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Warning From Anti-Splat!!!!!!

PerfTech

Well Known Member
...Today I received a phone call from one of the fellow members of this forum that we feel needs to be passed on to everyone. He called to inform us of an issue that he had with one of our vacuum evacuation systems. This is a very knowledgeable and respected member here, so his issue is real and needs to be addressed. He installed one of our systems approximately one hundred hours ago on his 600 hour engine and it has developed a problem. The stainless tube that the vacuum valve attaches to had coked up where it enters the exhaust system, thus preventing the engine from breathing properly. It was necessary to remove the valve and clean the tube of carbon and deposits to fix the problem. With approximately 5000 of these units out there in service, I personally have not seen this happen. Larry Vetterman told me that he used to install lots of these over the course of the many years he has been flying and building aircraft. He said that he had seen a few that had plugged up after long extended use. We heeded his advise and suggested that at annual time the valve be removed and the tube cleaned. Due to this recent report, we think it should be revised and this operation should be done at each oil change, or 50 hours maximum to be certain that this condition doesn't come up again. If no signs of the problem show up, then one my consider extending the cleaning intervals. We would appreciate a phone call or an e-mail report to [email protected] from anyone that finds a build-up of deposits in their tube so we can evaluate the potential of the issue. If this tube closes off the engine can build some crankcase pressure and will show oil leaks where the air is trying to escape. This is not what we want to see and ask that everyone with this system take a few minutes next time you have access and check yours. We are very sorry to post this request, but feel in the interest of safety it is necessary. Regards all, Allan...:eek:
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I had been running this same exhaust check valve (not the mount sold by anti-splat, just the check valve) which I welded into the exhaust pipe tip within about 4 inches of the end. Mine definitely built up a significant amount of hard residue, enough to occlude more than 50% of the pipe diameter within 100-200 hours. I have chromed cylinders on 3/4 of my o-320 and lose 1 quart every 2 hours or so. My oil drain pipe was welded flush with the lumen of the exhaust pipe which I do not know if is a factor or not. I just removed mine and replaced it with the one sold by anti-splat pictured above due to my pipe partially cracking and bending at the weld to the exhaust pipe. Installed close to the exhaust outlet, I could clean mine by inserting a hooked tool into the exhaust pipe without the hassle of removing the cowling.
 
Anit-Splat mod?

Would a whistle slot help? I refer to the same thing we do to normal breather tubes - a slot within a couple inches of the end of the tube. Seems the vacuum created by the exh stream across the end would be somewhat reduced....

DanH's suggestion of an opposite facing reed valve is a more elegant solution, but it adds weight and complication.

Plugged breathers are very bad juju.

Carry on!
Mark
 
I had been running this same exhaust check valve (not the mount sold by anti-splat, just the check valve) which I welded into the exhaust pipe tip within about 4 inches of the end. Mine definitely built up a significant amount of hard residue, enough to occlude more than 50% of the pipe diameter within 100-200 hours. I have chromed cylinders on 3/4 of my o-320 and lose 1 quart every 2 hours or so. My oil drain pipe was welded flush with the lumen of the exhaust pipe which I do not know if is a factor or not. I just removed mine and replaced it with the one sold by anti-splat pictured above due to my pipe partially cracking and bending at the weld to the exhaust pipe. Installed close to the exhaust outlet, I could clean mine by inserting a hooked tool into the exhaust pipe without the hassle of removing the cowling.

That seems to set a worse case scenario for the system.

Lycoming's limit on oil consumption is 2.05 hrs/qt for a 150 HP engine.

If you block 50% in 100-200 hours then Allan's inspection times seem quite conservative...
 
Cause I'm a freak for redundancy and I was worried about a valve failure, I put one on each pipe... Copied the set up on a friends hot rod jet boat. Secretly hoping for a little more vacuum, as well, but know that was not likely. Does that mean I can go 100 hours ? :)
 
Reed valve

Dan. Did you put one of those b/u reed valves on your setup? I copied your setup and it has worked great! Do you have a part number for the b/u valve that you have used and are happy with? Thanks a bunch. Dave
 
Dan. Did you put one of those b/u reed valves on your setup? I copied your setup and it has worked great! Do you have a part number for the b/u valve that you have used and are happy with? Thanks a bunch. Dave

"b/u" = backup? No, not yet. I'm happy to monitor at 50 hr intervals and see if there is any buildup.
 
Update!

....We have sent an e-mail to all buyers and users of this product stating the new recommendations for maintenance and inspection. Many people don't frequent the forums and as it is hard to believe, some aren't even aware of their existence. At any rate we have notified all buyers of our vacuum evacuation product of the suggested changes. Thank you, Allan...:D
 
That is one of the reasons I come here every day. Every RV owner should be a part of the forum if for no other reason than posts like this. Every time a problem or concern is posted it gives us all a heads up.
 
Reports In!!!

....We have now gotten about 75 or so reports back from users that we sent e-mail to about this possible issue. We are pleased to say that none have any build up of scale etc. so far. At this point it looks as if it is an isolated event and not the norm. Thank you all for the reports. Allan...:)
 
Update from ASA

.... just an update on our vacuum valve recommendations. We are very pleased to report that to date no other reports of clogging or build-up of any kind have surfaced. We would like to say thank you to all who have checked this and reported back to us. We know this was somewhat of an imposition and we apologize. It is better safe than sorry. Thanks all, Allan...:D
 
One more sample to add to your database. After 50+ hours, no buildup whatsoever. Nice tan color just like the rest of the pipe.
 
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