Kawasaki Concours Forum
The C10, aka Kawasaki Concours - The Original => The Bike - C10 => Topic started by: timsatx on September 27, 2013, 10:44:30 PM
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I finally found this series of articles. I found it once before forgot the link. I found it very interesting.
http://www.bobistheoilguy.com/motor-oil-101/ (http://www.bobistheoilguy.com/motor-oil-101/)
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A friend once told me that the most important thing about engine oil is to use some. ;D
Some oils can go longer between oil changes (Synth & semi-Synth), some have friction modifiers (not to be used with wet clutches) but otherwise use the correct viscosity and change at the recommended intervals.
Personally on my older bikes I change every 5k miles, mainly because it's easier to remember.
When the odometer goes past x5,000 or x0,000 it's oil change time.
I also use flushing oil when it's an x0,000 oil change.
So far 170k miles and still going.
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Flushing oil?
Please explain and pardon my ignorance.
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I think he's talking about flushing his engine.
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Interesting read. That guy must be a VERY successful surgeon and biochemist. Ferrari, Lamborghini, Maybach... Dr. Jay Leno.
My first car in 1974 was a 1966 Olds 442. Someone had done some work on it as the heads were not original. It never had good oil pressure. I took it to college in Tucson, AZ and in the heat oil pressure got worse. To get the oil pressure up I put thicker oil and sometimes STP. Eventually the engine seized. When I took the intake manifold off the cam was in 3 pieces. Now I know why. Would have been better with thinner oil and low oil pressure. Of course would have been better to figure out why the pressure was low and fix it but I was living on Raman at the time and had zero money.
Also now confirms what I always thought, Rotella 5-40 is not too thin for my 3 ATV's and 2 bikes.
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Right - I'm not familiar with flushing an engine. How does one do that?
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Right - I'm not familiar with flushing an engine. How does one do that?
Carefully... carefully... careful... l... y. 8)
http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=470189 (http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=470189)
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I sorta did it on my last oil change a couple of weeks ago. I added Seafoam to the oil and let it idle for about 20 minutes, then drained it. I might be more concerned about driving it but not just idling. In fact, I even put it into first and second gear to let it run for a minute and no problems.
http://seafoamsales.com/using-in-crankcase-oil/ (http://seafoamsales.com/using-in-crankcase-oil/)
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I have never gotten too excited about any of the amazing type oils. I guess they do not hurt anything. I just use regular motor oil, of the weight the manual says. I have never broken down when I had motor oil in the crankcase. Every engine I ever saw without motor oil was ruined. I have always gotten tired of motor vehicles before I wore them out. I don't care how good it is running, by 200,000 miles I want a different vehicle.
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I finally found this series of articles. I found it once before forgot the link. I found it very interesting.
http://www.bobistheoilguy.com/motor-oil-101/ (http://www.bobistheoilguy.com/motor-oil-101/)
A very interesting read that almost has me wanting to switch from dino Rotilla 15w40 to synth Rotilla 5w40. I use my bike for a lot of very short trips and the thinner oil during cold run may be an improvement.
One thing I am not so sure about in the article is the poo, pooing of the benefit of thicker oils clinging to parts better during overnight shutdown and providing protection on startup. While quick flow to bearing is very important there is a reason engine builders lube everything during assembly too. I guess the art is in knowing where to split the difference.
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I've had the same thoughts regarding cams and such retaining a better oil film if using a higher viscosity oil. I'm using the 5w40 and will continue unless someone come up with an answer.
I agree the 5w will be able to flow easier upon startup, and the parts would get 100% of oil quicker. How many engine revolutions does it take to start lubing at an acceptable level?
If you use a 20w, there is probably a thicker film of oil to begin with. How many engine revolutions does it take before lube starts flowing at an acceptable level and will the residual 20w film fall below what would have been left of 5w oil, and for how many revolutions?
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The misconception is that oils lube because they're "slippery".
Actually, they lube by hydraulically separating parts from each other.
To this end thinner oils will do this quicker and more easily
than thicker oils.
As far as thicker oils clinging to parts at rest, drop a camshaft
into a bucket of 50 weight oil and it will sink to the bottom,
in contact with the bucket. There is little to no protection at rest
other than from corrosion.
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The misconception is that oils lube because they're "slippery".
Actually, they lube by hydraulically separating parts from each other.
To this end thinner oils will do this quicker and more easily
than thicker oils.
As far as thicker oils clinging to parts at rest, drop a camshaft
into a bucket of 50 weight oil and it will sink to the bottom,
in contact with the bucket. There is little to no protection at rest
other than from corrosion.
While I do not totally disagree with you I also doubt anyone would want to crank up an engine that had zero lube on anything. ;) This is also the time an engine gets hammered with wear.
Oil does provide some very important lubrication on start up before proper flow (which I agree provides far more lubrication) is established.
The real question seems to be, what oil type/viscosity provides the best in both situations.
In a related story, A friend used to own "The Buggy Barn" and specialized in air cooled VW service and custom work.
He worked late into the night to build and install a custom 1776 cc engine using lots of a 50/50 mix of STP and Castrol 20w50 as assembly lube. He left the final plumbing and wiring for one of his employees to do in the morning.
The kids goes to work in the morning, gets everything all connected, fires it up and of course romps it out of the parking lot and down the street to "break it in."
Engine starts running like crap so he heads back and after about 8 miles it seizes up. He had not put ANY oil in the crankcase and of course it was trashed.
Without any thick oil film in that engine who thinks it would have driven anywhere near that far?
Built many VW motors and always used my friends homebrew assembly lube.
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Good information. Thanks for the link.
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Flushing oil? Please explain and pardon my ignorance.
Ignorance is FUTILE! ;D
Google is your friend.
(http://images.esellerpro.com/2697/I/139/76/WYN51265%20x4.jpg)
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The misconception is that oils lube because they're "slippery".
Actually, they lube by hydraulically separating parts from each other.
To this end thinner oils will do this quicker and more easily
than thicker oils.
As far as thicker oils clinging to parts at rest, drop a camshaft
into a bucket of 50 weight oil and it will sink to the bottom,
in contact with the bucket. There is little to no protection at rest
other than from corrosion.
This^
If any of you are familiar with Smokey Yunick, He did an experiment by building 2 identical smallblock chevy engines, except on had babbit shell bearings and the other had roller bearings. Of course there was alot of work to build the modular crank, etc, but he had high hopes that the roller motor would really produce great HP. When they dynoed the engines the produced the same HP. He scratched his head, then concluded that the regular bearings produced no excessive drag because the parts were being separated by the oil layer, and therefor there was no more friction than the roller motor had. He did conclude some power could be gained from lessening the oil pressure and the attending pumping losses, but didn't feel it offset the effort to build the roller crank assy. Steve
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I thought it was interesting, so I read his article until my eyes started to bleed.
Yes it is Interesting,,,,, but more than I really need to know to ride my Connie.
I run the Rotella T (15/40) Dino Oil and change it regularly. Works for me....
NOTE: Recently I tried the Rotella Synthetic.... It worked for me too.
I think it may have have shifted a bit better.
Cost MORE....
So, I went back to,,,, I run the Rotella T (15/40) Dino Oil and change it regularly.
Ride safe, Ted
PS: I live in Houston. Don't worry much about cold weather start ups...
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As far as thicker oils clinging to parts at rest, drop a camshaft
into a bucket of 50 weight oil and it will sink to the bottom,
in contact with the bucket. There is little to no protection at rest
other than from corrosion.
I don't know how this measures oils "clingability" which is the ability of oil not to drop off a part.
This method is the same technique used to measure viscosity.
Regards, Russell
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I don't know how this measures oils "clingability" which is the ability of oil not to drop off a part.
This method is the same technique used to measure viscosity.
Regards, Russell
Not sure dropping a cam in a bucket of oil proves that it only protects against corrosion.
Would you rather drop a nice cam in an empty bucket or one full of oil? ;)
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Not sure dropping a cam in a bucket of oil proves that it only protects against corrosion.
Would you rather drop a nice cam in an empty bucket or one full of oil? ;)
At rest there is metal-to-metal contact.
That contact continues until oil pressure can hydraulically
separate the components.
Hence the premise: "highest wear at start-up".
The thin film that "clings" is insufficient to protect
against this wear.
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Not saying that the film left on parts when the engine is not running prove much lube on start up but I am convinced it does provide some lube for critical moments.
Again, anyone ever assemble an engine dry?
If not, why not?
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I do not think that is quite right.
It is the spinning shaft that causes any hydrodynamic bearing to work, not oil pressure. In fact, oil pressure is not needed at all; a lot of machine tools use heavily loaded spindles that are lubricated simply by gravity feeding oil into the bearing. As long as the space between the shaft and the housing is full of oil, dynamic pressure takes care of the rest.
As to the part about parts actually touching when not moving, that can be correct. But modern oils have an extreme pressure package (additive) in them to prevent seizing even when parts actually touch each other. This also happens all the time between components such as gear teeth, even when the engine is actually running. Typical E.P. packages are ZDDP, molydisulfide and graphite although the last one is generally not used in internal combustion engines.
Brian
At rest there is metal-to-metal contact.
That contact continues until oil pressure can hydraulically
separate the components.
Hence the premise: "highest wear at start-up".
The thin film that "clings" is insufficient to protect
against this wear.
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BDF, you eloquently elaborated where my intention was omitted.
I meant to suggest contact would continue until the oil pump
could flow enough oil to provide lubrication.
Thanks for the clarification.
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I guess my question would be that if you do not think oil pressure is important then why not drain the oil from the engine and drive it?
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I guess my question would be that if you do not think oil pressure is important then why not drain the oil from the engine and drive it?
Because that is where the vast majority of lubrication comes from.
My only point is that I believe the oil film left on parts does also provide critical lubrication before oil pressure is established at start up. The art of all this is in finding an oil that allows rapid build up of pressure on start up AND provides an adequate film for lubrication for the brief moment before pressure is established.
Anyone ever know an engine builder who assembled engines bone dry?
Me either.
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Because that is where the vast majority of lubrication comes from.
My point exactly. The engine doesn't lay in oil, it requires oil pressure to lubricate it.
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Irrelevant and illogical question. Same as asking if you like salt? If you say yes, I ask why you do not eat five pounds per day?
Loaded questions are different and convey meaning in what appears to be a question but is really an accusation: "Have you stopped beating your wife yet?" would be such a question.
Now, want to talk about how oil works?
;)
I guess my question would be that if you do not think oil pressure is important then why not drain the oil from the engine and drive it?
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It does not, it only requires a film of oil to be present and that the rotating units in question do not overheat.
Lots of engines have hydro-dynamically lubricated bearings.... without a pressurized oiling system.
A pressurized oil system based engine requires pressurized only in that it has no alternative means to keep oil in the bearings. If such an engine were altered slightly, it would run perfectly well with nothing but slash lubrication and the occasional squirt (easy boys!) of oil where needed, such as at the bottom of the piston skirts and the bottom of the cylinder(s).
The key point here is that it is not the pressure provided by the oiling system that causes a hydro-dynamically lubricated bearing to work. Just do the pressure over area vs oil pressure and you will see that 40 PSI, 60 PSI is not sufficient to support either a main bearing or a rod journal bearing in any engine in any vehicle in any driveway. Speaking of mainstream America here- no telling what may be in the Australian outback for example :-)
Brian
My point exactly. The engine doesn't lay in oil, it requires oil pressure to lubricate it.
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It does not, it only requires a film of oil to be present and that the rotating units in question do not overheat.
Lots of engines have hydro-dynamically lubricated bearings.... without a pressurized oiling system.
A pressurized oil system based engine requires pressurized only in that it has no alternative means to keep oil in the bearings. If such an engine were altered slightly, it would run perfectly well with nothing but slash lubrication and the occasional squirt (easy boys!) of oil where needed, such as at the bottom of the piston skirts and the bottom of the cylinder(s).
The key point here is that it is not the pressure provided by the oiling system that causes a hydro-dynamically lubricated bearing to work. Just do the pressure over area vs oil pressure and you will see that 40 PSI, 60 PSI is not sufficient to support either a main bearing or a rod journal bearing in any engine in any vehicle in any driveway. Speaking of mainstream America here- no telling what may be in the Australian outback for example :-)
Brian
where do you get this stuff? It's not just the oil pressure supplied by the pump , but the clearance at the bearing which restricts the oils flow off the bearing and provides the film that separates the parts. This is why proper clearance is so critical. open up a clearance .002", pressure drops, oil film flows off and doesn't separate parts, parts soon go boom. If you've noticed, crank clearances have tightened up since the advent of low viscocity oils. Shell style bearing rely on zero parts contact, whereas roller bearings have constant contact. Shell bearings indeed do rely on oil pressure to separate the parts, case closed. Steve
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Okay then. Explain how 2 strokes work without oil pressure.
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:popcorn:
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Okay then. Explain how 2 strokes work without oil pressure.
Ummm....roller bearings.
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Steve, I have absolutely no idea what you are addressing here. I said that oil pressure is not necessary for a hydro- dynamic bearing. You respond with 'where do you get this stuff? It's not just the oil pressure supplied by the pump.... ' Right, I think I just said that.
Where do I get it? Oh, various places. Bernoulli's principle works modestly well here. Shear principles work fantastic. The shear gradient between the oil that <must> be stopped at the crankshaft bearing for example, will pick up speed in an exponential curve until it reaches the highest speed that it travels around the bearing, and then begin an exponential decline in speed until it reaches the bearing shell, where again the velocity is zero. It is these two velocity gradients that cause a pressure rise as the shaft is moved from the center of the bearing (away from the force applied to it). Got a lot of it in tribology courses.
Oil pumped under pressure is not needed to make a hydro dynamic bearing function. It is not needed to make it function any better either.
Take the pressure of the oil, multiplied by the area of 1/2 of the bearing journal and multiply them. Then tell me how 40 PSI of oil pressure across a couple of square inches of area, yielding 80 pounds of force is resisting four tons (8,000 lbs. ) of downward pressure in a conventional 350 cubic inch V-8 engine.....
Just curious, but what do you think allows small engine bearings to work without oil pumps? Briggs and Stratton, along with many, many other manufacturers have been making them and we have been using them for decades. ??
Opps, I didn't see where you had closed the case, sorry. ;D
Brian
where do you get this stuff? It's not just the oil pressure supplied by the pump , but the clearance at the bearing which restricts the oils flow off the bearing and provides the film that separates the parts. This is why proper clearance is so critical. open up a clearance .002", pressure drops, oil film flows off and doesn't separate parts, parts soon go boom. If you've noticed, crank clearances have tightened up since the advent of low viscocity oils. Shell style bearing rely on zero parts contact, whereas roller bearings have constant contact. Shell bearings indeed do rely on oil pressure to separate the parts, case closed. Steve
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Not to anyone in particular but you know, science really does explain quite well how all of this works. Really easy to find this information printed in texts all over the place. There is really no need to reinvent the wheel or tribology all over again. I would suggest we make use of what resources are available before venturing out on our own to 'explain' how things work.
"A little learning is a dangerous thing;
drink deep, or taste not the Pierian spring:
there shallow draughts intoxicate the brain,
and drinking largely sobers us again."
-Alexander Pope
Brian
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Okay then. Explain how 2 strokes work without oil pressure.
Roller Bearings support the crankshaft in small 2-Smokes and the oil in the gas lubes the piston walls; there is more than enough oil splashing around in the crankcase to keep the roller bearings supplied with the small amount of oil that they need...
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BDF, I dunno, maybe you're an engineer and I'm a lowly engine builder, but I get the feeling that you're trying to "baffle by bullsh*t"
Here's some info on how oil separates parts on what I'm calling "shell bearings" http://en.wikipedia.org/wiki/Fluid_bearing (http://en.wikipedia.org/wiki/Fluid_bearing)
If your theories are sound and correct, all modern engine automotive designs are incorrectly designed with shell bearings, because according to you, oil pressure is apparently not needed to separate the parts, but merely provide lubrication. If you are correct, then why are modern engines designed with pressure pumps at all? It's well known that there are power losses due to pumping loss, and any effort to achieve best efficiency would want to rid pumping loss all together. Yet we still have presurized oil systems and shell bearings as the common method of design. what are all these engine designers missing? Steve
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First off Steve, these are not 'my' theories, anymore than gravity or relativity is 'my' theory. That said, I do subscribe to them and try my best to follow along.
I have no idea how engine building would school one in the ways of fluid dynamics anymore than carrying rocks for a living would give one a solid understanding of physics. But in any event, you are the one who brought up what each of us may do or may be; I am happy to leave that alone and talk about the subject at hand. Frankly, I do not care what you do or have done unless it has some bearing (moderate pun intended) on the operation of.... well, bearings. And I do not mean you have tightened the main bearing caps of a gazillion engines down correctly; looking at a battery, even for a very long time or perhaps many, many batteries, will not help one understand how or why they produce electricity.
I can understand your comment about the bafflement. Complex things often seem as if they could be simplified; sometimes that is true, sometimes not. In this particular case, you seem to want the oil pump to be providing the mechanism by which plain bearings work; that would surely be the simple answer but unfortunately it is not correct. Rotational speed of the shaft, shear forces and the velocity gradient w/in the oil layer are the sources of the mechanism by which plain journal bearings work.
That is a fine link you provided and I am in agreement that it well illustrates how fluid dynamics work within a plain journal bearing. From that page, in addition to the key references to the Reynolds number, these bullet points alone describe, as simply as I believe can be done, how a fluid filled bearing works to resist the forces trying to force the shaft sideways w/in the bearing housing:
Begin sited page quote:
Hydrodynamic condition – Load:
Increase in load decreases minimum film thickness
Also increases pressure within the film mass to provide a counteracting force
Pressure acts in all directions, hence it tends to squeeze the oil out of the ends of the bearing
Increase in pressure increases fluid viscosity
End sited page quote:
Now notice that an increase in load increases pressure withing the film mass to provide a counteracting force, as well as the sentence 'increase pressure increases fluid viscosity'. That is the entire key is to why plain journal wet bearings work. Notice the lack of reference to any externally applied pressure; it simply does not apply to the mechanics at work here.
Brian
BDF, I dunno, maybe you're an engineer and I'm a lowly engine builder, but I get the feeling that you're trying to "baffle by bullsh*t"
Here's some info on how oil separates parts on what I'm calling "shell bearings" http://en.wikipedia.org/wiki/Fluid_bearing (http://en.wikipedia.org/wiki/Fluid_bearing)
If your theories are sound and correct, all modern engine automotive designs are incorrectly designed with shell bearings, because according to you, oil pressure is apparently not needed to separate the parts, but merely provide lubrication. If you are correct, then why are modern engines designed with pressure pumps at all? It's well known that there are power losses due to pumping loss, and any effort to achieve best efficiency would want to rid pumping loss all together. Yet we still have presurized oil systems and shell bearings as the common method of design. what are all these engine designers missing? Steve
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Problem here is that everyone is correct.
Properly designed crank bearings lubricated by oil under pressure are far superior and will last much longer than similar ones that are submerged in oil or splash lubed. That said, I do have a heck of a lot of hours on my Briggs powered push mower.
Steve is spot on that high revving engines such as those we ride really call for oil pressure in the bearings. Because these motors have zero oil pressure on cranking and start up, I also bet he lubes the crap out of them when he assembles engines because that provides some lubrication at a critical moment too. ;)
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I feel like this is another conversation with a politician. Why do I bother?
So for a clarification to the onlookers, let me respond in this manner.
Your original contention (or at least how I understood your point) was that forced (pumped) oil pressure was unnecessary for separating the rotating parts of an engine. My point is that forced oil is necessary in this instance, if using shell style (not ball or needle) style bearings.
I also pointed out the necessity for controlling clearances, oil film flow speed, etc.
The elements of how the film creates a wedge are all part and parcel of the function of the rotation of the parts. How much oil reaches the bearing is set by viscosity, oil system design, clearances in other parts of the engine, etc. What happens on one single shell style bearing - lets say a rod bearing - is going to be a function of the oil pressure, viscosity, clearance, rotational speed, width of bearing, side clearances, etc.
To think that this bearing system doesn't rely on forced oil as the first part of the design would be ludicrous. Without forced oil, this system could not function, well, not long enough to provide any service.
Let's also look at heat build-up on the bearing and shaft. Forced oil, flowing off the side clearances, carries away the heat. This is again another place where viscosity plays a key role. If the film is to thin, it flows off the bearing sufficiently, but the wedge thickness can be crushed by the forces applied at a given point in the rotation - think "power stroke" and you'll see what I mean. If the oil is to thick, it provided better protection in terms of separating the parts, but the slow flow off the surface results in excessive heat build up in the parts.
Crankshafts are drilled so that the bearing gets a fresh shot of oil from the system just as the highest loads are being applied through the rod. If pumped oil was really unnecessary, then why insure the highest amount of fresh, cool (relative to the parts being oiled) , pressurized oil is applied as the power stroke occurs, and that the top shell of a rod gets this oil during said power stroke?
One of the failures that can occur to engine rod bearings occurs when pre ignition takes place. Basically the piston / rod is slammed down onto the crank while the crank is still reaching or at TDC. The result isn't to rotate the crank, but hammer the rod bearing top shell into the crank. This is one place where the hydrostatic fluid wedge often gets overwhelmed and is pushed out. Bearing hits crank, and permanent damage is the result. Not just from heat but from deformation. Have you ever seen a shell bearing lose it's crush?
This happens because of the bearing being hammered into the crank, from oil film loss, not heat.
Of course, all my ramblings are moot if you take the politician's approach, and try to fall back on "the oil film strength is provided by rotational force, viscosity, etc" sure, true, to an extent - but the big problem with that theory is that if forced oil had not been introduced to the journal / bearing to start the process then the film strength from rotation, etc could never develop regardless, and therefore engines with shell style bearings rely on forced oil, period. Steve
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BDF, I have an idea- rather than operate in acedemia, let's work in the real world.
I'll use my engine in my c-10, you use yours in your c-14.
I'll use my understanding of oiling, and leave my engine as I built it. Seems good, it's lasted about 40k of beatings so far.
Now for your c-14, let's see if forced oil is unnecessary. It will be simple to do. simply connect a hose from a tap into the oil system, and route said hose back into the oil pan. perhaps include a valve, so we can set the oil pressure in the engine to 1# pressure, which will insure lubrication to all parts. Now go for a ride.
Since we'll probably both be at the National this year, I suggest we do this experiment there. Heck we'll go ride together. Me, with 40# oil pressure, you, with 1#. Let the real world results prove who's correct. I'm looking forward to it.
Oh, before I forget... bring a trailer so you can get your bike home. :yikes: Steve
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Ego and testostorone I assume is why you bother. I mean we are barely 400, 500 generations away from caveman status, and only maybe 1,400 generations since our final species development (see sig. line for help here) and while we have evolved, that evolution has certainly not kept up with our knowledge growth. So it is pretty natural to want to beat your chest and be right rather than being correct. I feel the same urge, I just fight it with reason and logic.
I think the on- lookers have more then enough information here to form their own conclusions. ;)
I bid you good day. :-)
Brian
I feel like this is another conversation with a politician. Why do I bother?
So for a clarification to the onlookers, let me respond in this manner.
<snip>
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Where? Acedemia? Is that a school for learning card tricks? A skin disease that looks like a sports wrap on the face?
See, there is that testosterone and ego.... :rotflmao:
Lighten up Steve, it is just oil and I don't think either one of us sells the stuff, right?
Brian (reason says leave it alone, ego says 'go get 'im!'.... still hoping for reason to win)
BDF, I have an idea- rather than operate in acedemia, let's work in the real world.
<snip>
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Take the pressure of the oil, multiplied by the area of 1/2 of the bearing journal and multiply them. Then tell me how 40 PSI of oil pressure across a couple of square inches of area, yielding 80 pounds of force is resisting four tons (8,000 lbs. ) of downward pressure in a conventional 350 cubic inch V-8 engine.....
Using the same logic that pressure from the oil pump cannot overcome the downward pressure makes me wonder how oil would get in there by its own means without pressure.
Regards, Russell
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Excellent- I always wanted to be correct but remember, now I'm going to quote you on that being correct part :-)
I cannot even remember why I am over here on the C-10 side....? I don't normally read this part of the forum. Never had a C-10 and never formed an opinion about the oil used in them either. ??
Youse guys should come over to the C-14 side and we'll chat about KiPass- it is great fun, never ends and beats the tar out of an oil thread every single time. ;D
Brian
Problem here is that everyone is correct.
Properly designed crank bearings lubricated by oil under pressure are far superior and will last much longer than similar ones that are submerged in oil or splash lubed. That said, I do have a heck of a lot of hours on my Briggs powered push mower.
Steve is spot on that high revving engines such as those we ride really call for oil pressure in the bearings. Because these motors have zero oil pressure on cranking and start up, I also bet he lubes the crap out of them when he assembles engines because that provides some lubrication at a critical moment too. ;)
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I feel a disturbance in the force.... Note the time of this post.
:rotflmao: :rotflmao:
Brian
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Using the same logic that pressure from the oil pump cannot overcome the downward pressure makes me wonder how oil would get in there by its own means without pressure.
Regards, Russell
When you consider centrifical force constantly trying to throw the oil away from the crank, it's obvious that the faster the crank rotates, the less splash oiling works, and pressurized oiling is the only way to overcome the mechanical forces.
Brian, none of this was chest beating or ego. We have different opinions. You are obviously an educated guy. I'm not. In fact, usually I'm to dumb to realize I can't do something when an educated person tells me "you can't do that, it doesn't work", so I just do it anyway. Steve
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Nah, my mistake. Not even a minor disturbance.
;)
Brian
I feel a disturbance in the force.... Note the time of this post.
:rotflmao: :rotflmao:
Brian
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http://www.valorebooks.com/textbooks/fundof-fluid-film-lubrication/9780070259560 (http://www.valorebooks.com/textbooks/fundof-fluid-film-lubrication/9780070259560) $35 including shipping. Education is easy, it is tenacity that is harder to find.
I don't really think this is a matter of opinion.... of course, that is just my opinion about your opinion of what you claim is an opinion in the first place. :o ;D
If you are really interested, this is a machine that has five (5) spindles, uses hydrodynamic bearings to support them, and does not have a pressurized lube system. The oil is fed from above and distributed to each spindle as the spindle group rotates; each spindle only gets lubed when it is at the top of the spindle housing. The original Davenport design is over 100 years old and has been in continuous use for all that time. Odds are, you have many things right around you that fell out of one of those machines..... maybe like the pins on the ends of a nearby fluorescent lamp tube? http://www.davenportmachine.com/about.asp (http://www.davenportmachine.com/about.asp) I have seen those machines so heavily loaded that the spindles themselves are visibly deflected yet spindle seizures are virtually unheard of. Top spindle speed is ordinarily 3,883 RPM and once running they typically run for days or weeks without being stopped other than to reload stock.
Brian
<snip>
Brian, none of this was chest beating or ego. We have different opinions. You are obviously an educated guy. I'm not. In fact, usually I'm to dumb to realize I can't do something when an educated person tells me "you can't do that, it doesn't work", so I just do it anyway. Steve
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When you consider centrifical force constantly trying to throw the oil away from the crank, it's obvious that the faster the crank rotates, the less splash oiling works, and pressurized oiling is the only way to overcome the mechanical forces.
Yes that's what I was getting at. Brian is correct about how a hydrodynamic bearing and its lubrication works but the problem is getting the oil between the surfaces and keeping it there. In relation to its practicality for automotive use the Wikipedia article points out the following:
"Hydrodynamic bearings rely on bearing motion to suck fluid into the bearing, and may have high friction and short life at speeds lower than design, or during starts and stops. An external pump or secondary bearing may be used for startup and shutdown to prevent damage to the hydrodynamic bearing"
Another problem is expansion/contraction of surfaces due to heat.
Regards, Russell
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In the Davenport machine website a rebuild includes "Lubrication system with motorized pump".
The tech specs for the Davenport HP shows:
"[Constant Low Pressure Lubricator #SB-2446-1
(Ways and Servo Motors)
Required Lubricant
Mobil Vactra (Heavy)
Reservoir Capacity
8 Liters
Lube Pump Output
100 cc/min.
Pressure Setting
25-30 psi
System Voltage
480 V, 50/60Hz 3 Phase, 50 Amp"
Regards, Russell
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Wrong machine. Anything with servos is not 100 years old.
You want the Model B. All mechanical. Besides all that, the spindle is lubed through a port to the outside of the spindle housing that rotates and is only lined up with the feed line in one position of the five index positions (it is a five spindle machine). Don't make me get Kirby to take a photo with a Davenport spindle bearing....
Seriously, trust me on this one- I have stood next to them and all their splendid 103 decibel glory (make the bones of your head conduct sufficient vibration that ear plugs don't work). I would lie to you guys but not about this- I would save it up for something more important.... Really.
Hydrodynamic bearings do not work on nor do they need, a pressurized feed. At least beyond the pressure needed to move the fluid into the bearing itself (rule #994: fluids move ONLY because of a pressure differential); gravity feed is fine and dandy. Again, think about it: the pressure supplied to the oil galleys in an engine is never 100 PSI, always less. To push a hydraulic cylinder piston forward within the cylinder, what is required is enough pressure and enough piston area to generate sufficient force to move whatever is resisting it.
Hey, just thought of an excellent example: the wrist pin inside of any engine.... no pressurized lube there but it bears the same pressure as the con rod and main bearings. There ya' go, if pressure was necessary to make a con rod bearing work, how could the wrist pin survive the same amount of force without any pressure? The reason is because of the pressure gradient w/in the oil film.
Brian
In the Davenport machine website a rebuild includes "Lubrication system with motorized pump".
The tech specs for the Davenport HP shows:
"[Constant Low Pressure Lubricator #SB-2446-1
(Ways and Servo Motors)
Required Lubricant
Mobil Vactra (Heavy)
Reservoir Capacity
8 Liters
Lube Pump Output
100 cc/min.
Pressure Setting
25-30 psi
System Voltage
480 V, 50/60Hz 3 Phase, 50 Amp"
Regards, Russell
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I have done some light reading, and understand the difference between what BDF and I are saying.
BDF is speaking about "hydrodynamic bearings" and he is correct, in that the rotational speed of the shaft alone builds the bearing wedge from the bearing fluid. This type of bearing is only applicable over a set rpm range.
I'm speaking about "hydrostatic bearings" which need an external pump to provide the bearing fluid. This bearing is applicable regardless of speed, because it doesn't rely on speed of the parts to develop the bearing wedge.
Problem is, we're talking about motorcycle engines, so any discussion of hydrodynamic bearings is rendered useless by the functional nature of the application. Hydrodynamic bearings would be a gross misapplication in this case, so I don't understand why that was interjected into this conversation from the get-go. HTH, Steve
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You guys are entertaining.
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OK but who is more entertaining? Me or him? Who is it? C'mon, you have to pick.
;D
Brian
You guys are entertaining.
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There ya' go Steve, fixed it up for ya.
Do some heavier reading and see the range that hydrostatic bearings work within. Not heavy reading but less light that what you've done so far.
You are right Gary, this is entertaining! And I have been wasting my time on this forum for year on KiPass.... :rotflmao:
Now you guys do know we passed the line of good sense some time back, around the time Steve said something like 'I don't know why I bother....'. At this point the only thing left is the humor.
So Steve, if we do meet at the national, I'll buy you a drink (of your choice) and you can give me your theories on gravity while you pour it up your gullet. No, wait, I mean down your gullet. [duckin', grinnin' and runnin']
Brian
I have done some light reading and I am going to try and be right from a different angle. If that doesn't work, I will do some light drinking and come up with another story.
<snip>
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wow Brian, you sure know how to handle an olive branch ::)
Here. I'll give you a chance to get the last word, not that you needed any coaxing...
I'd like to know why you interjected your knowledge on hydrodynamic bearings when the subject is motorcycle engines and hydrodynamic bearings aren't germaine to the application? And why bother to take me to task, when virtually everything I posted about the functionality of the bearings used in our engines was correct? Steve
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wow Brian, you sure know how to handle an olive branch ::)
Here. I'll give you a chance to get the last word, not that you needed any coaxing...
I'd like to know why you interjected your knowledge on hydrodynamic bearings when the subject is motorcycle engines and hydrodynamic bearings aren't germaine to the application? And why bother to take me to task, when virtually everything I posted about the functionality of the bearings used in our engines was correct? Steve
Seems to me that this thread has more than run it's course; thus I'll have the last word...
And the word is CLOSED ...