one to compare. See pics. They look about the same, except for one obvious difference. The inlet is 3/4” On the new GM part. My crankcase vent fitting and hose is 5/8”. I’ll have to get a 5/8 to 3/4 barbed adapter and a short piece of 3/4” hose. There will be a pretty populated collection of hose clamps in a short distance. Starting to become more of a pain than it’s worth. The Amazon site didn’t have details, but based on what I read here, I thought I had it right. I should have checked the GM parts website for specs - my bad. The two check valves don’t look much different, other than the color and the inlet size. The GM one is .08 oz heavier which I assume is because of the slightly larger exterior metal. Not sure where I’m going to go from here. Anybody that wants a new genuine GM 214-1047 at a discount, let me know.