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View Poll Results: Your experience with Air/Oil separator
I installed one and finds it very effective with no oil on the belly 20 22.73%
I installed one which drastically reduced oil on belly 39 44.32%
I did not install one and run the engine with lower oil level 19 21.59%
I am planning on installing one 12 13.64%
Multiple Choice Poll. Voters: 88. You may not vote on this poll

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  #21  
Old 11-15-2019, 07:46 AM
DanH's Avatar
DanH DanH is offline
 
Join Date: Oct 2005
Location: 08A
Posts: 10,356
Default

Quote:
Originally Posted by Tracer 10 View Post
We installed the Anti Splat Air/Oil Separator with exhaust check/vacuum valve that develops a very slight negative pressure on the engine crankcase. Huge improvement on oil residue on the belly. It also increased RPM at takeoff.
How much increase? Theory says it should.

Quote:
***CAUTION*** YOU MUST INSPECT THE CHECK VALVE AND CLEAN ANY CARBON RESIDUE OUT OF THE VACUUM VALVE EVERY 100 HOURS OR ANNUALLY.
Thanks for mentioning that Milon. It cannot be stressed enough.

Rather than "100 hours or annually", I'd suggest developing a cleaning schedule based on early observation of the particular installation. Technically, it is not the valve which needs cleaned, but rather, the tubular tap into the exhaust system. There have been reports of total blockage at less than 50 hours for Anti-Splat RV-10 exhaust taps mounted on the tailpipe. Even after establishing a rate of accumulation, I'd keep an eye on it, as it may accumulate coke more rapidly as the engine ages and puts more oil out the breather. A change in the usual operating RPM can also make a difference.

Exhaust tap on my 390. It's welded, not clamped. Note bracing; I'm not a big fan of just welding a tube into a hot, vibrating header pipe and allowing it to cantilever without support. The disk is a heat sink; the reed valve stays cool (yes, I measured).



This is the coking problem. The little bit of aerosol oil which reaches the hot exhaust tap can accumulate and eventually block the tap. It seems to build up as a ring of material, but individual applications may vary.



The tap as shown would go more than 140 hours without blockage. One experiment was to see if the rate of accumulation could be slowed even more by installing an insulated liner tube:



It's been in there a few hundred hours now. I clean with an appropriately sized drill bit at each 50 hour oil change, so I've had plenty of opportunity for observation. In my opinion, it didn't result in any significant improvement. Although it may accumulate coke at a slower rate, the smaller ID is faster to block. I'll probably remove the liner tube the next time the pipes are off the engine.

In any case, all installations should have a relief valve tee'd into the line between the separator and the exhaust tap. It's the same NAPA #2-29000 reed valve, installed so vacuum keeps it shut and positive pressure cause it to open. It just sits there doing nothing most of the time, but if the exhaust tap should coke shut, engine case pressure will vent via the relief valve and the engine won't blow seals. I'm aware of at least one instance where it happened and the relief worked, so just do it.

This particular relief valve has had the integral mounting nut machined off to save a few ounces.

__________________
Dan Horton
RV-8 SS
Barrett IO-390
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  #22  
Old 11-15-2019, 03:58 PM
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ChiefPilot ChiefPilot is offline
 
Join Date: Jan 2005
Location: Twin Cities, MN
Posts: 1,580
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I made a simple one out of aluminum tubing and some aluminum bar stock. It is mounted such that it simply drains back into the breather port on the back of the engine but is otherwise derived from Tony Bingelis' design. Dropping the velocity and providing lots of surface area for the droplets to coalesce onto are key.



Filling with eight quarts of oil after an oil change then flying for an hour leaves the belly clean and dry. Can't ask much more of it.
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Brad Benson, Maplewood MN.
RV-6A N164BL, Flying since Nov 2012!
If you're not making mistakes, you're probably not making anything

Last edited by ChiefPilot : 11-15-2019 at 08:17 PM.
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  #23  
Old 11-15-2019, 08:29 PM
rightrudder rightrudder is offline
 
Join Date: Mar 2014
Location: Laguna Hills, CA
Posts: 1,853
Default

No air/oil separator here; none needed. I clean the belly once a year at annual, and there's not that much accumulation.

Lighter, simpler, less expensive.
__________________
Doug
RV-9A "slider"--sold in July 2021
Flew to Osh in 2017, 2018 & 2019!
Donation made for 2021
You haven't seen a tree until you've seen its shadow from the sky -- Amelia Earhart
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  #24  
Old 11-19-2019, 09:49 PM
Tracer 10 Tracer 10 is offline
 
Join Date: Mar 2011
Location: Oregon
Posts: 152
Default There have been reports of total blockage at less than 50 hours for Anti-Splat RV-10

Quote:
Originally Posted by DanH View Post
How much increase? Theory says it should.



Thanks for mentioning that Milon. It cannot be stressed enough.

Rather than "100 hours or annually", I'd suggest developing a cleaning schedule based on early observation of the particular installation. Technically, it is not the valve which needs cleaned, but rather, the tubular tap into the exhaust system. There have been reports of total blockage at less than 50 hours for Anti-Splat RV-10 exhaust taps mounted on the tailpipe. Even after establishing a rate of accumulation, I'd keep an eye on it, as it may accumulate coke more rapidly as the engine ages and puts more oil out the breather. A change in the usual operating RPM can also make a difference.

Exhaust tap on my 390. It's welded, not clamped. Note bracing; I'm not a big fan of just welding a tube into a hot, vibrating header pipe and allowing it to cantilever without support. The disk is a heat sink; the reed valve stays cool (yes, I measured).



This is the coking problem. The little bit of aerosol oil which reaches the hot exhaust tap can accumulate and eventually block the tap. It seems to build up as a ring of material, but individual applications may vary.



The tap as shown would go more than 140 hours without blockage. One experiment was to see if the rate of accumulation could be slowed even more by installing an insulated liner tube:



It's been in there a few hundred hours now. I clean with an appropriately sized drill bit at each 50 hour oil change, so I've had plenty of opportunity for observation. In my opinion, it didn't result in any significant improvement. Although it may accumulate coke at a slower rate, the smaller ID is faster to block. I'll probably remove the liner tube the next time the pipes are off the engine.

In any case, all installations should have a relief valve tee'd into the line between the separator and the exhaust tap. It's the same NAPA #2-29000 reed valve, installed so vacuum keeps it shut and positive pressure cause it to open. It just sits there doing nothing most of the time, but if the exhaust tap should coke shut, engine case pressure will vent via the relief valve and the engine won't blow seals. I'm aware of at least one instance where it happened and the relief worked, so just do it.

This particular relief valve has had the integral mounting nut machined off to save a few ounces.

I completely agree with Dan?s statement about cleaning every 50 hours at oil change. The first 50 hours ours showed some accumulation of gunk. It decreased every 50 hours thereafter. We gained about 75 RPM.
__________________
CW4 (Retired) U.S. Army
A&P: I pay double dues (it's worth it)
Restored L2-M; flown 7 years & sold.
Flying Oregon RV-6
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  #25  
Old 11-19-2019, 09:52 PM
Tracer 10 Tracer 10 is offline
 
Join Date: Mar 2011
Location: Oregon
Posts: 152
Default There have been reports of total blockage at less than 50 hours for Anti-Splat RV-10

Quote:
Originally Posted by DanH View Post
How much increase? Theory says it should.



Thanks for mentioning that Milon. It cannot be stressed enough.

Rather than "100 hours or annually", I'd suggest developing a cleaning schedule based on early observation of the particular installation. Technically, it is not the valve which needs cleaned, but rather, the tubular tap into the exhaust system. There have been reports of total blockage at less than 50 hours for Anti-Splat RV-10 exhaust taps mounted on the tailpipe. Even after establishing a rate of accumulation, I'd keep an eye on it, as it may accumulate coke more rapidly as the engine ages and puts more oil out the breather. A change in the usual operating RPM can also make a difference.

Exhaust tap on my 390. It's welded, not clamped. Note bracing; I'm not a big fan of just welding a tube into a hot, vibrating header pipe and allowing it to cantilever without support. The disk is a heat sink; the reed valve stays cool (yes, I measured).



This is the coking problem. The little bit of aerosol oil which reaches the hot exhaust tap can accumulate and eventually block the tap. It seems to build up as a ring of material, but individual applications may vary.



The tap as shown would go more than 140 hours without blockage. One experiment was to see if the rate of accumulation could be slowed even more by installing an insulated liner tube:



It's been in there a few hundred hours now. I clean with an appropriately sized drill bit at each 50 hour oil change, so I've had plenty of opportunity for observation. In my opinion, it didn't result in any significant improvement. Although it may accumulate coke at a slower rate, the smaller ID is faster to block. I'll probably remove the liner tube the next time the pipes are off the engine.

In any case, all installations should have a relief valve tee'd into the line between the separator and the exhaust tap. It's the same NAPA #2-29000 reed valve, installed so vacuum keeps it shut and positive pressure cause it to open. It just sits there doing nothing most of the time, but if the exhaust tap should coke shut, engine case pressure will vent via the relief valve and the engine won't blow seals. I'm aware of at least one instance where it happened and the relief worked, so just do it.

This particular relief valve has had the integral mounting nut machined off to save a few ounces.

I completely agree with Dan?s statement about cleaning every 50 hours at oil change. The first 50 hours ours showed some accumulation of gunk. It decreased every 50 hours thereafter.
__________________
CW4 (Retired) U.S. Army
A&P: I pay double dues (it's worth it)
Restored L2-M; flown 7 years & sold.
Flying Oregon RV-6
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  #26  
Old 11-21-2019, 12:58 AM
Tom @ N269CP Tom @ N269CP is offline
 
Join Date: Oct 2017
Location: Green Cove Springs, FL
Posts: 129
Default

I installed an AntiSplat oil mist separator with the collected oil drained back to the crankcase. However, we routed the vent line overboard in the vicinity of the exhaust outlet. Did not tie the vent line back into the hot exhaust to avoid potential coking/plugging problems. Works fine and greatly reduced oil on the belly versus w/o the separator.

The main contaminant on my belly is lead deposits from the engine exhausts.
__________________
Kind regards,

Tom

==================================
RV-8 N269CP
O-360-A1A w/Hartzell CS prop on 100LL
Slick-IC+PMag ignitions
Steam gauges
EI UBG-16, FP-5, & MUX-8A datalogger
Garmin Aera 660
TruTrak ADI Pilot II (GPS coupled)
Garmin GDL39 3D ADSB-In
uAvionix Tailbeacon ADSB-Out
Infinity grip w/Matronics trim speed control
Reiff preheater system
TCW oil cooler air damper w/servo drive
AntiSplat oil mist separator
Mountain High O2D1 O2 system

Location: Durango, CO (KDRO)
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