slime fighter

[av-mech]

Thought you might like to see the installation of my "slime fighter" on my oil breather hose.

[Bill James]

Very clean looking. (For the occasional visitor to the site here, you can only see the attached images if you are signed-in).
For fun, having used several Rube Goldberg apparatus’ -  a couple of questions.
What does it do? Slow down the airflow, catch the oil vapor, …you just install it and then something magic happens…?
We have all heard, to avoid blowing out the crank seal, that a case vent must retain the ¾ inch inside diameter. Is there a concern of back pressure?
Thanks for another detail to chase 

[BruceHughes]

I am also wondering what it is supposed to do.   My guess is that it just makes money for the company that sells it. 
That unit MIGHT be useful on airplanes that are NOT pusher.

Be sure that you have a cut at the high point just above the breather fitting in case of stoppage and backpressure.
I have just a plain tube all the way to the trailing edge of the wing, supported internally with springs so it does not
collapse.   

It does NOT go above the engine.

Your sensor lines to the CHT sensors on #1 and #3 are not supported in any way.  The ones to #2 and #4 must be the
same.   I think you will find one or more breaking very soon.   

You need some expert to look at that entire engine.   I had a problem with unsupported primer lines which I am fixing
today.  I fixed it once but that was not good enough.

Fly safe out there.   

Bruce Hughes   

[av-mech]

The slimefighter has a set of floating disks inside that allow the oil to collect on them as it enters the chamber.  The oil flows off the disks and drains back down the tube as a solid instead of the vapor that it was when it came out of the case.  I had a simple tube running forward and up, passing through the baffling and then making it's way out to the right aft corner of the lower cowling.  I was getting oil on the trailing edge of the cowling on the right side.  Turns out that the slime fighter did help this scenario but did not eliminate it as I had hoped.  I started thinking that maybe I was getting a little to much crankcase pressure and decided to do a compression check (hot) after flying today.  All cylinders were in the mid 70's.  I am starting to think that there may just be enough low pressure at the outboard trailing edge of the cowl that it's creating too much suction and its pulling oil out.  I did not have a vent hole on the hose and I have put one in now, won't know how well that works until I fly again tomorrow.  I am hoping that it will provide a vent for the suction in the hose.

Bruce, I disagree with you on the CHT lines.  Look close and you will see that there is an adel clamp holding them at the center of the engine, then where they get close to the cylinders I have cushioned them with high temp RTV and then it's just a short turn to the plug holes where they terminate. 

[av-mech]

Bruce,

Additionally I would disagree with you on your comment concerning the slimefighter "only" making money for the company that sells it.  It did work on my aircraft even if it did not eliminate the problem completly.  I would advise a more diplomatic approach to your comments on items you have not researched, held in your hand or even tried on your aircraft. 

Could you please explain your position on why it would be better for aircraft that are not pushers.

I have had several "experts" look at my entire aircraft and all have found it to be safe and airworthy in all regards.  I have flown the first 12 hours with virtually no squawks and only minor adjustments so I feel like to this point, I have done a good job with how I have prepared the aircraft.

[BruceHughes]

I apologize for saying anything.  Maybe I could have said it more tactfully. 

You still did not say what it is supposed to do.  What "problem" are you referring to?

I would never run a rubber hose across an engine case.

I still think you have a problem with those CHT leads.

No matter how much looking anyone makes, there are things that can be overlooked.
Get people to look at your project.

BH

[Joe Person]

I've run my high-quality polyurethane breather tube, with internal CRES spring, across the top of my engine, for 450 hours now, and it is still in condition for safe operation - the material remains supple, with no evidence of embrittlement, etc.  Don't want to run a polymer hose across the engine case? With updraft cooling, it helps ensure you won't freeze any moisture in the line.

As for one of our newest canard members, I think having both an A&P AND Inspection Authorization quite possibly speaks for extensive aviation experience, or am I missing something...   

[BruceHughes]

None of Bill James's questions have been answered.....

[av-mech]

I believe I did answer his question of "what does it do".  It returns oil to the CC by allowing the vapors to deposit oil on the disks inside the canister.   The liqud oil runs back down the oil breather tube and into the engine.

My Varieze is a rebuild job.  the airframe was complete but structurally damaged when I bought it.  As such there were things already attached to the airframe that I simply hooked back up when I rebuilt it.  One of those things was a small aluminum tube mounted on the outboard lower cowling (right side), it was the overboard for the CC breather.  The problem I have had is that it seems to be sucking an excess amount of oil out of the engine and leaving a lot of it on the cowling.  The engine was a direct transplant from my Cessna 150 which was flown regularly and did not lose the same amount of oil via the breather.  I installed the slime fighter to see if it would resolve the problem.  For the most part it did but I still have a little oil coming out.  I have cut a vent hole in the breather tube in hopes that it will vent anymore suction that is on that line.  See picture for location of breather line termination.  I suspect that there is a vacuum being created there.

[av-mech]

BTW, you can see that I haved some cosmetic work yet to do on the cowlings.  Please forgive me for not getting that done before OSH.  I have changed the exhaust system from the original design and have not had time to fix up the cowlings yet.

[easyrider]

I have run a Slime Fighter on my O-235 Long for about 50 Hrs, no problems.
I also run a carheater hose from the Slime Fighter along the top of the block through the front baffle and back under cyls 2&4 to exit into the header for cyls 2&4.
I keep the pipe off the block with Addel clamps.
I intend to blow air through the Slime fighter at the block fitting every oil change.
Easyrider

[av-mech]

Bill,

I checked the O-200 overhaul manual and it has two pieces of interesting information.

1.  Crankcase pressure measured using a manometer should not exceed 1".  the manual does not mention how to hook up a manometer to the engine case, any thoughts on that??

2.  The oil breather fitting is 5/8" dia, which is smaller than the 3/4" you mentioned.  I don't know about blowing the seal out using anything smaller than 3/4" but maybe it has something to do with the length of the hose casuing some extra back pressure?? 

[Joe Person]

Arnold,

Best way to "tap" the pressure off of a O-200 is with either a oil filler cap modified with a hose barb brazed to it, or a homebrew rig that allows for the same type of bayonet fixity to the oil filler tube.  I made the latter version with some scrap aluminum and a barbed hose fitting threaded into the aluminum plate that makes up the cover.  Seal is a scrap piece of silicone baffle material.  Two tabs with screws form the bayonet section.  I use a simple U-tube manometer.  You may have a bit of a vacuum effect where your breather exit is - mine runs out the right side as well, but is closer to the prop hub than being outboard.  An Adel clamp with an addtional worm clamp for safety positions an aluminum tube downward and out, with the clamp bolted to a reinforced section of the aft baffle.  Works like a charm, and I lose only drops of oil.  As I noted, my breather tube runs in a 180 degree loop across the top of the O-200.  It is secured to the lifting eye.  I also use the "Aerobatic" breather elbow, made by brazing a short section of tubing on the threaded end.  With wht crankshaft config and the vacuum pump gear at the prop end of the O-200, the stock breather can yield extra oil out the elbow.   See the following website for details:

http://www.mooneymite.com/maintenance/continentalbreatherfix.htm

My O-200 runs about a half-inch of case pressure, FWIW.

Cheers,

[Bill James]

Very interesting guys. Always a better way to skin a cat.
      Yuck. Anybody ever done that? On purpose?
I continue to revere the CP exaltation that the case vent tube must be clear, therefore always using the clear hose rather than rubber or colored   
I believe that once upon a time i probably caused a crank seal to seep before its time, so I appreciate the different details here.
                                                                             Here kitty-kitty.

[av-mech]

Joe,

That's a ton of great information.  I did find today that the vent hole in the top of my breather hose did little to abate the problem.  I am going to change to position of where the tube overboards and also add the extension to the breather fitting.  I had that fix hanging in my back pocket if all else failed.

Flew the eze down to Plant City from Leesburg this afternoon.  Climbed to 5500, just below the puffies and cruised along listening to the XM radio (blues station).  I don't have pants or cuffs and my prop is not quite right but I still made 159 KTS GS in cruise congfiguration.  Letting down at about 500 fpm I just left the power up and was seeing 180 KTS GS.  I called 5 miles out and almost immediatly found myself calling left base!!  One guy at the airport said I looked like a supersonic gnat!!  Going home was a little slower due to a headwind but I guess you can't win'em all......  I was light on fuel and the plane was behaving well.