Oil catch can ideas?

[Old Koreelah]

I want to replace the simple oil vent catch can on my Jabiru engine with a canister to collect oil and return it to the sump. On longer flights this might prevent running low on oil.

 

I'd like to use the CAMit design, but it requires dismantling to drill an oil-return hole in the casing.

 

I can't seem to find one ready-made; people suggest I build my own.

 

My solution: a home-made flat canister mounted close to the dipstick so oil mist can enter, be condensed out and accumulate. Water vapour and other nasties can pass out thru a tube at the top, routed down under the aircraft.

 

Problem: how to allow the oil to accumulate in the catch can without blocking the single small entry hole?

 

Solution: slope the flat canister so that oil can only drain back into the engine when aircraft is sitting on tail wheel.

 

I have only a vague idea of what's actually inside a functioning unit; I'd rather use metal mesh than stainless steel kitchen scourer (I don't want scrap metal draining back into the engine).

 

Any suggestions and advice welcome.

 

 

[frank marriott]

Now available at Jabiru.

 

 

[Downunder]

Search "provent".

 

I'm not sure if they make a model small enough for you but these are made in Germany and designed to do exactly what you want.

 

 

 

[aj_richo]

I saw an item like these at Sprint Autoparts recently, black plastic almost identical to the items in the first few seconds of the video.

 

Came in a box about 100 x 100 x 140 deep.

 

Looked like it would be easy to attach to my engine mount and connect to the filler outlet, but seems to have extra connection for pcv valve?

 

I guess it could be blocked off.

 

 

[Downunder]

The "provent 100" looks to be the smallest by MANN.

 

About 3 inches round by 6 long.

 

 

[Old Koreelah]

 

Now available at Jabiru.

Thanks Frank and everyone else who responded. Jabiru sent me some pix this arvo. Apparently this unit replaces the oil filler T. Will get more info tomorrow.

Meanwhile, I'd be interested to hear of anyone's experience of this unit.

 

 

 

[facthunter]

I wouldn't in any circumstances return any of that contaminated oil to the engine. If you want to stop oily belly empty it out now and again. Nev

 

 

[Old Koreelah]

I wouldn't in any circumstances return any of that contaminated oil to the engine. If you want to stop oily belly empty it out now and again. Nev

That was originally my opinion Nev, but I was advised that these units allow moisture and other volatiles to be boiled off, so that oil being returned to the engine was kosha.

My catch bottle has worked okey for years, but my engine is now using oil, so I'd like to re-use it for longer trips.

 

 

[facthunter]

Your call. When and where is the moisture "boiled off"? You'd be better to have a way of pumping a bit of new oil in from a remote tank for longer trips. I've seen the mess that gets in those places where the moisture condenses. Water forms acids with most products of combustion, in pretty high concentrations. You'd have to go to over 120 degrees (well over). It would remain highly contaminated. Still need treatment with chemicals and for so small an amount not worth the risk. Nev

 

 

[Guest DonC]

That was originally my opinion Nev, but I was advised that these units allow moisture and other volatiles to be boiled off, so that oil being returned to the engine was kosha.My catch bottle has worked okey for years, but my engine is now using oil, so I'd like to re-use it for longer trips.

If there's that much blowby the engine needs reconditioning!

 

 

[facthunter]

That is quite true. Blowby kills half dead engines with contamination. If you has a flowmeter in the breather you could measure it as you operate. Similar to the ones on an argon bottle. Nev

 

 

[bexrbetter]

Oh for goodness sakes, one word: PCV. Ok, ok, that's 3 words ....

 

Double your engine life, improve fuel and oil consumption, lower risk of detonation and improve power.

 

There's this weird paradox'y thing going on, it's like I'm posting in the 1950's when internet wasn't even invented.

 

 

[Old Koreelah]

Your call. When and where is the moisture "boiled off"? You'd be better to have a way of pumping a bit of new oil in from a remote tank for longer trips. I've seen the mess that gets in those places where the moisture condenses. Water forms acids with most products of combustion, in pretty high concentrations. You'd have to go to over 120 degrees (well over). It would remain highly contaminated. Still need treatment with chemicals and for so small an amount not worth the risk. Nev

Nev that's why I had resisted the idea of returning recovered oil. Interesting that both CAMit and Jabiru sell recovery units.

 

 

[Old Koreelah]

If there's that much blowby the engine needs reconditioning!

You are quite right, but that will have to wait till I can get the right person to do it.

 

 

[Jaba-who]

You are quite right, but that will have to wait till I can get the right person to do it.

While in the ideal world you wouldnt return it, don't forget you are already replacing the oil every 25 hours anyway. ( jabiru rules for oil changes) and really that minuscule bit that flows back into the engine is just the same as the oil that's already in the engine ( which has pretty much the same amount of water impurities and volatiles in it as the oil that makes it into the oil condenser unit. ) In mine it would probably be less because my oil temps are always too low to burn or vapourize off much.

 

So yep while the purists would say it's got bad stuff in it and shouldn't be returned the practical reality is it's almost certainly irrelevant.

 

 

[Old Koreelah]

Both CAMit and Jabiru sell oil return units, so presumably they think that on balance, it's worth the risk.

 

Both these units are mounted to the engine so they should get hot enough to boil out the nasties.

 

However, I'm inclined to take Nev's advice and hasten slowly on this one.

 

 

[facthunter]

. The oil in the area is mixed with a lot of water as a %. In fact it's nearly all water The water is the problem. Gases percolate through it and are absorbed in the water, causing acids and bad stuff to form. This stuff is MUCK and NONE of it should be able to be reintroduced into the engine. Re the two companies doing it doesn't prove anything with me. The filler dipstick has never been satisfactory It's far too small in crosssectional area, and probably should be located in a better place where less oil will be forced out through the breather. The blow by is often excessive. Engines deteriorate much faster under these conditions. Once the chemical reactions have taken place which is happening because of the presence of WATER it's gone past the stage of just evaporating the water. You would have to re refine the new "substance" which is realistically impossible in the situation we have in the aircraft. Just dump it. These oil collector devices have been around for a long time, and most I know of have been removed or made so they just collect the stuff and it is periodically emptied. Not into the engine. Nev

 

 

[jetjr]

I bought a Jabiru one, dont think it achieved anything much.

 

An issue with Jabiru is that they tend to pump out good oil to a set level, this could be an issue on really long trips. Have to work out real oil burn which is tricky.

 

A lot of people overfill and get the perception the engine is burning the oil up.

 

CAE vent the blow off pipe to a different part to the rear of the engine.

 

An issue is maybe the small diameter of the oil fill tube and this fixes it. Now they have a catch can too. Mine uses almost no oil without this.

 

I also have on the bench a different style, and new,catch can here I could sell cheaply. Wasnt cheap to buy. Made specially for 3300.

 

Pipe with baffles inside that sits alongside coolong duct, Not required as i now have CAE engine.

 

 

[Oscar]

The CAMit return system is an oil separator and return: check it out at: Breather/Oil Separator

 

Approximately similar in operation to a gascolator. I have no idea of the Jabiru device, it may do the same.

 

Nev's point about returning water-saturated oil to the sump, is extremely important. Not only will it contain sulphuric acid due to combustion, but in extreme cases a high water content being delivered to a high-load area - e.g. the main bearings - will cause flash steam displacing the oil and causing oil starvation scavenging of the bearing surfaces. This has been observed in some Jab engines and incorrectly ascribed to tight bearing clearances.

 

 

[Old Koreelah]

The CAMit return system is an oil separator and return: check it out at: Breather/Oil Separator... I have no idea of the Jabiru device, it may do the same...

See post #6. It looks pretty simple, but not as elegant as CAMit's. Both types, being mounted to the engine, should get hot enough to prevent water condensing and returning to the engine.

 

 

[jetjr]

Theres nothing much inside the Jabiru version, i believe CAE has mesh and trapping material, bit of work gone into getting it right, like all CAE items

 

 

[facthunter]

You hope... Every motor I've worked on shows corrosion and sludge near the breather and cool parts of the engine. Having a through flow venting system is helpful but aero engines don't usually do it. By running your oil temp above 90 degrees you reduce water in oil but don't eliminate it. Once it has absorbed acids the boiling point goes way up. Don't even allow the remotest possibility of that stuff going back in. They used to put oil? breather fumes onto motorcycle chains but it ruins them and causes corrosion and the process was discontinued by most manufacturers, many years ago. I've seen mesh used and it becomes something dreadful in no time..Nev

 

 

[geoffreywh]

Moto Guzzi / Ducati and others have been returning (blowby ) oil to the sump for 50 or 60 years, I NEVER SAW any bad effects of this, Not any internal corrosion not any excessive wear. Not any acid damage, Not any water in the oil .....I think that some writers are considering what could have possibly happened or, what they think might happen or even what they think should happen....................... I know of one flat six engine (at least) with one on which returns oil to the rocker cover ( Look at oil/air separator A/C spruce) been working fine, fitted for the very same reason as the poster , for quite a few years now. With no ill effects. If the oil stays well below 100 C then I would not advise it. Not in an aircraft. Bloody Guzzi's who cares about them....NO manufacturer of ANY motorcycle blew oil from a breather on a chain and got the effect of a rusty chain. That is just fanciful.......They stopped blowing breather oil onto the chain because it made such a mess of the rear tyre. I have over 60 years experience with motorcycles and almost without exception the "breathers" (when they were in existence) were moved to the rear mudguard stay to drip their message onto the road beneath them. or to be blown onto the following blokes clothes. Sorry about the rant. I don't mean to critize other's posts. I have PMS.

 

 

[facthunter]

You are obviously directing you comments mainly at me. Let me assure you and others that it's based on actuality not dreaming or wishful thinking, or reading something somewhere. What are you saving .? A bit of sludgy oil. What are you risking? Putting severely contaminated stuff back in your motor. Have a look at any components of a crankcase PV system that's been in use for a while all the way to the air cleaner. It's never clean, and often to the point of being non functional. Every owner of a plane that I know who fitted these oil saving devices either removed it or just empties the can regularly.

 

In aviation if it's a risk why bother?

 

Some engines use a centrifugal means of separating oil from gases, or just locate the breather where it hasn't got a large amount of oil present. Not easy. Alternatively, make the breather cross section baffled at the start and larger to make the flow slower. Nev

 

 

[mnewbery]

Modern motorcycle breathers go up into the air box and this is a legislative requirement. The "modern" motorcycle engine air box has a tube going back down to ... in front of the rear tyre (actually attached to the right side of the engine or frame to avoid the tyre centre line). The tube has a bung in it which makes it impossible to vent un-burned hydrocarbons that way. Periodically, the bung is removed and the filth drained out during maintenance. Generally the tube has enough space in it so that it's not full to the top.

 

Forgetting to drain the filth away will mean eventually it will get somewhere unwelcome. But that would take years of regular riding.