how gass could get into your oil ???
11-03-03, 09:10 AM
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how gass could get into your oil ???
I was wondering how gass could get into your oil by flooding your engine? DOes it sneek past the seals and go through the holes in the eccentric shaft?
11-03-03, 09:39 AM
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ROTARYS ARE LUBRICATED INTERNALLY BY OIL, thats how they get their compression, no oil, no compression=dead motor, to much gas=less oil, no compression, no start
even in the rx-8 the dealers are trained to tell custoimers that you need to check the oil in the 8 every 2-3 tanks of gas, because rotarys consume small amounts of oil...
-greg
even in the rx-8 the dealers are trained to tell custoimers that you need to check the oil in the 8 every 2-3 tanks of gas, because rotarys consume small amounts of oil...
-greg
11-03-03, 09:52 AM
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Yes I know about that, but what I meant to ask was how does Gas get into your oil pan from flooding the engine? The Inside of the engine is compleatly sealed. The side seals on the rotors is the only place gas could leak by, and get on your eccentric shaft. If gas can get to the eccentric shaft can it get through the small holes oil is pumped through to lubricate the insides/gear side of the rotors? This is assuming oil does get pumped through the eccentric shaft (I'm not totally sure on that, but I remember being under that impression from somewhere, and there are small holes on the shaft.) If thats not the case, I don't see any way gas could get down in your oil pan.
11-03-03, 10:37 AM
#4
84SE-EGI helpy-helperton
During a flooded engine situation, gasoline can get into your oil because it is too thick in the combustion chambers, and cannot be compressed like an air/fuel mixture. This means that liquid fuel is squeezed down during the compression stroke, and the only place for it to go is past the oil control rings and into the stationary gear path and down to the inside of the rotors. This means that the fuel will be mixed with your oil, which thins the oil and destroys it's ability to transfer heat effectively.
The molecular size of gasoline is much smaller than most oils, therefore, it will pass quite easily through all associated oil systems, including the filter, the OMP, and the eccentric shaft, as you've pointed out in your second post.
The rotary engine is able to lubricate the inside of the combustion chambers through oil injection, which is fed by the Oil Metering Pump (OMP) located at the front of the engine cover. This pump is actuated by a rod attached to your throttle mechanism that increases oil flow when you step on the accellerator - in other words, the more air/gas goes in, the more oil goes in to lubricate the engine. This is the only way to get oil into the combustion chamber efficiently and effectively without having an internal engine problem like blown oil control rings, which would allow TOO MUCH oil to get into the combustion chamber.
Also, the rotary engine does pump oil through the center of the eccentric shaft which is then sprayed through nozzles onto the inner surfaces of the rotor to help cool the combustion heat along those faces. This spraying process pushes high velocity and high pressure oil against the metal, picking up the heat, and filling the rotors with oil as the engine runs. When the oil level overflows the rotor edge through sloshing as the rotor turns, it is allowed to drain down the center and side housings to the oil pan, where it is cooled further via oil cooler, filtered, and then scavenged to make the cycle again.
This method of cooling the engine is very effective, and gets the oil where it's needed. The fact that oil is being injected into the intake path is the reason why a wise rotary driver should be changing their oil frequently, and also checking oil level at every fuel filling. This is to ensure that you have good oil pressure and clean oil to the system, and that you don't run low which will significantly and quickly, cause problems. HTH,
The molecular size of gasoline is much smaller than most oils, therefore, it will pass quite easily through all associated oil systems, including the filter, the OMP, and the eccentric shaft, as you've pointed out in your second post.
The rotary engine is able to lubricate the inside of the combustion chambers through oil injection, which is fed by the Oil Metering Pump (OMP) located at the front of the engine cover. This pump is actuated by a rod attached to your throttle mechanism that increases oil flow when you step on the accellerator - in other words, the more air/gas goes in, the more oil goes in to lubricate the engine. This is the only way to get oil into the combustion chamber efficiently and effectively without having an internal engine problem like blown oil control rings, which would allow TOO MUCH oil to get into the combustion chamber.
Also, the rotary engine does pump oil through the center of the eccentric shaft which is then sprayed through nozzles onto the inner surfaces of the rotor to help cool the combustion heat along those faces. This spraying process pushes high velocity and high pressure oil against the metal, picking up the heat, and filling the rotors with oil as the engine runs. When the oil level overflows the rotor edge through sloshing as the rotor turns, it is allowed to drain down the center and side housings to the oil pan, where it is cooled further via oil cooler, filtered, and then scavenged to make the cycle again.
This method of cooling the engine is very effective, and gets the oil where it's needed. The fact that oil is being injected into the intake path is the reason why a wise rotary driver should be changing their oil frequently, and also checking oil level at every fuel filling. This is to ensure that you have good oil pressure and clean oil to the system, and that you don't run low which will significantly and quickly, cause problems. HTH,
11-03-03, 11:15 AM
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Yeah, i am having that problem currently. My car will flood if it sits for some reason. When i go to start it it takes forever to crank, and shoots a ton of fuel out the back. When i went to change the oil, the gas had thinned out my 20w50 to about 10w30....
11-29-03, 11:59 AM
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Okay, I'm waking up this thread to add something...
If the gas mixed in oil thins the oil, would that allow the thinned oil to pass through the oil seals into the combustion chambers?
My car became SERIOUSLY flooded and there is a crapload of oil in there with the fuel. The seals should be good because of the low miles on the rebuild.
If the gas mixed in oil thins the oil, would that allow the thinned oil to pass through the oil seals into the combustion chambers?
My car became SERIOUSLY flooded and there is a crapload of oil in there with the fuel. The seals should be good because of the low miles on the rebuild.
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11-29-03, 12:22 PM
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Yeah, whatever Sally......
I wouldn't even think it matters where the oil or gas is. It's just there. It's magic.
The thing that I wonder about.......is that although my car is designed to burn oil......my oil level NEVER seems to get lower.
If you run rich, does that mean you use less oil?
I wouldn't even think it matters where the oil or gas is. It's just there. It's magic.
The thing that I wonder about.......is that although my car is designed to burn oil......my oil level NEVER seems to get lower.
If you run rich, does that mean you use less oil?
11-29-03, 11:53 PM
#9
Well, seeing as how your omp puts the oil in the combustion chamber, I would check that first. There is a procedure in the haynes manual that shows you how to check the pump and tell how much it is distributing.
11-30-03, 09:37 AM
#10
The gas probably gets into the engine oil the same way the engine oil that is sent to the combustion chamber by the OMP gets back into the engine oil - it is recirculated, not burned, as is commonly assumed. I had a question about this earlier (not sure if it was answered, still digging out after Thanksgiving) but from the Atkins rotary website and from another RX7 list I read it seems clear that nearly all the oil injected into the combustion chamber recirculates back into the engine. Of course if you fill the combustion chamber full of gas because of flooding, this unburnt fuel will be recirculated into the combustion chamber along with the oil. I just love rotaries, they are so different!
Ray
Ray
11-30-03, 03:05 PM
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Alright, i found the source of my problem. Somehow my gas tank was over pressurized, and was causing extra gas to run through my carb after my car was off, causing serious flooding. Now thats fixed, and the smoke screen on startup is gone.
11-30-03, 04:29 PM
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Originally posted by ray green
The gas probably gets into the engine oil the same way the engine oil that is sent to the combustion chamber by the OMP gets back into the engine oil - it is recirculated, not burned, as is commonly assumed. I had a question about this earlier (not sure if it was answered, still digging out after Thanksgiving) but from the Atkins rotary website and from another RX7 list I read it seems clear that nearly all the oil injected into the combustion chamber recirculates back into the engine. Of course if you fill the combustion chamber full of gas because of flooding, this unburnt fuel will be recirculated into the combustion chamber along with the oil. I just love rotaries, they are so different!
Ray
The gas probably gets into the engine oil the same way the engine oil that is sent to the combustion chamber by the OMP gets back into the engine oil - it is recirculated, not burned, as is commonly assumed. I had a question about this earlier (not sure if it was answered, still digging out after Thanksgiving) but from the Atkins rotary website and from another RX7 list I read it seems clear that nearly all the oil injected into the combustion chamber recirculates back into the engine. Of course if you fill the combustion chamber full of gas because of flooding, this unburnt fuel will be recirculated into the combustion chamber along with the oil. I just love rotaries, they are so different!
Ray
The reason fuel might get into the oil is because it can sneak past the oil control o-rings or because of excessive blow-by.
12-01-03, 06:43 AM
#14
But please see LongDuck's post above, which seems to describe the same oil return system that Atkins does. There certainly seems to be a major difference of opinions on what would seem to be a fairly straight forward question. I'm starting to think I need to do some research on this question after all!
Ray
Ray
12-01-03, 10:35 AM
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Originally posted by Blitz0309
Alright, i found the source of my problem. Somehow my gas tank was over pressurized, and was causing extra gas to run through my carb after my car was off, causing serious flooding. Now thats fixed, and the smoke screen on startup is gone.
Alright, i found the source of my problem. Somehow my gas tank was over pressurized, and was causing extra gas to run through my carb after my car was off, causing serious flooding. Now thats fixed, and the smoke screen on startup is gone.
B
12-01-03, 11:33 AM
#16
That hiss is usually air being sucked in to the tank.
There's a pressure relief valve in the system that's supposed to prevent pressure build-up.
The tank is normally kept in an air-starved condition by the tank purge line so that it doesn't blow up when the wiper on the sending unit arcs.
There's a pressure relief valve in the system that's supposed to prevent pressure build-up.
The tank is normally kept in an air-starved condition by the tank purge line so that it doesn't blow up when the wiper on the sending unit arcs.
12-01-03, 12:26 PM
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It's way way way too rich inside a fuel tank with any liquid gasoline in it at all for the vapor inside to even start to ignite - "
The lower flammable limit or lower explosive limit (LFL or LEL) of gasoline is 1.4 percent; the upper flammable limit or upper explosive limit (UFL or UEL) is 7.6 percent. " Even with the cap off for a long time all you can get is a flash at the filler neck but that's it. Hollywood has it all wrong... This is not hearsay or conjecture, I'm a professional firefighter who was part of a research project some years ago to determine exactly what the hazards are regarding vehicle fuel tank flammability/explosive hazards. The only way you can one to "blow" is to fill it with a flammable mixture, i.e., between 1.4 and 7.6% vbw referred to "air" and provide an ignition source. This creates a very nasty low order explosion that will ruin your whole day and usually most of them thereafter. You will find this situation where someone will weld or grind on an old non-inerted gasoline tank that has no liquid in it. The pressure difference in respect to atmospheric that auto manufacturers create in gas tanks is purely for emissions, has nothing to do with fire/explosion prevention.
-Mike
The lower flammable limit or lower explosive limit (LFL or LEL) of gasoline is 1.4 percent; the upper flammable limit or upper explosive limit (UFL or UEL) is 7.6 percent. " Even with the cap off for a long time all you can get is a flash at the filler neck but that's it. Hollywood has it all wrong... This is not hearsay or conjecture, I'm a professional firefighter who was part of a research project some years ago to determine exactly what the hazards are regarding vehicle fuel tank flammability/explosive hazards. The only way you can one to "blow" is to fill it with a flammable mixture, i.e., between 1.4 and 7.6% vbw referred to "air" and provide an ignition source. This creates a very nasty low order explosion that will ruin your whole day and usually most of them thereafter. You will find this situation where someone will weld or grind on an old non-inerted gasoline tank that has no liquid in it. The pressure difference in respect to atmospheric that auto manufacturers create in gas tanks is purely for emissions, has nothing to do with fire/explosion prevention.
-Mike
12-01-03, 03:38 PM
#18
84SE-EGI helpy-helperton
Just to clarify on my explanation above, the oil used to cool the rotors from the INSIDE is drained down through the center and rear housings back to the oilpan for recirculation.
Oil that is INJECTED into the intake is burned and expelled out the exhaust ports. There is no way to recover this oil, and that's why rotary engines consume oil whether you have engine leaks or not - the Oil Metering Pump is actively pumping oil into the intake tract based on how much right foot you're putting into it. This ensures that the rotor side seals and tip seals are getting enough lubrication - there is no internal lubrication path for apex seals or sideseals - the oil control rings prevent oil from getting to these in a properly functioning engine!
Premix or proper OMP, any oil that's injected into the intake gets ingested and burned. No question.
Oil that is INJECTED into the intake is burned and expelled out the exhaust ports. There is no way to recover this oil, and that's why rotary engines consume oil whether you have engine leaks or not - the Oil Metering Pump is actively pumping oil into the intake tract based on how much right foot you're putting into it. This ensures that the rotor side seals and tip seals are getting enough lubrication - there is no internal lubrication path for apex seals or sideseals - the oil control rings prevent oil from getting to these in a properly functioning engine!
Premix or proper OMP, any oil that's injected into the intake gets ingested and burned. No question.
12-01-03, 03:49 PM
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12-01-03, 06:40 PM
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Originally posted by efi12a
It's way way way too rich inside a fuel tank with any liquid gasoline in it at all for the vapor inside to even start to ignite - "
The lower flammable limit or lower explosive limit (LFL or LEL) of gasoline is 1.4 percent; the upper flammable limit or upper explosive limit (UFL or UEL) is 7.6 percent. " Even with the cap off for a long time all you can get is a flash at the filler neck but that's it. Hollywood has it all wrong... This is not hearsay or conjecture, I'm a professional firefighter who was part of a research project some years ago to determine exactly what the hazards are regarding vehicle fuel tank flammability/explosive hazards. The only way you can one to "blow" is to fill it with a flammable mixture, i.e., between 1.4 and 7.6% vbw referred to "air" and provide an ignition source. This creates a very nasty low order explosion that will ruin your whole day and usually most of them thereafter. You will find this situation where someone will weld or grind on an old non-inerted gasoline tank that has no liquid in it. The pressure difference in respect to atmospheric that auto manufacturers create in gas tanks is purely for emissions, has nothing to do with fire/explosion prevention.
-Mike
It's way way way too rich inside a fuel tank with any liquid gasoline in it at all for the vapor inside to even start to ignite - "
The lower flammable limit or lower explosive limit (LFL or LEL) of gasoline is 1.4 percent; the upper flammable limit or upper explosive limit (UFL or UEL) is 7.6 percent. " Even with the cap off for a long time all you can get is a flash at the filler neck but that's it. Hollywood has it all wrong... This is not hearsay or conjecture, I'm a professional firefighter who was part of a research project some years ago to determine exactly what the hazards are regarding vehicle fuel tank flammability/explosive hazards. The only way you can one to "blow" is to fill it with a flammable mixture, i.e., between 1.4 and 7.6% vbw referred to "air" and provide an ignition source. This creates a very nasty low order explosion that will ruin your whole day and usually most of them thereafter. You will find this situation where someone will weld or grind on an old non-inerted gasoline tank that has no liquid in it. The pressure difference in respect to atmospheric that auto manufacturers create in gas tanks is purely for emissions, has nothing to do with fire/explosion prevention.
-Mike
"Nothing to do with fire/explosion prevention"?
Man, you are way out on a limb with that post.
12-01-03, 07:22 PM
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"Purely for emissions"?
"Nothing to do with fire/explosion prevention"?
Man, you are way out on a limb with that post.
Please clarify exactly why you think I'm "out on a limb".
Perhaps you're not in the US - that may explain why you're not familiar with the US EPA's edicts that volatile hydrocarbon fumes from motor vehicles' fuel tanks are not to be vented to the atmosphere - hence carbon canisters for quite some time. These absorb said HC fumes and, if the emission control systems are working correctly, these fumes are burned at an appropriate future time rather than being released.
If you don't understand the chemistry and physics regarding the flammability of gasoline in a tank, please, let's go off list, I can help you understand this. Simply put, you CANNOT initiate an "explosion" in a vehicle's fuel tank via electrical spark, if it has liquid gasoline in it for a while and is plumbed as is usual for such tanks. Excessively rich mixtures will burn just as well as excessively lean mixtures - that is, not at all.
-Mike
"Nothing to do with fire/explosion prevention"?
Man, you are way out on a limb with that post.
Please clarify exactly why you think I'm "out on a limb".
Perhaps you're not in the US - that may explain why you're not familiar with the US EPA's edicts that volatile hydrocarbon fumes from motor vehicles' fuel tanks are not to be vented to the atmosphere - hence carbon canisters for quite some time. These absorb said HC fumes and, if the emission control systems are working correctly, these fumes are burned at an appropriate future time rather than being released.
If you don't understand the chemistry and physics regarding the flammability of gasoline in a tank, please, let's go off list, I can help you understand this. Simply put, you CANNOT initiate an "explosion" in a vehicle's fuel tank via electrical spark, if it has liquid gasoline in it for a while and is plumbed as is usual for such tanks. Excessively rich mixtures will burn just as well as excessively lean mixtures - that is, not at all.
-Mike
12-03-03, 05:29 PM
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My take on it was that if the oil control rings in the rotor have gone bad you will get fuel in the oil. It would get there because of high combustion pressures and unburned fuel in the narrow "ends" of the combustion chamber. My car has this fuel in oil problem.
I am also of the opinion that anyone who thinks the oil metering pump oil gets recirculated belongs to the flat earth society! Sorry but thats my opinion.
Chris
I am also of the opinion that anyone who thinks the oil metering pump oil gets recirculated belongs to the flat earth society! Sorry but thats my opinion.
Chris
12-03-03, 06:04 PM
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Originally posted by bliffle
Lots of people have that problem on all kinds of cars. The recirculating canister up in the engine compartment gets plugged and allows tank pressure to rise. Hasn't happened to me, so I'm not sure exactly how to cure it, but diagnosis is simple: when you open the tank cap there's a pronounced hiss of escaping air.
B
Lots of people have that problem on all kinds of cars. The recirculating canister up in the engine compartment gets plugged and allows tank pressure to rise. Hasn't happened to me, so I'm not sure exactly how to cure it, but diagnosis is simple: when you open the tank cap there's a pronounced hiss of escaping air.
B