Tapered-Bore Engine Break-in - Upgraded
09-04-2011, 02:26 AM
#376
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RE: Tapered-Bore Engine Break-in - Upgraded
[quote]ORIGINAL:
An example? In a two-stroke glow engine; like those discussed in this thread, the piston out-side is cooled by the cylinder fins, to which heat is transferred through the very thin oil-film of oil between them, to the sleeve and then to the cylinder casing which bears the fins. Again, the very thin oil-film of oil, about one thousandth on an inch thick, just transfers the heat; not carries it out with it.
The bottom and inside of the piston is cooled by the fresh fuel mixture, mainly through evaporation of the methanol component in the fuel.
An example? In a two-stroke glow engine; like those discussed in this thread, the piston out-side is cooled by the cylinder fins, to which heat is transferred through the very thin oil-film of oil between them, to the sleeve and then to the cylinder casing which bears the fins. Again, the very thin oil-film of oil, about one thousandth on an inch thick, just transfers the heat; not carries it out with it.
The bottom and inside of the piston is cooled by the fresh fuel mixture, mainly through evaporation of the methanol component in the fuel.
09-04-2011, 07:28 AM
#377
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RE: Tapered-Bore Engine Break-in - Upgraded
ORIGINAL: DarZeelon
Of-course, 378.
But it still is the major contributor to cooling...
Oil does very little.
In any internal combustion engine, the fuel's main job is to burn and to provide power.
The engine's job is to make power from the fuel. Heat is just a useless product that is necessary to remove, both by airflow on the cylinder fins and by the latent heat of evaporation of the fuel's components.
The oil? Its job is lubrication.
Of-course, 378.
But it still is the major contributor to cooling...
Oil does very little.
In any internal combustion engine, the fuel's main job is to burn and to provide power.
The engine's job is to make power from the fuel. Heat is just a useless product that is necessary to remove, both by airflow on the cylinder fins and by the latent heat of evaporation of the fuel's components.
The oil? Its job is lubrication.
Hey Dar, I may have all this wrong. The piston is pushed down by a force. The force is from the expanding air trapped above the piston. The air is expanding due to the massive temperature increase. The temp increase is caused by the burning of the fuel. If this is true, then the heat is the needed product to make the piston go down. So, does the energy in fuel itself do the work, expanding air due to heat, a combination of the two, something else?
Oil content? The car guys use less and there engines are run harder. Are we airplane guys ungrounded in engine tuning or is there another reason for more oil in our plane fuel? Never did understan this.
Thanks, MikeB
09-04-2011, 07:31 AM
#378
RE: Tapered-Bore Engine Break-in - Upgraded
ORIGINAL: DarZeelon
Mr Cox,
When you reply in a thread, it is advisable to first read through the posts to fully understand what is being discussed.
In post #337 Brian mentioned, toward the end of it, an engine with an iron piston running in a steel sleeve.
This is what the sentence you quoted relates to and it is definitely not a tapered-bore engine.
Mr Cox,
When you reply in a thread, it is advisable to first read through the posts to fully understand what is being discussed.
In post #337 Brian mentioned, toward the end of it, an engine with an iron piston running in a steel sleeve.
This is what the sentence you quoted relates to and it is definitely not a tapered-bore engine.
The fact that, once I got the engine to start, it behaved perfectly normally with no trace of strain proved (to my satisfaction at least) that hydrodynamic and hydrostatic pressures kept it from destroying itself.
09-04-2011, 09:16 AM
#379
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RE: Tapered-Bore Engine Break-in - Upgraded
ORIGINAL: WMB
Hey Dar, I may have all this wrong. The piston is pushed down by a force. The force is from the expanding air trapped above the piston. The air is expanding due to the massive temperature increase. The temp increase is caused by the burning of the fuel. If this is true, then the heat is the needed product to make the piston go down. So, does the energy in fuel itself do the work, expanding air due to heat, a combination of the two, something else?
Oil content? The car guys use less and there engines are run harder. Are we airplane guys ungrounded in engine tuning or is there another reason for more oil in our plane fuel? Never did understand this.
Thanks, MikeB
Hey Dar, I may have all this wrong. The piston is pushed down by a force. The force is from the expanding air trapped above the piston. The air is expanding due to the massive temperature increase. The temp increase is caused by the burning of the fuel. If this is true, then the heat is the needed product to make the piston go down. So, does the energy in fuel itself do the work, expanding air due to heat, a combination of the two, something else?
Oil content? The car guys use less and there engines are run harder. Are we airplane guys ungrounded in engine tuning or is there another reason for more oil in our plane fuel? Never did understand this.
Thanks, MikeB
It is through heat (and expansion) that an engine makes its power, but it is only between 20% and 26% of that heat; that is actually used by the engine to spin the prop.
The remainder of that heat is just excess that the engine needs to get rid of...
Getting rid of the heat is apparently not the reason plane engines need more oil.
After all, gas guys easily get away with just 2-3%, or even less.
Brian,
Because I also sometimes err in this, i.e. not reading entire posts, I can comment to others that do....
Aren't most iron-steel engines built with a parallel sleeve? I supposed this before hand.
09-04-2011, 09:19 AM
#381
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Thread Starter
RE: Tapered-Bore Engine Break-in - Upgraded
ORIGINAL: WMB
Hey Dar, I may have all this wrong. The piston is pushed down by a force. The force is from the expanding air trapped above the piston. The air is expanding due to the massive temperature increase. The temp increase is caused by the burning of the fuel. If this is true, then the heat is the needed product to make the piston go down. So, does the energy in fuel itself do the work, expanding air due to heat, a combination of the two, something else?
Oil content? The car guys use less and there engines are run harder. Are we airplane guys ungrounded in engine tuning or is there another reason for more oil in our plane fuel? Never did understand this.
Thanks, MikeB
Hey Dar, I may have all this wrong. The piston is pushed down by a force. The force is from the expanding air trapped above the piston. The air is expanding due to the massive temperature increase. The temp increase is caused by the burning of the fuel. If this is true, then the heat is the needed product to make the piston go down. So, does the energy in fuel itself do the work, expanding air due to heat, a combination of the two, something else?
Oil content? The car guys use less and there engines are run harder. Are we airplane guys ungrounded in engine tuning or is there another reason for more oil in our plane fuel? Never did understand this.
Thanks, MikeB
It is through heat (and expansion) that an engine makes its power, but it is only between 20% and 26% of that heat; that is actually used by the engine to spin the prop.
The remainder of that heat is just excess that the engine needs to get rid of...
Getting rid of the heat is apparently not the reason plane engines need more oil.
After all, gas guys easily get away with just 2-3%, or even less.
Brian,
Because I also sometimes err in this, i.e. not reading entire posts, I can comment to others that do....
Aren't most iron-steel engines built with a parallel sleeve? I supposed this before hand.
09-04-2011, 09:41 AM
#382
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RE: Tapered-Bore Engine Break-in - Upgraded
DarZeelon,
I thank you for your knowledge and willingness to endure the sarcasm and slander offered by those "experts" that oppose your view, for no good deed goes undpunished. There is nothing difficult or magical about the technique you have collated and presented here. I, for one choose to follow your advise. Others, of course, are free to choose their own path.
This forum seems to be diseased. Many, many, threads evolve into animosity. I have not seen this level of behavior on most of the forums in which I have participated. You must have been aware of the liklihood you would have to defend your original post. Thank you for continuing to support your position while at the same time not lowering your behavior to that of others.
Whenever I see a post from you I eagerly read it and know that I wll not be fuming with rage when finished.
Dick
I thank you for your knowledge and willingness to endure the sarcasm and slander offered by those "experts" that oppose your view, for no good deed goes undpunished. There is nothing difficult or magical about the technique you have collated and presented here. I, for one choose to follow your advise. Others, of course, are free to choose their own path.
This forum seems to be diseased. Many, many, threads evolve into animosity. I have not seen this level of behavior on most of the forums in which I have participated. You must have been aware of the liklihood you would have to defend your original post. Thank you for continuing to support your position while at the same time not lowering your behavior to that of others.
Whenever I see a post from you I eagerly read it and know that I wll not be fuming with rage when finished.
Dick
09-04-2011, 10:23 AM
#383
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RE: Tapered-Bore Engine Break-in - Upgraded
ORIGINAL: pilotchute
DarZeelon,
I thank you for your knowledge and willingness to endure the sarcasm and slander offered by those ''experts'' that oppose your view, for no good deed goes undpunished. There is nothing difficult or magical about the technique you have collated and presented here. I, for one choose to follow your advise. Others, of course, are free to choose their own path.
This forum seems to be diseased. Many, many, threads evolve into animosity. I have not seen this level of behavior on most of the forums in which I have participated. You must have been aware of the liklihood you would have to defend your original post. Thank you for continuing to support your position while at the same time not lowering your behavior to that of others.
Whenever I see a post from you I eagerly read it and know that I wll not be fuming with rage when finished.
Dick
DarZeelon,
I thank you for your knowledge and willingness to endure the sarcasm and slander offered by those ''experts'' that oppose your view, for no good deed goes undpunished. There is nothing difficult or magical about the technique you have collated and presented here. I, for one choose to follow your advise. Others, of course, are free to choose their own path.
This forum seems to be diseased. Many, many, threads evolve into animosity. I have not seen this level of behavior on most of the forums in which I have participated. You must have been aware of the liklihood you would have to defend your original post. Thank you for continuing to support your position while at the same time not lowering your behavior to that of others.
Whenever I see a post from you I eagerly read it and know that I wll not be fuming with rage when finished.
Dick
09-04-2011, 10:29 AM
#384
RE: Tapered-Bore Engine Break-in - Upgraded
ORIGINAL: WMB
Oil content? The car guys use less and there engines are run harder. Are we airplane guys ungrounded in engine tuning or is there another reason for more oil in our plane fuel? Never did understan this.
Thanks, MikeB
Oil content? The car guys use less and there engines are run harder. Are we airplane guys ungrounded in engine tuning or is there another reason for more oil in our plane fuel? Never did understan this.
Thanks, MikeB
My understanding is that it's because we idle our engines far more than we have them screaming, whereas aircraft engines are always roaring along at partial throttle. So having a high oil content can cause our engines to bog down, load up, flood, cut out and other assorted shenanigans. Also, we have near 0 load on ours at idle, aircraft engines have a constant load. It may also have something to do with cars needing much crisper throttle response. All that oil in the fuel tends to bog the motor down and make it want to load up, saps power too.
There may also be something to us running an air filter, so we don't need the oil to handle the dirt that gets sucked in, but that may not be the case.
09-04-2011, 10:49 AM
#385
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RE: Tapered-Bore Engine Break-in - Upgraded
Dick and Mike,
Thank you for your support.
The Israeli forum that I participate in, also has some people who very loudly demonstrate their disagreement, with some of the things I write.
I sometimes need to work very hard to prove them wrong.
So, it is not specific to this forum...
Some of those that openly disagree with me, are very knowledgeable persons.
I would like a chance to meet some day with Brian Hampton, for instance...
I am quite sure it will not turn into a fist-fight.
I quite often, also in the local forum, quote material that he wrote and I respect him.
But I disagree with some things that he writes, when I know I am right.
Thank you for your support.
The Israeli forum that I participate in, also has some people who very loudly demonstrate their disagreement, with some of the things I write.
I sometimes need to work very hard to prove them wrong.
So, it is not specific to this forum...
Some of those that openly disagree with me, are very knowledgeable persons.
I would like a chance to meet some day with Brian Hampton, for instance...
I am quite sure it will not turn into a fist-fight.
I quite often, also in the local forum, quote material that he wrote and I respect him.
But I disagree with some things that he writes, when I know I am right.
09-04-2011, 01:57 PM
#386
RE: [Deleted]
Okay, the complaints are mounting as to the tone and arguing that it taking place here. A couple of posts have been edited for the worst of it. It's hard to stay hands off of what people post when this nonsense goes on and on and on and on and on....
Bottom line, this is supposed to be fun and inviting to ALL members, regardless of experience levels. Everyone should feel totally free to post and not cringe if they had a typo, or a different procedure, or just whatever.
The sniping and any other nonsense needs to stop here. No last words, parting shots, etc please.
Bottom line, this is supposed to be fun and inviting to ALL members, regardless of experience levels. Everyone should feel totally free to post and not cringe if they had a typo, or a different procedure, or just whatever.
The sniping and any other nonsense needs to stop here. No last words, parting shots, etc please.
09-04-2011, 02:07 PM
#387
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RE: [Deleted]
Barry, there seems to be three solid camps here, the misinformed, the uninformed and the self informed and in 358 posts not one soul has changed camps. I was sorry to see this thing come back to life. The ones who read their engines instructions are the most informed.
09-04-2011, 02:42 PM
#388
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RE: [Deleted]
ORIGINAL: Hobbsy
The ones who read their engines instructions are the most informed.
The ones who read their engines instructions are the most informed.
09-04-2011, 05:47 PM
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RE: Tapered-Bore Engine Break-in - Upgraded
ORIGINAL: DarZeelon
Getting rid of the heat is apparently not the reason plane engines need more oil.
After all, gas guys easily get away with just 2-3%, or even less.
Getting rid of the heat is apparently not the reason plane engines need more oil.
After all, gas guys easily get away with just 2-3%, or even less.
ORIGINAL: DarZeelon
Aren't most iron-steel engines built with a parallel sleeve? I supposed this before hand.
Aren't most iron-steel engines built with a parallel sleeve? I supposed this before hand.
Cheers mate
09-04-2011, 06:15 PM
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RE: [Deleted]
ORIGINAL: Hobbsy
................ and in 358 posts not one soul has changed camps.
................ and in 358 posts not one soul has changed camps.
over on the previous page my post 334 kinda cruels this one, I did previously subscribe to the rich and slow system as described by a certain brands instruction booklet but was told by a very knowledgable engine builder to replicate Dar's advice.
Why? In a nutshell you are suppossed to prepare the engine for its intended run conditions by replicating them as safely as possible and here over lubricating with a higher percentage of oil at run revs is the closest method possible, along with dropping the prop diameter to simulate the lack of load in the air.
To me running rich and slow does not prepare an engine for anything.
Thanks.
09-05-2011, 07:36 AM
#393
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RE: [Deleted]
Barry, you know how I break the Saito break in into 10 minute 1,000 rpm incriments, quite often during the 5,000 rpm 10 minute run the engine will slowly accelerate to 5,500 and then from 6,000 to about 6,200 during the 6,000 rpm 10 minute run. After that there is hardly any increase.
09-05-2011, 07:44 AM
#394
RE: Tapered-Bore Engine Break-in - Upgraded
Dar is right the fuel does a significant amount of cooling, more than the oil. But not all of the cooling is in the crankcase. Much of the fuel does not vaporise until it is in the cylinder. Also a rich mixture does not burn as hot as a lean one.
On the nitro funny cars and dragsters all of the cooling is from the fuel. They don't overheat unless they have a lean run. No oil involved in cooling other than by reducing friction.
On the nitro funny cars and dragsters all of the cooling is from the fuel. They don't overheat unless they have a lean run. No oil involved in cooling other than by reducing friction.
09-05-2011, 09:11 AM
#395
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RE: Tapered-Bore Engine Break-in - Upgraded
ORIGINAL: Recycled Flyer
Thats a strange thing to say since gasoline has no lubricating properties as such, its more that gas engines tend to be larger in size and so can physically support needle rollers on the big and small ends thereby eliminating the most critical oil dependant sliding part of the engine. And the finning on these engines seems to be proportionally much larger in area than its smaller glow cousins.
ORIGINAL: DarZeelon
Getting rid of the heat is apparently not the reason plane engines need more oil.
After all, gas guys easily get away with just 2-3%, or even less.
Getting rid of the heat is apparently not the reason plane engines need more oil.
After all, gas guys easily get away with just 2-3%, or even less.
Some small specialty engines had needle bearing con-rods too.
The one I know about is the discontinued MVVS #3070 GRRT/GRFT (differing in either front, or rear induction).
The methanol in the fuel cools through evaporation, mostly when it is in the combustion chamber.
In the crankcase it cools through sheer mass. Methanol is used at about 2.4 times the rate of gasoline/petrol.
This is one of the reasons our glow engines have (and need) smaller cooling fins.
Your info on the lapped engines makes sense.
