Vech states in his article "When the deposit gets deep enough, the sludge will then migrate down the rod pin, and plug the two small oil holes, cutting off the flow of oil." That causes the bearing failure.
Kurt in S.A.
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Proposal for Self Cleaning Slinger Rings
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schrader7032
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Proposal for Self Cleaning Slinger Rings
Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2
Fast. Neat. Average. Friendly. Good. Good.
'78 R100/7 '69 R69S '52 R25/2
Fast. Neat. Average. Friendly. Good. Good.
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Allan.Atherton
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Proposal for Self Cleaning Slinger Rings
... The photo showing the particles being magnetic, did it come out of an engine equipped with magnets? Would it be magnetic had magnets been used?...
That engine did not have pan magnets. Pan magnets remove all ferrous material from the oil quickly, leaving the pan and even the drain plug magnet clean:
http://www.flickr.com/photos/roundel/sets/58280/
... I also noticed the overflow of particles in the rod journals and the other photo illustrating a failed rod bearing. The bearing looked to be completely impacted with particles, but I could not be sure....
You refer to this photo:
http://www.flickr.com/photos/roundel/98357351/
The bearing may contain particles that flowed over in the oil from the full slinger, but most of the material you see is debris from the last stage of failure where the rollers became square tubes, stopped rolling and chewed up the cage.
... What caused the bearing failure? Are the passages clogging first or second? I am wondering if the bearing cages first fill with particles that cannot escape then become impacted causing the oil passages to back up and clog second. Can you clarify this? What actually cuts off the oil flow?
The flow is gradually restricted by particles that overflow from the full slinger into the little hole into the hollow crank pin. The sludge obstructs this hole and the two holes in the side of the pin that feed the rod bearing.
http://www.flickr.com/photos/roundel/98357357/
http://www.flickr.com/photos/roundel/98357355/
The oil flow through the crank pin is reduced gradually and wear accelerates due both to dirty oil and less oil. This wear can continue for over ten thousand miles, with gradually increasing rod knock. At some point the holes become so plugged that the bearing is starved, actual damage begins to occur, and ends with the destruction of the bearing.
I doubt that sludge particles fill and become packed in the bearing. The holes into and out of the crank pin are the restriction. Following your line of thinking, I wonder if the effect of full slingers would be greatly delayed if the crank pin holes were made larger so they did not plug up. Then there would be wear from dirty oil, but no starvation.
That engine did not have pan magnets. Pan magnets remove all ferrous material from the oil quickly, leaving the pan and even the drain plug magnet clean:
http://www.flickr.com/photos/roundel/sets/58280/
... I also noticed the overflow of particles in the rod journals and the other photo illustrating a failed rod bearing. The bearing looked to be completely impacted with particles, but I could not be sure....
You refer to this photo:
http://www.flickr.com/photos/roundel/98357351/
The bearing may contain particles that flowed over in the oil from the full slinger, but most of the material you see is debris from the last stage of failure where the rollers became square tubes, stopped rolling and chewed up the cage.
... What caused the bearing failure? Are the passages clogging first or second? I am wondering if the bearing cages first fill with particles that cannot escape then become impacted causing the oil passages to back up and clog second. Can you clarify this? What actually cuts off the oil flow?
The flow is gradually restricted by particles that overflow from the full slinger into the little hole into the hollow crank pin. The sludge obstructs this hole and the two holes in the side of the pin that feed the rod bearing.
http://www.flickr.com/photos/roundel/98357357/
http://www.flickr.com/photos/roundel/98357355/
The oil flow through the crank pin is reduced gradually and wear accelerates due both to dirty oil and less oil. This wear can continue for over ten thousand miles, with gradually increasing rod knock. At some point the holes become so plugged that the bearing is starved, actual damage begins to occur, and ends with the destruction of the bearing.
I doubt that sludge particles fill and become packed in the bearing. The holes into and out of the crank pin are the restriction. Following your line of thinking, I wonder if the effect of full slingers would be greatly delayed if the crank pin holes were made larger so they did not plug up. Then there would be wear from dirty oil, but no starvation.
Proposal for Self Cleaning Slinger Rings
I am sorry, I did not see your last post before posting this.
I did read Vech’s article and believe it to be right on. I am still having a hard time understanding why the particles start clogging in the first place rather than flow on through to the oil pan. I am starting to think it is the rod bearing design that is at fault. From the few photos I am able to view and my own engine when overhauled, it looks like it is actually the bearing cages that are the real traps and the slinger buys time trapping some of the particles. So here is a question, what clogs first, the bearing cage then the oil passages clogs from backup? Or do the oil passages clog shortly after the slinger fills and there is still room in the cages? From the picture of the failed rod bearing, it looks like the bearing fills with particles causing oil starvation. Before it totally starves the oil flow is severely reduced, thus reducing oil cooling. So while the rod bearing is running hot, it bakes the little bit of oil there causing oil break down, varnish, sticky stuff, etc. In the end this just accelerates the problem.
To me there is a progression of how the particles accumulate. Let’s say the first few times particles enter the cup they stay loose for awhile. When the engine stops, all the loose particles and oil flows to the bottom of the cup. A small pile of particles probably forms at the bottom of the slinger cup. Much of the oil then spills over the lip of the cup and carries some of the particles away. I would imagine this is a form of self cleaning to some degree. The next startup, the cups must be primed to full again with oil. The small pile of particles must level out. The top of the pile may get picked up in the first wave of oil and be swept into the oil holes and rod bearings in small doses. This initial dump of particles into the bearing now has dirtied the oil in the cage. If these particles are indeed trapped in the bearing cage, then they are re-circulated over and over into smaller particles until small enough to flow out. Many of the small crushed particles are squeezed into a past. The past eventfully impacts into all the open spaces and the bearing cage fills up killing oil circulation. Oil starvation and overheating is inevitable. Since the oil pressure and volume is so low, next to nothing is pushed out. Rather than this bearing running in clean semi filtered oil, it is really running in dirty oil constantly more than we believe.
My point is the bearing cage is a trap, the oil there is really dirty oil all the time. Eventually it fills with sticky paste and particles; and then oil starvation and overheating destroys the bearing.
Adding a pleated oil filter may not really help very much as the real problem is the bearing design. It does not allow adequate circulation or self cleaning.
Are the rod bearings cleaned when the oil slingers are cleaned or changed? If not they probably should be.
I am sure people smarter than me have gone over this subject plenty. BMW engineers gave up on it and only offered a cleaning schedule. We hail the innovative design for the times, but what an embarrassing design flaw -- total dis-assembly for routine cleaning. It really just makes me wonder if there still may not be something that can be done to move these particles along.
What do you all think?
I did read Vech’s article and believe it to be right on. I am still having a hard time understanding why the particles start clogging in the first place rather than flow on through to the oil pan. I am starting to think it is the rod bearing design that is at fault. From the few photos I am able to view and my own engine when overhauled, it looks like it is actually the bearing cages that are the real traps and the slinger buys time trapping some of the particles. So here is a question, what clogs first, the bearing cage then the oil passages clogs from backup? Or do the oil passages clog shortly after the slinger fills and there is still room in the cages? From the picture of the failed rod bearing, it looks like the bearing fills with particles causing oil starvation. Before it totally starves the oil flow is severely reduced, thus reducing oil cooling. So while the rod bearing is running hot, it bakes the little bit of oil there causing oil break down, varnish, sticky stuff, etc. In the end this just accelerates the problem.
To me there is a progression of how the particles accumulate. Let’s say the first few times particles enter the cup they stay loose for awhile. When the engine stops, all the loose particles and oil flows to the bottom of the cup. A small pile of particles probably forms at the bottom of the slinger cup. Much of the oil then spills over the lip of the cup and carries some of the particles away. I would imagine this is a form of self cleaning to some degree. The next startup, the cups must be primed to full again with oil. The small pile of particles must level out. The top of the pile may get picked up in the first wave of oil and be swept into the oil holes and rod bearings in small doses. This initial dump of particles into the bearing now has dirtied the oil in the cage. If these particles are indeed trapped in the bearing cage, then they are re-circulated over and over into smaller particles until small enough to flow out. Many of the small crushed particles are squeezed into a past. The past eventfully impacts into all the open spaces and the bearing cage fills up killing oil circulation. Oil starvation and overheating is inevitable. Since the oil pressure and volume is so low, next to nothing is pushed out. Rather than this bearing running in clean semi filtered oil, it is really running in dirty oil constantly more than we believe.
My point is the bearing cage is a trap, the oil there is really dirty oil all the time. Eventually it fills with sticky paste and particles; and then oil starvation and overheating destroys the bearing.
Adding a pleated oil filter may not really help very much as the real problem is the bearing design. It does not allow adequate circulation or self cleaning.
Are the rod bearings cleaned when the oil slingers are cleaned or changed? If not they probably should be.
I am sure people smarter than me have gone over this subject plenty. BMW engineers gave up on it and only offered a cleaning schedule. We hail the innovative design for the times, but what an embarrassing design flaw -- total dis-assembly for routine cleaning. It really just makes me wonder if there still may not be something that can be done to move these particles along.
What do you all think?
Ole Guy
1954 R51/3
1954 R51/3
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Allan.Atherton
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Proposal for Self Cleaning Slinger Rings
... it looks like it is actually the bearing cages that are the real trap... what clogs first, the bearing cage then the oil passages clogs from backup? Or do the oil passages clog shortly after the slinger fills and there is still room in the cages? From the picture of the failed rod bearing, it looks like the bearing fills with particles causing oil starvation.... the bearing cage is a trap... Eventually it fills with sticky paste and particles; and then oil starvation and overheating destroys the bearing....
The hard caked sludge requires the centrifuge of the slinger to form. The little holes in the crank pin are the choke points. The con rod bearings are not a trap and continue to flow whatever oil they receive, until they wear to pieces.
... Are the rod bearings cleaned when the oil slingers are cleaned or changed?...
The con rod bearings are rinsed when the slingers are cleaned; this is not to clean them, but to free them of the oil film. They are rinsed in gas and dried so that any free play from wear can be heard as a clicking and also measured. When the con rod bearings are rinsed, there is no sticky or hard sludge in them. The click test: hold a con rod in one fist with the rest of the crank dangling, and hit the top of that fist with the other.
... what an embarrassing design flaw -- total dis-assembly for routine cleaning...
It is true that the slingers were given routine cleaning. This would occur when the engine was disassembled for complete overhaul on the occasion of the piston to cylinder clearance reaching the allowable tolerance of .012 mm over assembly clearance. This typically happened every 75,000 miles, at which time the main bearings were also replaced.
The oil slingers were a solution to both oil distribution and oil cleaning, in the era before filtering, and the service interval of 75,000 miles or more was not an inconvenience. The other motorcycles of the same era had a much shorter time between failure or overhaul, sometimes as little as 10,000 miles. BMW had nothing to be embarrassed about.
I bought my first slinger-ed bike new in 1966, and got used ones in 1973 and 1985. I never heard slingers mentioned until the late 80s when so many bikes with high-miles or poor histories were being found and restored. At that time, and ever since, the issue of slingers has been important. You must know your slinger history, lest you be riding with full ones.
The hard caked sludge requires the centrifuge of the slinger to form. The little holes in the crank pin are the choke points. The con rod bearings are not a trap and continue to flow whatever oil they receive, until they wear to pieces.
... Are the rod bearings cleaned when the oil slingers are cleaned or changed?...
The con rod bearings are rinsed when the slingers are cleaned; this is not to clean them, but to free them of the oil film. They are rinsed in gas and dried so that any free play from wear can be heard as a clicking and also measured. When the con rod bearings are rinsed, there is no sticky or hard sludge in them. The click test: hold a con rod in one fist with the rest of the crank dangling, and hit the top of that fist with the other.
... what an embarrassing design flaw -- total dis-assembly for routine cleaning...
It is true that the slingers were given routine cleaning. This would occur when the engine was disassembled for complete overhaul on the occasion of the piston to cylinder clearance reaching the allowable tolerance of .012 mm over assembly clearance. This typically happened every 75,000 miles, at which time the main bearings were also replaced.
The oil slingers were a solution to both oil distribution and oil cleaning, in the era before filtering, and the service interval of 75,000 miles or more was not an inconvenience. The other motorcycles of the same era had a much shorter time between failure or overhaul, sometimes as little as 10,000 miles. BMW had nothing to be embarrassed about.
I bought my first slinger-ed bike new in 1966, and got used ones in 1973 and 1985. I never heard slingers mentioned until the late 80s when so many bikes with high-miles or poor histories were being found and restored. At that time, and ever since, the issue of slingers has been important. You must know your slinger history, lest you be riding with full ones.
Proposal for Self Cleaning Slinger Rings
Allan,
Thank you for clearing up my questions. It is good to know the rod bearings do not retain buildup and it is confined to the slingers.
I have a few more questions about the slingers. I am still wondering if the original intent was to retain particles or just to feed oil to the bearings. Maybe the buildup of particles was an unintended consequence.
After examining the slinger I am curious about the height of the outer lip in relation to the oil exit hole. Was there to be more oil flowing into the slingers so some would over flow the lips? The devise is called a slinger. It makes me wonder if the intent was to over fill it so oil would then be slung off to lubricate the cam, lifters, etc. What flies away from the rod bearings may just be supplementing the slingers. Has anyone ever examined the path or aim of splatter? Would this matter? The reason I ask this is because I noticed the lip is not that much higher than the oil passage to the connecting rod. If all the oil was to exit the connecting rod, the lips might have been made higher to ensure this was so. If the lip was too high then too much may have fed to the bearings. As it looks to me, maybe some was intended to over flow for slinging.
Here is what I am trying to figure out: Was filtering planned and is it necessary? If it was not necessary, then trying to figure out a way to prevent particle build up might still be feasible. Much of what is collected in the slingers would have been drained out each oil change if it made it back to the pan.
To me the volume of particles captured are not really that much. Does it really matter to trap them? Trapping that little, does it really add to the longevity of the bearings and crank?
If the particles are agitated and prevented from settling in the slingers, these small amounts for each oil change may not make any difference at all. Thus the engine service life may actually be extended until it really needs to be opened.
I am still in favor of at least trying to determine if this self cleaning slinger idea is still feasible. As of now I think it is worth a try. The worst that can happen is the volume of particles trapped in 50,000 to say 150,000 miles will be allowed to circulate between oil changes. If this makes no difference, then the next biggest detriment would be the oil passages clog prematurely as they do now. To me that should be the reason this does not work if engine wear is not a factor. Maybe some sort of mock up to test the theory might help? Or just try the idea on the front slinger so it can be examined periodically.
I still feel optimistic. There are other devise besides ball bearing to do the job of agitation, such a star type scrappers.
What do you think?
Thank you for clearing up my questions. It is good to know the rod bearings do not retain buildup and it is confined to the slingers.
I have a few more questions about the slingers. I am still wondering if the original intent was to retain particles or just to feed oil to the bearings. Maybe the buildup of particles was an unintended consequence.
After examining the slinger I am curious about the height of the outer lip in relation to the oil exit hole. Was there to be more oil flowing into the slingers so some would over flow the lips? The devise is called a slinger. It makes me wonder if the intent was to over fill it so oil would then be slung off to lubricate the cam, lifters, etc. What flies away from the rod bearings may just be supplementing the slingers. Has anyone ever examined the path or aim of splatter? Would this matter? The reason I ask this is because I noticed the lip is not that much higher than the oil passage to the connecting rod. If all the oil was to exit the connecting rod, the lips might have been made higher to ensure this was so. If the lip was too high then too much may have fed to the bearings. As it looks to me, maybe some was intended to over flow for slinging.
Here is what I am trying to figure out: Was filtering planned and is it necessary? If it was not necessary, then trying to figure out a way to prevent particle build up might still be feasible. Much of what is collected in the slingers would have been drained out each oil change if it made it back to the pan.
To me the volume of particles captured are not really that much. Does it really matter to trap them? Trapping that little, does it really add to the longevity of the bearings and crank?
If the particles are agitated and prevented from settling in the slingers, these small amounts for each oil change may not make any difference at all. Thus the engine service life may actually be extended until it really needs to be opened.
I am still in favor of at least trying to determine if this self cleaning slinger idea is still feasible. As of now I think it is worth a try. The worst that can happen is the volume of particles trapped in 50,000 to say 150,000 miles will be allowed to circulate between oil changes. If this makes no difference, then the next biggest detriment would be the oil passages clog prematurely as they do now. To me that should be the reason this does not work if engine wear is not a factor. Maybe some sort of mock up to test the theory might help? Or just try the idea on the front slinger so it can be examined periodically.
I still feel optimistic. There are other devise besides ball bearing to do the job of agitation, such a star type scrappers.
What do you think?
Ole Guy
1954 R51/3
1954 R51/3
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Allan.Atherton
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Proposal for Self Cleaning Slinger Rings
... I am still wondering if the original intent was to retain particles or just to feed oil to the bearings. Maybe the buildup of particles was an unintended consequence... ... Was filtering planned and is it necessary? If it was not necessary, then trying to figure out a way to prevent particle build up might still be feasible.
The main function of the slingers is to store oil in their rims and push it under some pressure or head into the crank pins. The removal of particles from the oil supply is a secondary function which would not have been unintended, as another motorcycle of that era had slingers that did not do this. Slingers do not have to trap particles.
... I am curious about the height of the outer lip in relation to the oil exit hole. Was there to be more oil flowing into the slingers so some would over flow the lips? The devise is called a slinger. It makes me wonder if the intent was to over fill it so oil would then be slung off to lubricate the cam, lifters, etc.... Has anyone ever examined the path or aim of splatter?... As it looks to me, maybe some was intended to over flow for slinging...
The slinger was designed to receive and hold more oil than could be taken by the hole into the crank pin. The slinger must overflow enough so that there will always be oil covering the hole into the crankpin.
But the slingers are located on the ends of the crank outside the webs, confined by the case where I don't think the overflow can by slung to lubricate the rest of the crankcase. Slinging just refers to what happens to the oil in the slingers, not outside the slingers.
You are referring to the "flinging" that occurs after the "slung" oil goes into the crank pins and out through the rod bearings. After passing through the slingers, into the crank pins and out of the rod bearings, the oil is then flung off the throws to the interior of the crankcase. This lubricates one of the piston skirts (because of direction of rotation), the camshaft and lifters, and travels along the pushrods into the heads.
Much of what is collected in the slingers would have been drained out each oil change if it made it back to the pan... To me the volume of particles captured are not really that much. Does it really matter to trap them? Trapping that little, does it really add to the longevity of the bearings and crank?...
I think it takes a heaping tablespoon of particles to fill each slinger. I does seem desirable to remove that much material as soon as possible from circulation. Without the slinger traps, I don't know if the material would all settle and stay in one place, or whether at least some of it would be continually picked up and recirculated, or how much would eventually be removed by oil changes.
If there were no slingers, then when a timing gear is wearing, or a valve guide is disintegrating, or a tappet face is pitting, the particles that are normally quickly caught by the slingers would continue to circulate and wear the bearings and cylinders, at least until the engine was shut off. It does seem that slingers add to the longevity of the motor.
The main function of the slingers is to store oil in their rims and push it under some pressure or head into the crank pins. The removal of particles from the oil supply is a secondary function which would not have been unintended, as another motorcycle of that era had slingers that did not do this. Slingers do not have to trap particles.
... I am curious about the height of the outer lip in relation to the oil exit hole. Was there to be more oil flowing into the slingers so some would over flow the lips? The devise is called a slinger. It makes me wonder if the intent was to over fill it so oil would then be slung off to lubricate the cam, lifters, etc.... Has anyone ever examined the path or aim of splatter?... As it looks to me, maybe some was intended to over flow for slinging...
The slinger was designed to receive and hold more oil than could be taken by the hole into the crank pin. The slinger must overflow enough so that there will always be oil covering the hole into the crankpin.
But the slingers are located on the ends of the crank outside the webs, confined by the case where I don't think the overflow can by slung to lubricate the rest of the crankcase. Slinging just refers to what happens to the oil in the slingers, not outside the slingers.
You are referring to the "flinging" that occurs after the "slung" oil goes into the crank pins and out through the rod bearings. After passing through the slingers, into the crank pins and out of the rod bearings, the oil is then flung off the throws to the interior of the crankcase. This lubricates one of the piston skirts (because of direction of rotation), the camshaft and lifters, and travels along the pushrods into the heads.
Much of what is collected in the slingers would have been drained out each oil change if it made it back to the pan... To me the volume of particles captured are not really that much. Does it really matter to trap them? Trapping that little, does it really add to the longevity of the bearings and crank?...
I think it takes a heaping tablespoon of particles to fill each slinger. I does seem desirable to remove that much material as soon as possible from circulation. Without the slinger traps, I don't know if the material would all settle and stay in one place, or whether at least some of it would be continually picked up and recirculated, or how much would eventually be removed by oil changes.
If there were no slingers, then when a timing gear is wearing, or a valve guide is disintegrating, or a tappet face is pitting, the particles that are normally quickly caught by the slingers would continue to circulate and wear the bearings and cylinders, at least until the engine was shut off. It does seem that slingers add to the longevity of the motor.
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Darryl.Richman
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Proposal for Self Cleaning Slinger Rings
I would agree with Allan's point of view. BMW used this means of oiling the engine since they started in 1923. In 1936, with the introduction of the R5 and the first "tunnel cast" motors, BMW made a design change to add the separate sheet metal slingers.
Previously, the equivalent function was performed by a groove that was machined into the outside faces of the outer crank webs. This machined groove passed over and through the capped ends of the crank pins. Therefore, oil that passed through the main bearings and into this groove then fell into the crank pin.
There can be no particulate capture in this system. So it would seem that BMW did have it in mind to use the slingers as a material trap.
Here are two pictures from the crank on my 1928 R52. The first is the front web. You can see the groove I'm talking about and how it would continue through the crank pin end.
The second photo shows the removed crank pin. This pin is not an original one, but a replacement, and that is why the groove cutout doesn't really match the groove in the web closely. (You can also tell by the fact that it doesn't have the small matching semicircles with the ones visible above; when BMW assembled these cranks, they locked the pins in place by drilling small holes on either side of the pin through the seam and then drove locking pins into those holes. No engine restorer seems to follow this principle today.)
Previously, the equivalent function was performed by a groove that was machined into the outside faces of the outer crank webs. This machined groove passed over and through the capped ends of the crank pins. Therefore, oil that passed through the main bearings and into this groove then fell into the crank pin.
There can be no particulate capture in this system. So it would seem that BMW did have it in mind to use the slingers as a material trap.
Here are two pictures from the crank on my 1928 R52. The first is the front web. You can see the groove I'm talking about and how it would continue through the crank pin end.
The second photo shows the removed crank pin. This pin is not an original one, but a replacement, and that is why the groove cutout doesn't really match the groove in the web closely. (You can also tell by the fact that it doesn't have the small matching semicircles with the ones visible above; when BMW assembled these cranks, they locked the pins in place by drilling small holes on either side of the pin through the seam and then drove locking pins into those holes. No engine restorer seems to follow this principle today.)
--Darryl Richman
Proposal for Self Cleaning Slinger Rings
Darryl,
Thank you for posting the R52 shots. It is interesting to know that they had the bottom of the groove feeding into the oil holes and no reserve area for particles. Does the R52 have the same problem with the groove filling with particles over time? Or do they remain clean?
What is the orientation of the crankpin hole? Does it always remain down? Say at the 180 degree mark?
Thank you for posting the R52 shots. It is interesting to know that they had the bottom of the groove feeding into the oil holes and no reserve area for particles. Does the R52 have the same problem with the groove filling with particles over time? Or do they remain clean?
What is the orientation of the crankpin hole? Does it always remain down? Say at the 180 degree mark?
Ole Guy
1954 R51/3
1954 R51/3
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Darryl.Richman
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Proposal for Self Cleaning Slinger Rings
I have worked on three motors from this era, the R52 pictured, an R62 and an R12. None of them had any build up of crud in the groove, but both the R12 and R52 had clearly been openned up before.
I'm not sure exactly what you're asking about the crankpin hole. The cutaway part in the photo faces the center of rotation of the crank. On the rear face, the pin is open, and an interference fit plug is installed to keep oil inside the pin. In the photo below, you can see one of the plugs above the left pin, and you can see through that pin. If you look at the center crank web, on the left side, you can see the new plug installed.
There's a small hole drilled through the side of the pin where the bearing normally runs, on what is the outside of the circle the pin makes as it revolves. The centripital force pushes oil through this feed hole and into the conrod bearing. It then "leaks" out from either side of the conrod big end and is flung around the crankcase interior.
The conrod little end has, in fact, two small openings just on either side where the rod comes in, and these have matching holes in the piston pin bushing. So, some of the oil flung out from the big end lands in these holes and keeps the piston pin bushing oiled.
I'm not sure exactly what you're asking about the crankpin hole. The cutaway part in the photo faces the center of rotation of the crank. On the rear face, the pin is open, and an interference fit plug is installed to keep oil inside the pin. In the photo below, you can see one of the plugs above the left pin, and you can see through that pin. If you look at the center crank web, on the left side, you can see the new plug installed.
There's a small hole drilled through the side of the pin where the bearing normally runs, on what is the outside of the circle the pin makes as it revolves. The centripital force pushes oil through this feed hole and into the conrod bearing. It then "leaks" out from either side of the conrod big end and is flung around the crankcase interior.
The conrod little end has, in fact, two small openings just on either side where the rod comes in, and these have matching holes in the piston pin bushing. So, some of the oil flung out from the big end lands in these holes and keeps the piston pin bushing oiled.
--Darryl Richman
Proposal for Self Cleaning Slinger Rings
Darryl,
Never mind about the crank hole. I framed that question before thinking and I know the answer. I am tired after very long drive.
The slinger sludge is what I am really wondering about. The pictures are illustrating hard packed particles. They accumulate over a very long time through many cycles of running, setting up to dry, etc. Centrifugal action compacts it, chemicals (I guess varnish) fuse or bond them almost like epoxy. Then the rims fill and the migration into the oil holes starts. Is this clog and build up over time or a sudden clump falling loose and into the hole? Maybe just both I suppose.
I wish I had a better understanding of these particles. I can only draw inferences from the photos. It looks like powder of some sort. Are any of them larger pieces? Or is mostly fused powder size?
I would really be interested knowing how they manage to pack up in the oil holes. It seems powder size particles would simply flow through. If they are splintered particles I could begin to see why they might form a dam such as powdered aluminum particles do in radiator sealants.
Then I can’t help but think if this stuff was never allowed to collect in the slingers, then it could never form and oil dam in the oil holes. So that brings me back to the idea of either eliminating the extra depth in the slinger rim or place something to keep the particles agitated so they continually move along. Vech’s idea of an external oil filter would then handle the oil clean up.
To sum it up, don’t let the particles accumulate in the slingers, so an oil dam never happens. Then filter the oil to maximize engine longevity.
My thinking there is a life cycle to engine contaminates. A single particle moves into the oil, then another, etc. Somehow they must stick together and form deposits and bigger pieces. Detergents try to prevent this and to date do a good job of it. Frequent oil changes greatly help to remove contaminates. Letting an engine sit for a long time gives contaminates time to dry and stick where they rest. The slingers are prime examples. My thinking is to eliminate this collection area to prevent slinger crud and resulting oil dam.
Other engine builders have proven simply changing the oil is sufficient in engines without oil filters. Their cranks and bearings hang in there.
I am still hopeful this combination is possible. I do agree contaminates are not healthy circulating and believe frequent oil changes address that. The next step here it preventing the oil dams and keeping the slingers clean will address that. This is why I am asking about the life cycle of a particle and how they manage to form an oil dam. As it is the explanation is slow migration. If the slingers were kept clean, would an oil dam still occur? Are today’s detergent oil enough?
Never mind about the crank hole. I framed that question before thinking and I know the answer. I am tired after very long drive.
The slinger sludge is what I am really wondering about. The pictures are illustrating hard packed particles. They accumulate over a very long time through many cycles of running, setting up to dry, etc. Centrifugal action compacts it, chemicals (I guess varnish) fuse or bond them almost like epoxy. Then the rims fill and the migration into the oil holes starts. Is this clog and build up over time or a sudden clump falling loose and into the hole? Maybe just both I suppose.
I wish I had a better understanding of these particles. I can only draw inferences from the photos. It looks like powder of some sort. Are any of them larger pieces? Or is mostly fused powder size?
I would really be interested knowing how they manage to pack up in the oil holes. It seems powder size particles would simply flow through. If they are splintered particles I could begin to see why they might form a dam such as powdered aluminum particles do in radiator sealants.
Then I can’t help but think if this stuff was never allowed to collect in the slingers, then it could never form and oil dam in the oil holes. So that brings me back to the idea of either eliminating the extra depth in the slinger rim or place something to keep the particles agitated so they continually move along. Vech’s idea of an external oil filter would then handle the oil clean up.
To sum it up, don’t let the particles accumulate in the slingers, so an oil dam never happens. Then filter the oil to maximize engine longevity.
My thinking there is a life cycle to engine contaminates. A single particle moves into the oil, then another, etc. Somehow they must stick together and form deposits and bigger pieces. Detergents try to prevent this and to date do a good job of it. Frequent oil changes greatly help to remove contaminates. Letting an engine sit for a long time gives contaminates time to dry and stick where they rest. The slingers are prime examples. My thinking is to eliminate this collection area to prevent slinger crud and resulting oil dam.
Other engine builders have proven simply changing the oil is sufficient in engines without oil filters. Their cranks and bearings hang in there.
I am still hopeful this combination is possible. I do agree contaminates are not healthy circulating and believe frequent oil changes address that. The next step here it preventing the oil dams and keeping the slingers clean will address that. This is why I am asking about the life cycle of a particle and how they manage to form an oil dam. As it is the explanation is slow migration. If the slingers were kept clean, would an oil dam still occur? Are today’s detergent oil enough?
Ole Guy
1954 R51/3
1954 R51/3