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JohnF

Joined: 13 May 2010
Posts: 124

Posted: Sat Mar 30, 2013 11:10 am Post subject: Rotax 912ULS Oil Check

In checking the oil on the 912 via the gurgle method I usually find I have to turn the prop over around 20  times. I noticed one pilot suggested doing this right after flying...said it would be easier.



So I did that this morning....got a gurgle after perhaps three prop rotations. 

That's nice, but I wonder why? Oil was right up there, so it all was pumped into the oil tank. Hmmmmm .....

Alan Carter

Joined: 02 Jul 2012
Posts: 378
Location: Kent, England.

Posted: Sat Mar 30, 2013 12:30 pm Post subject: Re: Rotax 912ULS Oil Check

Hi John.

I am no expert,but i think you are suppose to gurgle before flying,

as it gets the oil round the bearings before the engine fires up.

I find its about 20+ turns but i find if i have not started the engine for quite some time it could be 40+ turns. i just keep pulling it over and wonder if i have missed it, but i keep going and sure enough then come the gurgle.

Alan

JohnF

Joined: 13 May 2010
Posts: 124

Posted: Sat Mar 30, 2013 12:39 pm Post subject: Re: Rotax 912ULS Oil Check

Alan,  I  don't think it makes any difference if the oil is checked before or after a flight...I just  want to know how much oil is in the engine....it won't change much after a short flight...the 912 doesn't use oil between changes.



My wonderment is why all the residual oil gets 'pumped' into the tank so easily when checked right after a flight, as opposed to before. I doubt that oil gets 'sucked' out of the tank while the plane is just sitting there...all this is just mental exercise with little real world  importance...



One pilot mentioned looking at the oil level before doing anything; then gurgle it and see the 'full' oil level. After that you could perhaps just look at the dip stick without doing anything, relying on the oil that could be pumped back to the tank.  I don't really recommend that but it could be useful info.

Alan Carter

Joined: 02 Jul 2012
Posts: 378
Location: Kent, England.

Posted: Sat Mar 30, 2013 12:59 pm Post subject: Re: Rotax 912ULS Oil Check

Hi John.

Im sure we will get an expert in on this sometime.

But the engine should be gurgled before engine start,

On big dry sump engines you pull the prop over to check there is no Hydraulicking  due to oil building up in the sump, the rotax is a dry sump and i guess the same applies, also it is important to get oil around the bearings,

But we have some experts on sit who will give a better answer,

Alan

BARRY CHECK 6

Joined: 15 Mar 2011
Posts: 738

Posted: Sat Mar 30, 2013 1:48 pm Post subject: Rotax 912ULS Oil Check

I love the way you guys throw around the term EXPERT!Do you know the definition of the word expert?

Well, if I may, let me enlighten you:

X is the algebraic symbol for an unknown.

 SPURT is a drip under pressure.

Therefore an x-spurt is an Unknown Drip Under Pressure.

Barry



On Sat, Mar 30, 2013 at 4:59 PM, Alan Carter <alancarteresq(at)onetel.net (alancarteresq(at)onetel.net)> wrote:

 [quote]--> RotaxEngines-List message posted by: "Alan Carter" <alancarteresq(at)onetel.net (alancarteresq(at)onetel.net)>

  

 Hi John.

 

Im sure we will get an expert in on this sometime.

 But the engine should be gurgled before engine start,

 On big dry sump engines you pull the prop over to check there is no Hydraulicking  due to oil building up in the sump, the rotax is a dry sump and i guess the same applies, also it is important to get oil around the bearings,

  But we have some experts on sit who will give a better answer,

 Alan

 

 

 

 

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http://forums.matronics.com/viewtopic.php?p=397346#397346

 

 

 

 

 

 

 

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[b]

Alan Carter

Joined: 02 Jul 2012
Posts: 378
Location: Kent, England.

Posted: Sat Mar 30, 2013 2:09 pm Post subject: Re: Rotax 912ULS Oil Check

Can you have an" unknown" drip under pressure, ??

Alan.

But the question is gurgle before or after ?

Roger Lee

Joined: 10 Jan 2006
Posts: 1464
Location: Tucson, Az.

Posted: Sat Mar 30, 2013 7:31 pm Post subject: Re: Rotax 912ULS Oil Check

Hi Guys,



What determines how many revolutions the prop needs to turn before the gurgle is how much oil is in the bottom of your crankcase. That is all the prop rotation is doing is building some crankcase pressure that pushes the oil in the bottom of the crankcase back to the oil tank out that bottom hose on the engine. It can change when cold and it is usually less right after flying.This level can change over time on your engine so the revolutions needed may change with it. Other things that can determine some of this is whether you are using the older verses new Rotax oil filters or some off brand. filter. The tank height in relation to the engine. Some aircraft have it mounted high and some low. The tank height has a spec in the Rotax manual which doesn't always get followed.

Can the oil level lie to you after a gurgle? Absolutely

_________________
Roger Lee
Tucson, Az.
Rotax Instructor & Rotax IRC
Light Sport Repairman
Home 520-574-1080 TRY HOME FIRST
Cell 520-349-7056

jim.kulbeth(at)insightbb.
Guest

Posted: Sat Mar 30, 2013 8:03 pm Post subject: Rotax 912ULS Oil Check

Roger I have a question. Last year I went to Florida to pickup up a plane with a 912UL in it. It had not flown for about 3 months. When we checked the oil the tank was empty. After about 10 revolutions we heard what we call the burp and turned a couple more. We checked the oil and it was good. That was my first experience with Rotax. Fast forward until now. I have a912UL and every time I fly I check the oil but do not burp the engine because the tank oil checks good on the stick. When I read my hand book it says to check the oil and either rotate the prop as discussed, or start the engine and idle for one minute.  In your opinion, am I damaging my engine if I do the latter?



Regards

Jimmy



On Mar 30, 2013, at 11:31 PM, "Roger Lee" <ssadiver1(at)yahoo.com> wrote:



 	  Quote: 	
		   

 

 Hi Guys,

 

 What determines how many revolutions the prop needs to turn before the gurgle is how much oil is in the bottom of your crankcase. That is all the prop rotation is doing is building some crankcase pressure that pushes the oil in the bottom of the crankcase back to the oil tank out that bottom hose on the engine. It can change when cold and it is usually less right after flying.This level can change over time on your engine so the revolutions needed may change with it. Other things that can determine some of this is whether you are using the older verses new Rotax oil filters or some off brand. filter. The tank height in relation to the engine. Some aircraft have it mounted high and some low. The tank height has a spec in the Rotax manual which doesn't always get followed.

 Can the oil level lie to you after a gurgle? Absolutely

 

 --------

 Roger Lee

 Tucson, Az.

 Light Sport Repairman - Maintenance Rated

 Rotax Repair Center - Heavy Maint. Rated

 Home 520-574-1080  TRY HOME FIRST

 Cell 520-349-7056

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=397388#397388

Thom Riddle

Joined: 10 Jan 2006
Posts: 1597
Location: Buffalo, NY, USA (9G0)

Posted: Sun Mar 31, 2013 4:34 am Post subject: Re: Rotax 912ULS Oil Check

Jimmy,

I am not Roger but am a powerplant mechanic with Rotax training and 10 years experience flying and maintaining Rotax 912 series engines.



You do not want to overfill the oil tank. The only way to be sure you are not overfilling is to go through burp/gurgle process. If it reads anywhere near the middle or top of the acceptable range after sitting for several hours, it might be overfilled. The only way to know is to burp it and check. I've seen owners that did not understand this and filled the tank to the top mark when cold (after sitting for long time) and that way overfilled it.



If you are certain there is sufficient oil in the tank, i.e., a good portion of the pickup tube is covered in oil, starting the engine and letting it idle will not hurt the engine. Shutting it down then checking the oil level will give you a better idea of actual oil quantity but it is not really a substitute for burping per operator's manual.

_________________
Thom Riddle
Buffalo, NY (9G0)

Don't worry about old age... it doesn't last very long.
- Anonymous

BARRY CHECK 6

Joined: 15 Mar 2011
Posts: 738

Posted: Sun Mar 31, 2013 5:54 am Post subject: Rotax 912ULS Oil Check

Alan:



I'm surprised you have to ask!  If you want to be accepted by others you should gargle every morning after you brush your teeth.  Your parent's should have taught you that!  



 

As for the engine - - It should not even be a question.  Common sense would tell you that, you should have oil coating as much of the engine workings as possible BEFORE you start the engine.  So - The determining factor is how much oil drips off the previously coated parts, during the time AFTER shutdown to BEFORE start up?  SO - HOW MUCH?  Ya don't know, do ya?   You can't see inside the engine, can ya?  So - What is the ONLY determining factor?  Duh GURGLE, Duh!  So - If ya gots duh Gurgle, ya gots duh oil.  And it should be a part of every pre-flight inspection.  But, you make the decision on how much time passes before you hit the start button.  Maybe it is just a fuel stop - Or maybe just a food stop.  Your decision.

 



Now let me throw out another crazy question:

I have noticed at local airport that experimental pilots fly more than other pilots.  That is a very good thing.  Maybe it has to do with the cost of gas or maybe they fly more for the love and fun of it.  Either way that is a good thing.  But, there will always be the neglected engine, one that sits for months without being started.

 So, what is the best procedure for starting an engine that has been sitting for months?  Whoa! - Don't be so fast to answer...  There is more to it.  Consider this:  The WORST part of starting a neglected engine is that the oil has drained off the Metal to Metal points that highly require the oil.  If the oil has drained off, there is also the possibility of rust forming.  Do you REALLY want to go through your NORMAL procedure before starting?

 



This is one Drip that has been under that pressure and developed a procedure.

Barry

On Sat, Mar 30, 2013 at 6:09 PM, Alan Carter <alancarteresq(at)onetel.net (alancarteresq(at)onetel.net)> wrote:

 [quote]--> RotaxEngines-List message posted by: "Alan Carter" <alancarteresq(at)onetel.net (alancarteresq(at)onetel.net)>

  

 Can you have an" unknown" drip under pressure, ??

 Alan.

 But the question is gurgle before or after ?

 

[b]

Roger Lee

Joined: 10 Jan 2006
Posts: 1464
Location: Tucson, Az.

Posted: Sun Mar 31, 2013 6:17 am Post subject: Re: Rotax 912ULS Oil Check

Hi Jim,



It never hurts to rotate the prop some before a start, but this engine is like a motorcycle. Do you rotate that engine before start. It's not an aircraft engine from yester-year. Too many people keep relating their experience with aircraft engines to a Rotax. It isn't even in the same ballpark and needs to be thought of and treated differently. Think more motorcycle engine and you'll be far ahead of the people that treat and compare it to Lycoming's, Continental's or air-cooled engines.



The reason the gurgle item was started a long time ago has to do with more than one item. First it can give you a more true reading. That said if it's already half way up the stick it can only go higher because it is just pushing some of the oil standing in the bottom of the crankcase back to the tank. The other and bigger reason was that the older oil filters were not as good as the one Rotax has now and because people would mount tanks too high or too low it would cause problems. Too high a mount like some Kitfox's and it might have caused the hydra-lock and too low a mount siphons oil out of the engine. One problem that rotating the prop checks for is hydra-lock. It's when the oil drained back to the cylinder because the oil tank was mounted too high and the old filters didn't stop that drain back. The new Rotax oil filters are very different now. They have a new more flexible anit drain back membrane, they now have an internal check valve that no other filter has and the by-pass pressure went from 13-16 psi to 18-22 psi which is much higher than our US oil filters set at 12-15 psi. So if you are using one of our auto filters from the US and you aren't doing yourself any favors. In the old days this wasn't true, but it is now.

Checking the oil level by prop rotation is good, but just to let you know it can lie. Some Rotax owners check their oil every flight and some before and after the flight. I haven't heard of any hydra-lock cylinder issues for a long long time and it seemed to happen with the older engine's and older filters. So if you gave it a few turns then start the engine to check the oil it wouldn't hurt anything. It would help keep the system from lying to you.



Here's the other thing. If you had a wet sump engine like a Continental, Lycoming, a car engine or a motorcycle you can over fill them with oil and possibly cause some issues depending on how over filled it is. The thing about a dry sump is you can't over fill the engine, the tank's separate. No matter what the level in the tank the engine always has the same amount of oil unless it is way too low of course. If you over fill our dry sump completely separate tank all it will do is over flow out the vent tube and make a big mess. (Been there done that) The engine will never know the difference because it doesn't care how much oil is in the SEPARATE tank. The oil pump only pumps so much oil at a given rate and it doesn't care about how much volume is in the tank. It pumps at that rate no matter what.



If I fly often I check the oil level on the stick and even turn the prop over a few times, but I don't get hung up on the oil level so long as it's up on the stick at least half way before the first start of the day.

_________________
Roger Lee
Tucson, Az.
Rotax Instructor & Rotax IRC
Light Sport Repairman
Home 520-574-1080 TRY HOME FIRST
Cell 520-349-7056

henryroden

Joined: 09 Jan 2006
Posts: 13
Location: Albuquerque

Posted: Sun Mar 31, 2013 6:58 am Post subject: Re: Rotax 912ULS Oil Check

Roger's post regarding the oil tank being separate from the the engine is the most logical thing to consider. The engine does not know or care how much oil is in the tank unless it is really low. But being new to the Rotax why is it necessary to turn the the prop/engine over by hand at all before starting?

Why not use the starter with the ignitions turned off? The amount of oil left on the internal parts is the same either way, using the starter turns the engine over a little faster. This procedure would not let one discover if there was a hydraulic lock problem but it sounds like that those are very rare now with the improved oil filter. Not at all like the problems with the older radials and rotarys.

BARRY CHECK 6

Joined: 15 Mar 2011
Posts: 738

Posted: Sun Mar 31, 2013 8:13 am Post subject: Rotax 912ULS Oil Check

Roger:



A few corrections:

HYDRO - not Hydra.  Hydra is the seven headed mythical creature that Hercules slew.  

Lycoming and Continental engines DO NOT have a WET SUMP.  They have a dry sump, cars do have a wet sump.  A wet sump is one where the Crankshaft sits IN the oil, either partially or completely.  This is not so for the Lycoming or Continental... Mater of fact, the Lycoming has a baffling between the crank and oil - not a totally sealed baffle but one that is about an 80% sealed.

 

When you say: "they now have an internal check valve that no other filter has", what do you mean by that?  Champion, Tempest and ADC, ALL have check valves.  The reason for having check valves in an oil filter, especially these oil filters is: That the filter mounts high on the engine and without a check valve the oil would drain back into the engine sump and the engine would suffer oil reduction/starvation while starting and while building up pressure and flow.  This is not a good thing.  

 



By-Pass - - What is Rotax's definition of By-Pass?  On other engines it is the MINIMUM amount of oil pressure needed to OPEN the oil flow in the positive flow direction.  So, why would you want to INCREASE the pressure required?  It sounds like the check valve is set too high in pressure, so you also have a high by-pass pressure.  It only has to work against gravity.  OR Rotax's oil pump is not configured correctly to positively produce a pressure in only ONE direction.  

 



Why do you make the statement: "So if you are using one of our auto filters from the US and you aren't doing yourself any favors. In the old days this wasn't true, but it is now."  Why isn't it true now?  It sounds like there is a question in definitions?

 



Back to Dry Sumps - Your statement becomes very misleading because of its inaccuracy.  "If you had a wet sump engine like a Continental, Lycoming, a car engine or a motorcycle you can over fill them with oil and possibly cause some issues depending on how over filled it is."  By the way a Dry Sump does not mean the oil tank is 'seperate", it only means the crank is not in the direct contact to the oil in the sump.  Lycoming & Continental are DRY SUMPS.  And you surly can OVER FILL a Lycoming & Continental.  BUT!  The difference is both these engines have a BREATHER TUBE, which is connected directly to the inside of the engine, there are NO check-valves or anti-siphoning systems.  So any excess oil is simply BLOWN OUT the Breather Tube.  The only damage that is done is, the Belly of your plane becomes very dirty and you have managed to Gouge out some more money from your wallet.  Roger, you will have to comment on what damage is done to a Rotax engine if over filled.  It would be interesting to see a FLOW DIAGRAM of how a Rotax handles oil and fuel.

 



Extra Oil - If one want to add a separate oil storage tank it should be added on the return side of the oil flow. And this is dependent on where the oil feed back into the engine.  On experimental planes that wish larger oil capacity this is done by:  Adding a lower tank and connecting it to & from the sump <-- not the best, this has a flow problem.  By adding a larger oil cooler <-- Very good as it also adds to the cooling, it is easier to heat an engine than to cool an engine.  Larger and Multiple oil filters.  <-- A bit of over kill.  But the question is why one would need extra oil?  Only thing I can think of is the FAA reg, but that refers to certified engines.

 



Barry



On Sun, Mar 31, 2013 at 10:17 AM, Roger Lee <ssadiver1(at)yahoo.com (ssadiver1(at)yahoo.com)> wrote:

 [quote]--> RotaxEngines-List message posted by: "Roger Lee" <ssadiver1(at)yahoo.com (ssadiver1(at)yahoo.com)>

  

 Hi Jim,

 

 The reason the gurgle item was started a long time ago has to do with more than one item. First it can give you a more true reading. That said if it's already half way up the stick it can only go higher because it is just pushing some of the oil standing in the bottom of the crankcase back to the tank. The other and bigger reason was that the older oil filters were not as good as the one Rotax has now and because people would mount tanks too high or too low it would cause problems. Too high a mount like some Kitfox's and it might have caused the hydra-lock and too low a mount siphons oil out of the engine. One problem that rotating the prop checks for is hydra-lock. It's when the oil drained back to the cylinder because the oil tank was mounted too high and the old filters didn't stop that drain back. The new Rotax oil filters are very different now. They have a new more flexible anit drain back membrane, they now have an internal check valve that no other filter has and the!

    by-pass pressure went from 13-16 psi to 18-22 psi which is much higher than our US oil filters set at 12-15 psi. So if you are using one of our auto filters from the US and you aren't doing yourself any favors. In the old days this wasn't true, but it is now.

  Checking the oil level by prop rotation is good, but just to let you know it can lie. Some Rotax owners check their oil every flight and some before and after the flight. I haven't heard of any hydra-lock cylinder issues for a long long time and it seemed to happen with the older engine's and older filters. So if you gave it a few turns then start the engine to check the oil it wouldn't hurt anything. It would help keep the system from lying to you.

  

 Here's the other thing. If you had a wet sump engine like a Continental, Lycoming, a car engine or a motorcycle you can over fill them with oil and possibly cause some issues depending on how over filled it is. The thing about a dry sump is you can't over fill the engine, the tank's separate. No matter what the level in the tank the engine always has the same amount of oil unless it is way too low of course. If you over fill our dry sump completely separate tank all it will do is over flow out the vent tube and make a big mess. (Been there done that) The engine will never know the difference because it doesn't care how much oil is in the SEPARATE tank. The oil pump only pumps so much oil at a given rate and it doesn't care about how much volume is in the tank. It pumps at that rate no matter what.

  

 --------

 Roger Lee

[b]

Roger Lee

Joined: 10 Jan 2006
Posts: 1464
Location: Tucson, Az.

Posted: Sun Mar 31, 2013 9:10 am Post subject: Re: Rotax 912ULS Oil Check

Hi Barry,



Sorry for my typo spelling for hydra and hydro. For the sake of this debate and the Rotax,  a wet sump is where the oil reserve is held within the engine and not a separate tank out side the engine. Remember I had cars and motorcycles in there too. It isn't in the engine case. That's the most common conception for most people delineating between wet and dry sump in a Rotax conversation. It isn't worth splitting hairs because many won't know the difference as you are pointing out.  Most all filters have an anti drain back membrane (actually some really poor ones don't) and is what you are calling a check valve (kind of like Hydra and Hydro), but it isn't a real check valve, just a membrane. Look in the Rotax filer next time and you'll see the check valve down in the middle and the anti drain back membrane around the edges of the holes, but no check valve in an automotive filter.  Even the membrane was changed to be better and more flexible than most of the automotive filters. It was put there because of all the different ways owners were mounting their oil tanks. It's just an added protection feature. I guess you could say it protects the engine from owners. 

The bypass pressure was increased because they thought the by-pass mechanism, which isn't that accurate to start with (it's an emergency flow by pass only), was opening to often on start up allowing unfiltered oil to flow to the engine. The by-pass mechanism operates on a pressure differential between the up and down stream oil flow/pressure.



My comments between Rotax, Continental's and Lycoming's is to try and get people away from maintenance comparisons. The Rotax is totally different in it's materials, design and workings.

Oil and fuel flow diagrams are published and some are in the Rotax manuals. 



Once upon a time Rotax had equals in automotive filters you could buy across the counter, but that day has passed and I once thought that way, but after extensive research I now know different.

_________________
Roger Lee
Tucson, Az.
Rotax Instructor & Rotax IRC
Light Sport Repairman
Home 520-574-1080 TRY HOME FIRST
Cell 520-349-7056

Alan Carter

Joined: 02 Jul 2012
Posts: 378
Location: Kent, England.

Posted: Sun Mar 31, 2013 1:16 pm Post subject: Re: Rotax 912ULS Oil Check

Hi Chaps.

Roger that,s sounds a good explanation many thanks. I pull to prop over and it does not hurt me at 66. 

I have gurgled and filled to the top mark, and had oil all over the underside of the plane,

I always top up now to keep it about a 1/4 " down the stick now and have not had the problem again.

As for Starting and Stopping to check, I personally don,t like this idea as its another start, I like to keep my starts as low as possible, Another cycle logged in the book, a possible kick back, and on a 914 waiting for the temps to stabilizes, ete,ete, so to be easier on the plane and save my pocket i would rather but in a bit of muscle, just my choice.



Alan

jim.kulbeth(at)insightbb.
Guest

Posted: Sun Mar 31, 2013 4:04 pm Post subject: Rotax 912ULS Oil Check

Thanks,  my engine is a late model. Made in 2008. I use the Rotax filter. Hate to pay $19 bucks for a filter but guess it is worth it. I have not been burping my engine because when I check it is always half full. However mine burps quickly and being safe far outweighs sorry. 



Jimmy Kulbeth



On Mar 31, 2013, at 11:12, FLYaDIVE <flyadive(at)gmail.com (flyadive(at)gmail.com)> wrote:

[quote]Roger:



A few corrections:

HYDRO - not Hydra.  Hydra is the seven headed mythical creature that Hercules slew.  

Lycoming and Continental engines DO NOT have a WET SUMP.  They have a dry sump, cars do have a wet sump.  A wet sump is one where the Crankshaft sits IN the oil, either partially or completely.  This is not so for the Lycoming or Continental... Mater of fact, the Lycoming has a baffling between the crank and oil - not a totally sealed baffle but one that is about an 80% sealed.

 

When you say: "they now have an internal check valve that no other filter has", what do you mean by that?  Champion, Tempest and ADC, ALL have check valves.  The reason for having check valves in an oil filter, especially these oil filters is: That the filter mounts high on the engine and without a check valve the oil would drain back into the engine sump and the engine would suffer oil reduction/starvation while starting and while building up pressure and flow.  This is not a good thing.  

 



By-Pass - - What is Rotax's definition of By-Pass?  On other engines it is the MINIMUM amount of oil pressure needed to OPEN the oil flow in the positive flow direction.  So, why would you want to INCREASE the pressure required?  It sounds like the check valve is set too high in pressure, so you also have a high by-pass pressure.  It only has to work against gravity.  OR Rotax's oil pump is not configured correctly to positively produce a pressure in only ONE direction.  

 



Why do you make the statement: "So if you are using one of our auto filters from the US and you aren't doing yourself any favors. In the old days this wasn't true, but it is now."  Why isn't it true now?  It sounds like there is a question in definitions?

 



Back to Dry Sumps - Your statement becomes very misleading because of its inaccuracy.  "If you had a wet sump engine like a Continental, Lycoming, a car engine or a motorcycle you can over fill them with oil and possibly cause some issues depending on how over filled it is."  By the way a Dry Sump does not mean the oil tank is 'seperate", it only means the crank is not in the direct contact to the oil in the sump.  Lycoming & Continental are DRY SUMPS.  And you surly can OVER FILL a Lycoming & Continental.  BUT!  The difference is both these engines have a BREATHER TUBE, which is connected directly to the inside of the engine, there are NO check-valves or anti-siphoning systems.  So any excess oil is simply BLOWN OUT the Breather Tube.  The only damage that is done is, the Belly of your plane becomes very dirty and you have managed to Gouge out some more money from your wallet.  Roger, you will have to comment on what damage is done to a Rotax engine if over filled.  It would be interesting to see a FLOW DIAGRAM of how a Rotax handles oil and fuel.

 



Extra Oil - If one want to add a separate oil storage tank it should be added on the return side of the oil flow. And this is dependent on where the oil feed back into the engine.  On experimental planes that wish larger oil capacity this is done by:  Adding a lower tank and connecting it to & from the sump <-- not the best, this has a flow problem.  By adding a larger oil cooler <-- Very good as it also adds to the cooling, it is easier to heat an engine than to cool an engine.  Larger and Multiple oil filters.  <-- A bit of over kill.  But the question is why one would need extra oil?  Only thing I can think of is the FAA reg, but that refers to certified engines.

 



Barry



On Sun, Mar 31, 2013 at 10:17 AM, Roger Lee <ssadiver1(at)yahoo.com (ssadiver1(at)yahoo.com)> wrote:

  	  Quote: 	
		  --> RotaxEngines-List message posted by: "Roger Lee" <ssadiver1(at)yahoo.com (ssadiver1(at)yahoo.com)>

  

 Hi Jim,

 

 The reason the gurgle item was started a long time ago has to do with more than one item. First it can give you a more true reading. That said if it's already half way up the stick it can only go higher because it is just pushing some of the oil standing in the bottom of the crankcase back to the tank. The other and bigger reason was that the older oil filters were not as good as the one Rotax has now and because people would mount tanks too high or too low it would cause problems. Too high a mount like some Kitfox's and it might have caused the hydra-lock and too low a mount siphons oil out of the engine. One problem that rotating the prop checks for is hydra-lock. It's when the oil drained back to the cylinder because the oil tank was mounted too high and the old filters didn't stop that drain back. The new Rotax oil filters are very different now. They have a new more flexible anit drain back membrane, they now have an internal check valve that no other filter has and the!

    by-pass pressure went from 13-16 psi to 18-22 psi which is much higher than our US oil filters set at 12-15 psi. So if you are using one of our auto filters from the US and you aren't doing yourself any favors. In the old days this wasn't true, but it is now.

  Checking the oil level by prop rotation is good, but just to let you know it can lie. Some Rotax owners check their oil every flight and some before and after the flight. I haven't heard of any hydra-lock cylinder issues for a long long time and it seemed to happen with the older engine's and older filters. So if you gave it a few turns then start the engine to check the oil it wouldn't hurt anything. It would help keep the system from lying to you.

  

 Here's the other thing. If you had a wet sump engine like a Continental, Lycoming, a car engine or a motorcycle you can over fill them with oil and possibly cause some issues depending on how over filled it is. The thing about a dry sump is you can't over fill the engine, the tank's separate. No matter what the level in the tank the engine always has the same amount of oil unless it is way too low of course. If you over fill our dry sump completely separate tank all it will do is over flow out the vent tube and make a big mess. (Been there done that) The engine will never know the difference because it doesn't care how much oil is in the SEPARATE tank. The oil pump only pumps so much oil at a given rate and it doesn't care about how much volume is in the tank. It pumps at that rate no matter what.

  

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 Roger Lee





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jim.kulbeth(at)insightbb.
Guest

Posted: Sun Mar 31, 2013 4:05 pm Post subject: Rotax 912ULS Oil Check

Thanks. I plan to burp in the future. 



Jimmy Kulbeth

On Mar 31, 2013, at 7:34, "Thom Riddle" <riddletr(at)gmail.com> wrote:



 	  Quote: 	
		   

 

 Jimmy,

 I am not Roger but am a powerplant mechanic with Rotax training and 10 years experience flying and maintaining Rotax 912 series engines.

 

 You do not want to overfill the oil tank. The only way to be sure you are not overfilling is to go through burp/gurgle process. If it reads anywhere near the middle or top of the acceptable range after sitting for several hours, it might be overfilled. The only way to know is to burp it and check. I've seen owners that did not understand this and filled the tank to the top mark when cold (after sitting for long time) and that way overfilled it.

 

 If you are certain there is sufficient oil in the tank, i.e., a good portion of the pickup tube is covered in oil, starting the engine and letting it idle will not hurt the engine. Shutting it down then checking the oil level will give you a better idea of actual oil quantity but it is not really a substitute for burping per operator's manual.

 

 --------

 Thom Riddle

 Buffalo, NY (9G0)

 

 Kolb Slingshot SS-021

 no engine 

 FOR SALE

 

 Diamond Katana DA20-A1

 Rotax 912 F3

 

 Don't worry about old age... it doesn't last very long. 

 - Anonymous

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=397400#397400

jim.kulbeth(at)insightbb.
Guest

Posted: Sun Mar 31, 2013 4:23 pm Post subject: Rotax 912ULS Oil Check

Well burp, gurgle, burgle I am in.  However my planes do not sit long enough for the oil to drip off. A really good oil holds on for a while. I will not let an engine sit for a long period even in the winter. 



Jimmy Kulbeth



On Mar 31, 2013, at 8:53, FLYaDIVE <flyadive(at)gmail.com (flyadive(at)gmail.com)> wrote:

[quote]Alan:



I'm surprised you have to ask!  If you want to be accepted by others you should gargle every morning after you brush your teeth.  Your parent's should have taught you that!  



 

As for the engine - - It should not even be a question.  Common sense would tell you that, you should have oil coating as much of the engine workings as possible BEFORE you start the engine.  So - The determining factor is how much oil drips off the previously coated parts, during the time AFTER shutdown to BEFORE start up?  SO - HOW MUCH?  Ya don't know, do ya?   You can't see inside the engine, can ya?  So - What is the ONLY determining factor?  Duh GURGLE, Duh!  So - If ya gots duh Gurgle, ya gots duh oil.  And it should be a part of every pre-flight inspection.  But, you make the decision on how much time passes before you hit the start button.  Maybe it is just a fuel stop - Or maybe just a food stop.  Your decision.

 



Now let me throw out another crazy question:

I have noticed at local airport that experimental pilots fly more than other pilots.  That is a very good thing.  Maybe it has to do with the cost of gas or maybe they fly more for the love and fun of it.  Either way that is a good thing.  But, there will always be the neglected engine, one that sits for months without being started.

 So, what is the best procedure for starting an engine that has been sitting for months?  Whoa! - Don't be so fast to answer...  There is more to it.  Consider this:  The WORST part of starting a neglected engine is that the oil has drained off the Metal to Metal points that highly require the oil.  If the oil has drained off, there is also the possibility of rust forming.  Do you REALLY want to go through your NORMAL procedure before starting?

 



This is one Drip that has been under that pressure and developed a procedure.

Barry

On Sat, Mar 30, 2013 at 6:09 PM, Alan Carter <alancarteresq(at)onetel.net (alancarteresq(at)onetel.net)> wrote:

  	  Quote: 	
		  --> RotaxEngines-List message posted by: "Alan Carter" <alancarteresq(at)onetel.net (alancarteresq(at)onetel.net)>

  

 Can you have an" unknown" drip under pressure, ??

 Alan.

 But the question is gurgle before or after ?

 



	


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