Challengine conventional wisdom
05-06-2008, 11:51 AM
#26
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On the other hand, during light loads, the oil consumption is minimal, and is comparable to many piston engines in good condition.
So then, under lighter driving conditions where 1/2 quart of engine oil is burned in 3000 miles (some I've heard have done less).
Assuming the oil is burned as an intended process of normal combustion, then that's a fuel to oil ratio of 1200:1. Not much oil in there eh?
05-06-2008, 11:58 AM
#27
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Feel free to go there if you wish
Look fellas, it was Mr Atkins who stated that the oil is mostly returned to the pan. Clealy under heavy loads, that's just not true as our oil consumption increases dramatically.
On the other hand, during light loads, the oil consumption is minimal, and is comparable to many piston engines in good condition.
So then, under lighter driving conditions where 1/2 quart of engine oil is burned in 3000 miles (some I've heard have done less).
Assuming the oil is burned as an intended process of normal combustion, then that's a fuel to oil ratio of 1200:1. Not much oil in there eh?
On the other hand, during light loads, the oil consumption is minimal, and is comparable to many piston engines in good condition.
So then, under lighter driving conditions where 1/2 quart of engine oil is burned in 3000 miles (some I've heard have done less).
Assuming the oil is burned as an intended process of normal combustion, then that's a fuel to oil ratio of 1200:1. Not much oil in there eh?
05-06-2008, 12:01 PM
#28
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Tell me then, exactly how does an engineer think and while you're at it, why not answer the poster's question as to how to install his temp control ****.
05-06-2008, 12:13 PM
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05-06-2008, 12:18 PM
#30
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My god man. Give it up. Having been an engineer for 20+ years, I'm yet to think in blue. Back on topic, where you unwittedly admitted that the challenge was a good one....and it's yet to be disproven by anything but your limited sample space.
05-06-2008, 12:34 PM
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I'm unsubscribing from this thread, 20+ year engineers who think they're going to re-invent the wheel feel free to take my place
05-06-2008, 07:29 PM
#33
"68. Does the oil in the combustion chamber burn?
Hardly any of the oil in the combustion chamber burns, it is scraped off of the cast irons by the oil rings and returned to the oil pan. "
Above is quoted from FAQ #68 on the Atkins rotary website.
Someone needs to tell Mr. Atkins they're wrong about the oil burning...argue that one with him.
"During "spirited" driving my exhaust turns a very light brown."
I've yet to see this. Nearly all tailpipes I've seen on these cars are blackened with soot to varying degrees. Interesting. Why is it that your car is different than others?
Using one of the theories proposed in this thread, you're building up carbon in your engine since it's not being seen in the exhaust pipe...as this statement might indicate
"But if the carbon produced during the high throttle/high rpm is exponentially (or should I say, disproportionately) more than the low throttle/low rpm, then that means that the carbon produced is not being carried out of the exhaust as in the high throttle/high rpm situation."
Unless of course, your exhaust pipes turn black when you're driving Miss Daisy.
Hardly any of the oil in the combustion chamber burns, it is scraped off of the cast irons by the oil rings and returned to the oil pan. "
Above is quoted from FAQ #68 on the Atkins rotary website.
Someone needs to tell Mr. Atkins they're wrong about the oil burning...argue that one with him.
"During "spirited" driving my exhaust turns a very light brown."
I've yet to see this. Nearly all tailpipes I've seen on these cars are blackened with soot to varying degrees. Interesting. Why is it that your car is different than others?
Using one of the theories proposed in this thread, you're building up carbon in your engine since it's not being seen in the exhaust pipe...as this statement might indicate
"But if the carbon produced during the high throttle/high rpm is exponentially (or should I say, disproportionately) more than the low throttle/low rpm, then that means that the carbon produced is not being carried out of the exhaust as in the high throttle/high rpm situation."
Unless of course, your exhaust pipes turn black when you're driving Miss Daisy.
Did you ever think that the AF's are such that all the fuel is getting burned? Hence no carbon choking my engine or exhaust. That would make Al Gore happy now wouldn't it. A engine properly tuned should not leave carbon behind internally.
I have lots of people including the dealer and technicians that have seen this in my exhaust.
Seems to me there is a thread that I recall about someones track time and how White the exhaust pipe was.
05-06-2008, 08:03 PM
#34
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Well, let's see. Complete combustion of a hyrdrocarbon results in carbon dioxide and water, and of course is an exothermic, in the case of gasoline, a very rapid exothermic reaction.
Additonally, under ideal conditions the A/F ratio for combustion of gasoline is 14.7:1 at standard temp and pressure Since precise temperature in the combustion chamber is not measured, and the O2 sensors have non-uniform response and are the only method of feedback into the A/F control measures, the probability of complete combustion is minimal. In addition to unburned hydrocarbons, cars produce carbon monoxide, oxides or nitrogen and other compounds in their combustion chambers. If complete combustion occurred, we wouldn't have catalytic converters, since their job in life is to produce that ideal CO2 and water exhaust. Of course you could google this stuff if your had an interest...a quick search yielded these simple chemical equations.
C(x)H(y) +O2 —›H2O + CO2
CH4 + 2O2 ---› 2 H20 + C02
So to answer your question, yes, I have thought about it.
Where the brown stuff comes from, I'm not sure. I'm sure Al Gore is full of it though.
Additonally, under ideal conditions the A/F ratio for combustion of gasoline is 14.7:1 at standard temp and pressure Since precise temperature in the combustion chamber is not measured, and the O2 sensors have non-uniform response and are the only method of feedback into the A/F control measures, the probability of complete combustion is minimal. In addition to unburned hydrocarbons, cars produce carbon monoxide, oxides or nitrogen and other compounds in their combustion chambers. If complete combustion occurred, we wouldn't have catalytic converters, since their job in life is to produce that ideal CO2 and water exhaust. Of course you could google this stuff if your had an interest...a quick search yielded these simple chemical equations.
C(x)H(y) +O2 —›H2O + CO2
CH4 + 2O2 ---› 2 H20 + C02
So to answer your question, yes, I have thought about it.
Where the brown stuff comes from, I'm not sure. I'm sure Al Gore is full of it though.
05-06-2008, 08:35 PM
#36
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Ahh, spelling. The internet and intellectual equivalent of the Curly defense. Ya! Ya! Ya!
Oh well....on to the next discussion about changing air filters, oil and spark plugs.
Oh well....on to the next discussion about changing air filters, oil and spark plugs.
05-06-2008, 11:51 PM
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05-07-2008, 01:50 AM
#39
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Over time, engine oil turns black, even in the rotary. Therefore, there definitely IS a path from the combustion chamber to the oilpan.
Still leaves open the question of how much injected oil might be able to take that path. It could be answered if someone is using an external oil tank; choose a 2-stroke oil with an additive that your sump oil doesn't contain. Then do a used oil analysis at some point and see how much of that additive finds its way into the sump oil.
Still leaves open the question of how much injected oil might be able to take that path. It could be answered if someone is using an external oil tank; choose a 2-stroke oil with an additive that your sump oil doesn't contain. Then do a used oil analysis at some point and see how much of that additive finds its way into the sump oil.
05-07-2008, 04:55 AM
#40
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I think all of you are taking a statement made by Atkins Rotary, that was made in response to a presumed question, out-of-context. I believe, judging by the response given by Atkins in #68, that the question asked had something to do with how much oil that is normally reserved for bearing lubrication/engine cooling and stored in the oil pan is burned off by normal engine operation as opposed to that which is introduced in the engine through the OMP system. In other words, if we were to disable the OMP system altogether how much oil would be burned due to passing across the oil seals, cutoff seals, etc.
If my presumption is correct I can tell you that Atkins is also correct. I lose no oil pan oil between oil changes since I have the Sohn Adapter that delivers the injection oil from an outside reservoir.
Make sense?
If my presumption is correct I can tell you that Atkins is also correct. I lose no oil pan oil between oil changes since I have the Sohn Adapter that delivers the injection oil from an outside reservoir.
Make sense?
Hello Charles,
While it may be true that the question/answer in #68 is about oil burned outside the OMP, I'm less in inclined to believe that than think it's referring specifically about the OMP since that's the source of oil being burned an why the rotary engine has the "reputation" for being an oil burner. Also, he said most of it is "scraped off" and I'm assuming he meant its scraped off instead of being burned in the combustion chamber.
The question's answer, for my stock RX8 is correct when the car is driven normally, OMP or not. Since the car consumes about 1/2 quart in 3000 miles of normal driving. MY LS1 used nearly that much.
This subject is brought up a lot, along with the carbon produced by these engines.
The conventional wisdom being challenged is:
(1) the cars engine is "cleaned" of carbon by driving it hard. I don't see Atkins stating that as a method for keeping our engines from having the carbon lock problem and in fact I observe far more carbon in the exhaust having driven it agressively vs. normally....carbon being the product of incomplete combustion of either gasoline, oil or both.
(2) The usage of the sohn oil adapter. if the questions answer was taken from the correct context, woul have to result in the
So one question I have is how much oil does the OMP deliver as a function of RPM, throttle position, and whatever other variables are used by the PCM to control the flow rate. I am assuming the OMP has direct or indirect electronic flow control only by the fact the PCM reflashes affect it.
If it could be derived to be 1200:1 at normal driving speeds for example, then at 1/2 quart and 3000 miles the oil it's delivering is in fact being burned.
But 1200:1 doesn't sound like an amount that will effectively lubricate anything.
05-07-2008, 09:08 AM
#41
Dig,
You are right about lack of lubrication---but,you may want to read a long thread on the OMP that was discussed in detail, along with possible modifications.
I think Ray is correct concerning the Adkins statement. Seems very lodgical to me.
In response to your questions
1- have you tracked your car? If you have not then you havent driven it hard -- i think that is the definition most of us except. Redlining it a couple of times a day is not driving it hard. By tracking the car(not drag racing) the engines temperature is hotter than normal, the oil temps are hotter than normal and the amount of air being pumped through the engine is maybe 100 fold. Any one that has tracked their car will tell you that the engine runs better for a while after they do. Tailpipes do run lighter on the track. The pcm is not doing any short or long time trims at the track rpms/load and the mix may become a little leaner --i really dont have evidence for that--just a thought.
But, to summerize--high temps, high air flow, high fuel flow through an engine does have a slight cleansing affect.
The rotary has a rep as an oil burner simply because it is injected into the combustion chamber --not unlike a 2 cycle engine.
Remember one thing also---all engines have some blowby----alll.
olddragger
You are right about lack of lubrication---but,you may want to read a long thread on the OMP that was discussed in detail, along with possible modifications.
I think Ray is correct concerning the Adkins statement. Seems very lodgical to me.
In response to your questions
1- have you tracked your car? If you have not then you havent driven it hard -- i think that is the definition most of us except. Redlining it a couple of times a day is not driving it hard. By tracking the car(not drag racing) the engines temperature is hotter than normal, the oil temps are hotter than normal and the amount of air being pumped through the engine is maybe 100 fold. Any one that has tracked their car will tell you that the engine runs better for a while after they do. Tailpipes do run lighter on the track. The pcm is not doing any short or long time trims at the track rpms/load and the mix may become a little leaner --i really dont have evidence for that--just a thought.
But, to summerize--high temps, high air flow, high fuel flow through an engine does have a slight cleansing affect.
The rotary has a rep as an oil burner simply because it is injected into the combustion chamber --not unlike a 2 cycle engine.
Remember one thing also---all engines have some blowby----alll.
olddragger
05-07-2008, 09:51 AM
#42
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I think all of you are taking a statement made by Atkins Rotary, that was made in response to a presumed question, out-of-context. I believe, judging by the response given by Atkins in #68, that the question asked had something to do with how much oil that is normally reserved for bearing lubrication/engine cooling and stored in the oil pan is burned off by normal engine operation as opposed to that which is introduced in the engine through the OMP system. In other words, if we were to disable the OMP system altogether how much oil would be burned due to passing across the oil seals, cutoff seals, etc.
If my presumption is correct I can tell you that Atkins is also correct. I lose no oil pan oil between oil changes since I have the Sohn Adapter that delivers the injection oil from an outside reservoir.
Make sense?
If my presumption is correct I can tell you that Atkins is also correct. I lose no oil pan oil between oil changes since I have the Sohn Adapter that delivers the injection oil from an outside reservoir.
Make sense?
Here's the question from the FAQ on their website and the answer, cut and paste style:
"68. Does the oil in the combustion chamber burn?
Hardly any of the oil in the combustion chamber burns, it is scraped off of the cast irons by the oil rings and returned to the oil pan. "
Since they say "In the combustion chamber" I assumed this meant injected oil.
05-07-2008, 10:36 AM
#43
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I see only 2 possibilities with Atkins statement. 1 is that he got confused when typing the answer. The second possibility is that the question is worded in a way that is confusing and is intended to ask something other than it implies.
If the question is "How much metered oil is burned in the combustion chamber?", then his answer is all wrong. Some of it gets burned. Some of it goes out the tailpipe and yet some more of it forms carbon deposits. The easier you drive, the less of it gets injected and less of it goes out the engine and more of it builds up inside. The harder you drive, the more that gets injected and the more that gets burned, expelled, etc. Less tends to build up inside as carbon deposits this way. All forms of driving will result in soot buildup on the tailpipes and harder driving may result in more soot on the tailpipes as more went out the exhaust.
If the original question was "How much non injected oil gets past the side seals and burned in the engine?" then his answer would be correct. Oil is sent through the rotors to cool them and this oil drains out the sides of the rotors. Since it hits the side housings in the process, the oil control rings scrape it off and send it back down to the pan. The oil hitting the side housings does not do so to lubricate anything. It's just the way it flows out of the rotors. The oil control rings are just that, control rings. They control the return flow of oil to the pan.
This all assumes that everything in the engine is doing it's job properly.
If the question is "How much metered oil is burned in the combustion chamber?", then his answer is all wrong. Some of it gets burned. Some of it goes out the tailpipe and yet some more of it forms carbon deposits. The easier you drive, the less of it gets injected and less of it goes out the engine and more of it builds up inside. The harder you drive, the more that gets injected and the more that gets burned, expelled, etc. Less tends to build up inside as carbon deposits this way. All forms of driving will result in soot buildup on the tailpipes and harder driving may result in more soot on the tailpipes as more went out the exhaust.
If the original question was "How much non injected oil gets past the side seals and burned in the engine?" then his answer would be correct. Oil is sent through the rotors to cool them and this oil drains out the sides of the rotors. Since it hits the side housings in the process, the oil control rings scrape it off and send it back down to the pan. The oil hitting the side housings does not do so to lubricate anything. It's just the way it flows out of the rotors. The oil control rings are just that, control rings. They control the return flow of oil to the pan.
This all assumes that everything in the engine is doing it's job properly.
05-07-2008, 11:33 AM
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05-07-2008, 07:47 PM
#46
and yea Ray--I do remember that! Always a search for the best premix and the right plug and keep 2 extra plugs in your pocket---especially before truely digital ignitions and ported 2 cycles with larger venturis!!
I can remember the popping.
olddragger
I can remember the popping.
olddragger
05-07-2008, 08:46 PM
#47
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Thread Starter
Dig,
You are right about lack of lubrication---but,you may want to read a long thread on the OMP that was discussed in detail, along with possible modifications.
I think Ray is correct concerning the Adkins statement. Seems very lodgical to me.
In response to your questions
1- have you tracked your car? If you have not then you havent driven it hard -- i think that is the definition most of us except. Redlining it a couple of times a day is not driving it hard. By tracking the car(not drag racing) the engines temperature is hotter than normal, the oil temps are hotter than normal and the amount of air being pumped through the engine is maybe 100 fold. Any one that has tracked their car will tell you that the engine runs better for a while after they do. Tailpipes do run lighter on the track. The pcm is not doing any short or long time trims at the track rpms/load and the mix may become a little leaner --i really dont have evidence for that--just a thought.
But, to summerize--high temps, high air flow, high fuel flow through an engine does have a slight cleansing affect.
The rotary has a rep as an oil burner simply because it is injected into the combustion chamber --not unlike a 2 cycle engine.
Remember one thing also---all engines have some blowby----alll.
olddragger
You are right about lack of lubrication---but,you may want to read a long thread on the OMP that was discussed in detail, along with possible modifications.
I think Ray is correct concerning the Adkins statement. Seems very lodgical to me.
In response to your questions
1- have you tracked your car? If you have not then you havent driven it hard -- i think that is the definition most of us except. Redlining it a couple of times a day is not driving it hard. By tracking the car(not drag racing) the engines temperature is hotter than normal, the oil temps are hotter than normal and the amount of air being pumped through the engine is maybe 100 fold. Any one that has tracked their car will tell you that the engine runs better for a while after they do. Tailpipes do run lighter on the track. The pcm is not doing any short or long time trims at the track rpms/load and the mix may become a little leaner --i really dont have evidence for that--just a thought.
But, to summerize--high temps, high air flow, high fuel flow through an engine does have a slight cleansing affect.
The rotary has a rep as an oil burner simply because it is injected into the combustion chamber --not unlike a 2 cycle engine.
Remember one thing also---all engines have some blowby----alll.
olddragger
Although I'm sure it's fun, and expensive, I don't track my car. Perhaps I should as traffic around here lives little room for actually driving it.
As for many threads on this subject, my reason for posting it here had 100% to do with what the Atkins site said which is, assuming he was referring to injected oil, is inconsistent with the advice given in many threads on this site. that advice being that the car must be redlined once a day to prevent carbon buildup and that the carbon buildup is due to incomplete combustion of the oil in the combustion chamber.
I added the fact that I know more carbon is in my exhaust pipes when I drive it hard, and more oil is burned. and combining those two might lead one to believe that driving hard does exactly the opposite of what is the advice, or conventional wisdom would have us do.
Not an unreasonable line of thinking.
Also, I am considering the Sohn for my car, but perhaps not if my motor oil will be mixed with injected 2 cycle.
05-07-2008, 08:55 PM
#48
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Thread Starter
Charles/Old Dragger/RotaryGod...
I'm simply trying to learn from those more experienced with this car than I.
There are many variables at work in these engines of course, and in combination they're pretty complex. The only way to learn about them either be involved in the engineering of such systems or having practical experience using them and I've been exposed to neither.
When I see experts, whether they be of the variety who've acquired knowledge through practical application and hands on experience, or gained in the engineering design of these engines, seemingly contradict one another, I ask questions and challenge the answers.
Long term testing under tightly contolled conditions with large sample sizes will yield outcomes that are useful to predict the behavior of these engines. I'm trying to use your communicated collective experiences in place of that.
I'm simply trying to learn from those more experienced with this car than I.
There are many variables at work in these engines of course, and in combination they're pretty complex. The only way to learn about them either be involved in the engineering of such systems or having practical experience using them and I've been exposed to neither.
When I see experts, whether they be of the variety who've acquired knowledge through practical application and hands on experience, or gained in the engineering design of these engines, seemingly contradict one another, I ask questions and challenge the answers.
Long term testing under tightly contolled conditions with large sample sizes will yield outcomes that are useful to predict the behavior of these engines. I'm trying to use your communicated collective experiences in place of that.
05-08-2008, 12:20 AM
#49
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Don't ever be scared to ask a question. Of course this also means that you shouldn't ever be surprised if you are told to search!!! 
We all learned from someone somewhere.
We all learned from someone somewhere.
05-08-2008, 09:01 AM
#50
Hey NP man---you should have seen the questions i was posting in early 2004--this being my 1st rotory engine!
Answering questions/ challanges is a hell of a lot better than playing sudoko for my old brain I am more than willing to share my rotory experiences.
This carbon issue is real and since we have a 270 degree flame front and need to run rich at times to help keep tempertures down etc--we are going to have carbon issues. We are going to have lubrication issues also. And it is not just on the rotor housing. You should see some of the eccentric front bearing wear at 50K.
There are things that can be done to help with the carbon, just as there are thing that can help with the lubrication.
With the current omp and the fuel system we now have --we are challanged.
Keep the questions coming.
olddragger
Answering questions/ challanges is a hell of a lot better than playing sudoko for my old brain
I am more than willing to share my rotory experiences.This carbon issue is real and since we have a 270 degree flame front and need to run rich at times to help keep tempertures down etc--we are going to have carbon issues. We are going to have lubrication issues also. And it is not just on the rotor housing. You should see some of the eccentric front bearing wear at 50K.
There are things that can be done to help with the carbon, just as there are thing that can help with the lubrication.
With the current omp and the fuel system we now have --we are challanged.
Keep the questions coming.
olddragger