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Cylinder lubrication of small unaflows'?
Posted by: Garry Hunsaker (IP Logged)
Date: April 11, 2002 03:05PM
<HTML>I have been rummaging around in the 1936 11th edition of Kents book on Power I have. My opinion of this text rises daily. Especially in that it quotes the original sources for its data. The one thing I am noticing though, in all of the sources I am looking at, is what data is available all deals with ‘really’ big power plants.
An example is the note on high temperature steam engine lubrication; section 7-17 of Kent.
“In engines using high-temperature steam (700 to 800 F), the cylinder oil is actually vaporized by the heat of the steam, but if the viscosity is high enough, some oil remains on the surfaces until a fresh supply is injected. If ‘too much’ oil is supplied, it “cracks” and forms carbon deposits which cause increased heating and wear. In large engines with steam at 700 F., 7 drops of cylinder oil per minute to each end of each cylinder. 6 drops in each valve, and 5 drops in each packing case have been found to give good lubrication while avoiding carbon.”
Some where, and I think it is in Kent again, there is mention that unaflow cylinders require ‘direct’ lubrication of the walls do to the effect of the ports sweeping the cylinder clean of lubricant. (You think I would eventually learn to take notes when I am reading. :)
What I am getting at here is it necessary on small unaflows to provide lubrication to the cylinder wall itself? I still intend to use piston valves, as I do not trust my ability to design a double beat poppet valve, and pushing into the William’s cycle arena I think is better left to later experiment and lots of bench testing. Keeping piston valves alive at 700 F, give or take a bit, will be interesting enough. I figure with using Garelock 98 (again thanks Jim) for rod packing, even what little oil vapor is being deposited on the rod, should keep things below the ‘self destruction’ threshold in that area.
I am wondering if some of the newer ‘synthetic’ lubricants, as Jim Crank pointed out some folks are using in their steamers, will be less prone to vaporization, and let me get away with only injecting cylinder oil directly onto the piston valves rings?
Admittedly, all of this depends on what material you make the cylinder walls out of. A fine grade of grey cast iron is easier to hold lubricant on than say 4160 chromoly. Though the later does have some nice strength characteristics at higher temps and might allow for lighter components. Then of course you get into the choice of piston ring material to match what your doing with the cylinder..... My isn’t all this steam design stuff fun; I figure this migraine should stop in another year or two :)
My best guess of all of this is so little work has been done on small high pressure and temperature steam plants, that most of this is take your best shot, build the dang thing, and see what breaks first.
Hmmm???
Garry
PS: I think my best shot is to stay out of ebay for awhile, and complete my back issiues of the ‘Steam Automobile Bulletin”.</HTML>
An example is the note on high temperature steam engine lubrication; section 7-17 of Kent.
“In engines using high-temperature steam (700 to 800 F), the cylinder oil is actually vaporized by the heat of the steam, but if the viscosity is high enough, some oil remains on the surfaces until a fresh supply is injected. If ‘too much’ oil is supplied, it “cracks” and forms carbon deposits which cause increased heating and wear. In large engines with steam at 700 F., 7 drops of cylinder oil per minute to each end of each cylinder. 6 drops in each valve, and 5 drops in each packing case have been found to give good lubrication while avoiding carbon.”
Some where, and I think it is in Kent again, there is mention that unaflow cylinders require ‘direct’ lubrication of the walls do to the effect of the ports sweeping the cylinder clean of lubricant. (You think I would eventually learn to take notes when I am reading. :)
What I am getting at here is it necessary on small unaflows to provide lubrication to the cylinder wall itself? I still intend to use piston valves, as I do not trust my ability to design a double beat poppet valve, and pushing into the William’s cycle arena I think is better left to later experiment and lots of bench testing. Keeping piston valves alive at 700 F, give or take a bit, will be interesting enough. I figure with using Garelock 98 (again thanks Jim) for rod packing, even what little oil vapor is being deposited on the rod, should keep things below the ‘self destruction’ threshold in that area.
I am wondering if some of the newer ‘synthetic’ lubricants, as Jim Crank pointed out some folks are using in their steamers, will be less prone to vaporization, and let me get away with only injecting cylinder oil directly onto the piston valves rings?
Admittedly, all of this depends on what material you make the cylinder walls out of. A fine grade of grey cast iron is easier to hold lubricant on than say 4160 chromoly. Though the later does have some nice strength characteristics at higher temps and might allow for lighter components. Then of course you get into the choice of piston ring material to match what your doing with the cylinder..... My isn’t all this steam design stuff fun; I figure this migraine should stop in another year or two :)
My best guess of all of this is so little work has been done on small high pressure and temperature steam plants, that most of this is take your best shot, build the dang thing, and see what breaks first.
Hmmm???
Garry
PS: I think my best shot is to stay out of ebay for awhile, and complete my back issiues of the ‘Steam Automobile Bulletin”.</HTML>
Re: Cylinder lubrication of small unaflows'?
Posted by: Jim Crank (IP Logged)
Date: April 11, 2002 04:57PM
<HTML>Garry, et al,
If anybody knows FOR SURE of a cylinder oil that is not going to come apart at 750°F I wish they would speak up. The oil I have used in the White and the Doble is Mobile Super Extra Hecla Superheat Steam Cylinder Oil.
I tried both their mineral version and the crude oil based version. Nothing squeaks and it does separate out in the water tank overnight for easy flushing.
I hear that Mobile One gear oil has been used; but nothing more. No real proof at all.
And, there is a huge difference between what works in a Stanley and what works in a piston valve engine. Stanley oils are death in a superheat piston valve engine.
Just because the superheater outlet says 750 doesn't mean the engine cylinders are anywhere near that temperature, more like 100-125°F lower. I mean an oil that does not carbonize at a real 750° cylinder temperature.
The engines you mention are huge things with 3' to 5' strokes and do have wall injection ports, I have seen them. In a small car sized engine I would think that steam line injection is fine. It does seem to work.
Now, do you want the oil atomized in the line first, or do you want real liquid oil on the piston rings? Does it matter?
When Doble and Besler tried to run their engines at 850°-900°F, the valve rings went away fast, oil or no oil!! Both had to drop to 750° for any ring life on the valves. One reason to use poppet valves.
OK, the turbine investigation just came to a grinding halt, my consultant said that none are really suitable and forget it.
So now I am in the same boat as you are, back to the Wankel and now there are oil questions that need to be solved. Put it in for seal life and try like mad to get it all out before it coats the condenser and ruins the heat transfer, or go to the older Mazda carbon seals and try to make it live without oil?
You are certainly right, no one since the Doble days has really gone into this lubrication question and it needs to be answered for sure.
Maybe we should switch to gas turbines!
Oh, the fun of steam car design!!
Jim</HTML>
If anybody knows FOR SURE of a cylinder oil that is not going to come apart at 750°F I wish they would speak up. The oil I have used in the White and the Doble is Mobile Super Extra Hecla Superheat Steam Cylinder Oil.
I tried both their mineral version and the crude oil based version. Nothing squeaks and it does separate out in the water tank overnight for easy flushing.
I hear that Mobile One gear oil has been used; but nothing more. No real proof at all.
And, there is a huge difference between what works in a Stanley and what works in a piston valve engine. Stanley oils are death in a superheat piston valve engine.
Just because the superheater outlet says 750 doesn't mean the engine cylinders are anywhere near that temperature, more like 100-125°F lower. I mean an oil that does not carbonize at a real 750° cylinder temperature.
The engines you mention are huge things with 3' to 5' strokes and do have wall injection ports, I have seen them. In a small car sized engine I would think that steam line injection is fine. It does seem to work.
Now, do you want the oil atomized in the line first, or do you want real liquid oil on the piston rings? Does it matter?
When Doble and Besler tried to run their engines at 850°-900°F, the valve rings went away fast, oil or no oil!! Both had to drop to 750° for any ring life on the valves. One reason to use poppet valves.
OK, the turbine investigation just came to a grinding halt, my consultant said that none are really suitable and forget it.
So now I am in the same boat as you are, back to the Wankel and now there are oil questions that need to be solved. Put it in for seal life and try like mad to get it all out before it coats the condenser and ruins the heat transfer, or go to the older Mazda carbon seals and try to make it live without oil?
You are certainly right, no one since the Doble days has really gone into this lubrication question and it needs to be answered for sure.
Maybe we should switch to gas turbines!
Oh, the fun of steam car design!!
Jim</HTML>
Re: Cylinder lubrication of small unaflows'?
Posted by: Peter Heid (IP Logged)
Date: April 11, 2002 05:02PM
<HTML>Gary,
One of the best features of synthetic oils is the extended temperature range of operation. The molacules are engineered for the job, including viscosity. Mineral oils are refined to meet a range of viscosities and then stabilizers are added to make the oil meet a specific grade. The stabilizers are the lightest fraction and boil off first, leaving oil of the wrong viscosity to do the job. I have seen the cylinder and valve oilers used on unaflow engines instead of injecting it into the steam flow and the same reasons were listed you found but only on large engines compaired to that which you might use in an auto. Cylinder walls electrofusion plated with nickle-silicon-carbide have a finish similar to cast iron and being a ground surface, the finish can be varied to suit the rings used. Nikisil coatings do not wear and they have proven themselves reliable for more than 20 years. The plated bore should have less than 0.0002 inches out of round or taper and modern rings are lapped to the bore size before plating for an almost perfect fit when new. An IC engine using nikisil bores should be assembled with no oil on the cylinder bore or piston for proper break-in. My first attempt will be chrome rings in nikisil bores and see how long things last, they are materials suited for use together and sealing is not an issue. Wish me luck.
Peter Heid</HTML>
One of the best features of synthetic oils is the extended temperature range of operation. The molacules are engineered for the job, including viscosity. Mineral oils are refined to meet a range of viscosities and then stabilizers are added to make the oil meet a specific grade. The stabilizers are the lightest fraction and boil off first, leaving oil of the wrong viscosity to do the job. I have seen the cylinder and valve oilers used on unaflow engines instead of injecting it into the steam flow and the same reasons were listed you found but only on large engines compaired to that which you might use in an auto. Cylinder walls electrofusion plated with nickle-silicon-carbide have a finish similar to cast iron and being a ground surface, the finish can be varied to suit the rings used. Nikisil coatings do not wear and they have proven themselves reliable for more than 20 years. The plated bore should have less than 0.0002 inches out of round or taper and modern rings are lapped to the bore size before plating for an almost perfect fit when new. An IC engine using nikisil bores should be assembled with no oil on the cylinder bore or piston for proper break-in. My first attempt will be chrome rings in nikisil bores and see how long things last, they are materials suited for use together and sealing is not an issue. Wish me luck.
Peter Heid</HTML>
Re: Cylinder lubrication of small unaflows'?
Posted by: Garry Hunsaker (IP Logged)
Date: April 11, 2002 11:03PM
<HTML>Wow Peter
What kind of machine tools are you using to hold these kinds of cylinder tolerances? I am seeing new engine lathes bragging they can hold a tolerance of .0004 at four inches from the head. .0002 is reaching beyond the edge of what I can even feel with hand mikes. It would seem to me, if you are looking at a double acting design, your cross head and cylinder would have to be turned as one, not to mention an utterly straight piston rod. Depending on what type of engine you are looking at, won’t you have to take into account the differences in expansion in a hot cylinder versus cold? I have heard that some of the big marine unaflows actually machined their cylinders into a barrel shape to compensate for the tapering effect of heat expansion at the head end versus the cooler exhaust ports.(I would love to know how they did that)
Your choice of ‘electrofusion plated nickle-silicon-carbide’ seems almost science fiction to me. Though if this works, it will be the only steamer in history the lower end wears out years before the rings do!
I definitely wish you luck with this. Your stepping into places I have never heard of.
Which brings me to the question, where can I find info on some of these new materials and processes. Someone mentioned earlier, was it George Nutz, about an insulative ceramic coating for the piston and cylinder head faces. The idea of slowing down heat transfer on both these surfaces has considerable merit. I believe in the same note there was mention of a lithium coating that apparently did a good job of sealing the piston rings. I am no chemist, but I was of the impression lithium reacted with just about everything when it gets hot and is around moisture. Is this some kind of alloy?
I guess it’s the old story.
The more I learn, the less I know.
Garry</HTML>
What kind of machine tools are you using to hold these kinds of cylinder tolerances? I am seeing new engine lathes bragging they can hold a tolerance of .0004 at four inches from the head. .0002 is reaching beyond the edge of what I can even feel with hand mikes. It would seem to me, if you are looking at a double acting design, your cross head and cylinder would have to be turned as one, not to mention an utterly straight piston rod. Depending on what type of engine you are looking at, won’t you have to take into account the differences in expansion in a hot cylinder versus cold? I have heard that some of the big marine unaflows actually machined their cylinders into a barrel shape to compensate for the tapering effect of heat expansion at the head end versus the cooler exhaust ports.(I would love to know how they did that)
Your choice of ‘electrofusion plated nickle-silicon-carbide’ seems almost science fiction to me. Though if this works, it will be the only steamer in history the lower end wears out years before the rings do!
I definitely wish you luck with this. Your stepping into places I have never heard of.
Which brings me to the question, where can I find info on some of these new materials and processes. Someone mentioned earlier, was it George Nutz, about an insulative ceramic coating for the piston and cylinder head faces. The idea of slowing down heat transfer on both these surfaces has considerable merit. I believe in the same note there was mention of a lithium coating that apparently did a good job of sealing the piston rings. I am no chemist, but I was of the impression lithium reacted with just about everything when it gets hot and is around moisture. Is this some kind of alloy?
I guess it’s the old story.
The more I learn, the less I know.
Garry</HTML>
Re: Cylinder lubrication of small unaflows'?
Posted by: Peter Brow (IP Logged)
Date: April 12, 2002 06:35AM
<HTML>Peter Barrett and the folks behind the Mobile Steam Society steam VW reportedly arranged to have a special batch of non-detergent Mobil One motor oil made up for steam experimental purposes. Last I heard, that batch is gone. Peter Barrett used it in several of his engines, PS77 types, which had short life due to not injecting oil into the cylinders. This attempt at splash lubed cylinders failed. He did state that this oil went straight through the condenser with no clogging.
In the classic steamers, oil seems to vaporize into the steam, then condenses on the steamed wear surfaces in engine, which tend to run at around 500°F. The 1936 Kent (I have the same edition) says that the limiting steam temperature then was about 750°F, and, alas, that still seems to be the state of the art.
The way to increase engine temp may be to arrange batch production of some special non-detergent hi-temp synthetic motor oil. There are several small producers of specialty synthetic oil who might agree to help. It might be as simple as diverting a barrel or two off the production line upline from the detergent addition stage. Maybe a bunch of us could kick in on a batch, if we could agree on a temperature range. Some of the synthetic oils can run at eye-popping temperatures.
Bummer on the turbine, Jim. Many of my steam ideas may be stuck in the 1920s for now, but I would love to see a good running steam turbine in a car. No oil, no valves, no nutt'n. It may happen yet. Anyway, the upside of "forget it" type experiences (of which I have had several zillion) is that it helps you zero in on what you finally build, so it is always a step ahead. This is the advantage of working on 2 or more ideas at a time; always a backup idea (Wankel) to go to when the other idea doesn't pan out.
I think the lithium coating is a lithium _compound_, Garry. If you plated the innards of a steam cylinder with pure lithium, you could just shut off the boiler and run the engine on water injection ... for a while! LOL.
Peter</HTML>
In the classic steamers, oil seems to vaporize into the steam, then condenses on the steamed wear surfaces in engine, which tend to run at around 500°F. The 1936 Kent (I have the same edition) says that the limiting steam temperature then was about 750°F, and, alas, that still seems to be the state of the art.
The way to increase engine temp may be to arrange batch production of some special non-detergent hi-temp synthetic motor oil. There are several small producers of specialty synthetic oil who might agree to help. It might be as simple as diverting a barrel or two off the production line upline from the detergent addition stage. Maybe a bunch of us could kick in on a batch, if we could agree on a temperature range. Some of the synthetic oils can run at eye-popping temperatures.
Bummer on the turbine, Jim. Many of my steam ideas may be stuck in the 1920s for now, but I would love to see a good running steam turbine in a car. No oil, no valves, no nutt'n. It may happen yet. Anyway, the upside of "forget it" type experiences (of which I have had several zillion) is that it helps you zero in on what you finally build, so it is always a step ahead. This is the advantage of working on 2 or more ideas at a time; always a backup idea (Wankel) to go to when the other idea doesn't pan out.
I think the lithium coating is a lithium _compound_, Garry. If you plated the innards of a steam cylinder with pure lithium, you could just shut off the boiler and run the engine on water injection ... for a while! LOL.
Peter</HTML>
Re: Cylinder lubrication of small unaflows'?
Posted by: Jim Crank (IP Logged)
Date: April 12, 2002 01:41PM
<HTML>Gary,
If Peter is using the same machining technology I am, then we use a Sunnen hone to do the final sizing.
Definitely the cylinder bore and the crosshead guide bore are as concentric as possible. That goes without saying.
Jim</HTML>
If Peter is using the same machining technology I am, then we use a Sunnen hone to do the final sizing.
Definitely the cylinder bore and the crosshead guide bore are as concentric as possible. That goes without saying.
Jim</HTML>
Re: Cylinder lubrication of small unaflows'?
Posted by: Jim Crank (IP Logged)
Date: April 12, 2002 01:49PM
<HTML>Peter,
Thanks for the words of comfort re the turbine. It is that old problem of trying for a wide high efficency curve so the part load efficiency is at least acceptable. No turbine will do this.
Now that I am back with the Wankel, and have to make iron chambers for steam, I am wondering too about surface coatings. Mazda hard chromes them. For steam there may be something better in combination with either their old carbon apex seals or the new racing ceramic seals.
If any of you guys do try to get some super duper synthetic oil compounded, count me in for a 20 gallon barrel.
Jim</HTML>
Thanks for the words of comfort re the turbine. It is that old problem of trying for a wide high efficency curve so the part load efficiency is at least acceptable. No turbine will do this.
Now that I am back with the Wankel, and have to make iron chambers for steam, I am wondering too about surface coatings. Mazda hard chromes them. For steam there may be something better in combination with either their old carbon apex seals or the new racing ceramic seals.
If any of you guys do try to get some super duper synthetic oil compounded, count me in for a 20 gallon barrel.
Jim</HTML>
Re: Cylinder lubrication of small unaflows'?
Posted by: George K. Nutz (IP Logged)
Date: April 12, 2002 02:40PM
<HTML>Gary,
It had been mentioned quite a while back that Rod Teel's slide valve engine(running on the Lamont) had TAFA-PRAXAIR plasma arc sprayed molybdenum coatings on the valves---coating quite hard and slippery. It had been mentioned that modern dragsters were using this coating on exhaust valve stems and piston rings on these huge horsepower engines that prevented seizing under such high temperatures, it was mentioned that the rings would seat in very quickly with this coating. Unfortunately no steam engine bore is circular, with a slide or piston valve the bore deforms(grows) due to the much higher temperature on the admission side than the "outside of the bore. Skinner used to barrel bore their big unaflows so that when hot would be more constant in circular bore dimensions from the cylinder ends to the unaflow ports. You have a good memory, it was a post looong ago!!
Best, George</HTML>
It had been mentioned quite a while back that Rod Teel's slide valve engine(running on the Lamont) had TAFA-PRAXAIR plasma arc sprayed molybdenum coatings on the valves---coating quite hard and slippery. It had been mentioned that modern dragsters were using this coating on exhaust valve stems and piston rings on these huge horsepower engines that prevented seizing under such high temperatures, it was mentioned that the rings would seat in very quickly with this coating. Unfortunately no steam engine bore is circular, with a slide or piston valve the bore deforms(grows) due to the much higher temperature on the admission side than the "outside of the bore. Skinner used to barrel bore their big unaflows so that when hot would be more constant in circular bore dimensions from the cylinder ends to the unaflow ports. You have a good memory, it was a post looong ago!!
Best, George</HTML>
Re: Cylinder taper
Posted by: C Benson (IP Logged)
Date: April 12, 2002 02:43PM
<HTML>Old trick on Indian m/c racers,,,1920,,,I did it in 1970,,,,Hone the middle an' lower part of bore +.0005--.0010 leaves the top to expand to size when running,,,Watch the temp of everythin,, includin your sweaty lil hands ,mikes,, an all ....Ya can hone up to .010'' after that it aint worth the time/effort Cheers Ben</HTML>
Re: Cylinder taper
Posted by: George K. Nutz (IP Logged)
Date: April 12, 2002 03:52PM
<HTML>Coburn,
Very wise words as usual! As an amatuer machinest ws taught how to hold a micrometer with pinky and not "grow" the mike as I am measuring---also never keep the micrometer on top of the lathe gearbox. When turning, say, a 2 inch shaft and it is getting to a higher temperature than the surroundings touch the shaft(lathe off) and if it is warm to the hands estimate its temperature compared to shop temperature-- if 40 degree differential could read .0008 bigger than the next morning!! The wisdom of you "old timers", no wonder your motorcycles were so blazing fast and confused the competition!! And then we get back to the problem of a steam cylinder bore becoming a quasi- oblate circle under hard running---why can't we come up with a zero expansion, infinitely strong, easily machinable material---
maybe ceramic engines are the answere. After all of this we will return to sand as the ideal material!!! ;o) , George(with sweaty lil hands)</HTML>
Very wise words as usual! As an amatuer machinest ws taught how to hold a micrometer with pinky and not "grow" the mike as I am measuring---also never keep the micrometer on top of the lathe gearbox. When turning, say, a 2 inch shaft and it is getting to a higher temperature than the surroundings touch the shaft(lathe off) and if it is warm to the hands estimate its temperature compared to shop temperature-- if 40 degree differential could read .0008 bigger than the next morning!! The wisdom of you "old timers", no wonder your motorcycles were so blazing fast and confused the competition!! And then we get back to the problem of a steam cylinder bore becoming a quasi- oblate circle under hard running---why can't we come up with a zero expansion, infinitely strong, easily machinable material---
maybe ceramic engines are the answere. After all of this we will return to sand as the ideal material!!! ;o) , George(with sweaty lil hands)</HTML>
Re: Cylinders / Rings
Posted by: Peter Heid (IP Logged)
Date: April 12, 2002 06:42PM
<HTML>I have seen several engines taper bored to accomadate for uneven thermal expansion and cylinder wall thickness engineered to do the same. There is no perfect material but we can effectively work with what we have. Modern IC exhaust valves have a 0.00075 to 0.001 inch stem taper to allow for the difference in expansion from the hot to the cold end. The crown of an IC piston is slightly reduced near the top to accomadate for thermal expansion differences also.
The companies that do nickle-silicon-carbide coatings grind the surface with special equiptment, they use to spin the work while grinding, I don't know if that is still done that way, but a 4 cylinder engine block swinging around looked dangerous. A sunnen precision hone will barely touch the coating, only very hard grinding materials like diamonds can influence the finish. The platers have fantastic precision at very reasonable costs and the only time we see damage to the surface is when broken parts lodge in the ports and break the metal under the coating.
Stelite piston rings can take 1200 degrees F. and those of inconel are good for 1600 degrees but when used in these extreme conditions, they should be plasma coated with a carbide or oxide type coating for reduced friction.
Again Cobern says a bundle in so few words.
The measurements for the accuracy I speak of should not be done with an inside micrometer but a actual bore gauge. All measurements should be done at the same constant temperature. Any parts machined should be allowed to cool completely before final machining or measurements are completed.
Peter Heid</HTML>
The companies that do nickle-silicon-carbide coatings grind the surface with special equiptment, they use to spin the work while grinding, I don't know if that is still done that way, but a 4 cylinder engine block swinging around looked dangerous. A sunnen precision hone will barely touch the coating, only very hard grinding materials like diamonds can influence the finish. The platers have fantastic precision at very reasonable costs and the only time we see damage to the surface is when broken parts lodge in the ports and break the metal under the coating.
Stelite piston rings can take 1200 degrees F. and those of inconel are good for 1600 degrees but when used in these extreme conditions, they should be plasma coated with a carbide or oxide type coating for reduced friction.
Again Cobern says a bundle in so few words.
The measurements for the accuracy I speak of should not be done with an inside micrometer but a actual bore gauge. All measurements should be done at the same constant temperature. Any parts machined should be allowed to cool completely before final machining or measurements are completed.
Peter Heid</HTML>
Re: Cylinder lubrication of small unaflows'?
Posted by: Garry Hunsaker (IP Logged)
Date: April 12, 2002 07:53PM
<HTML>[www.morris-lubricants.co.uk]
Morris of England does on line ordering.
Definitely check out their tec info on steam cylinder oils at
[www.morris-lubricants.co.uk]
Garry</HTML>
Morris of England does on line ordering.
Definitely check out their tec info on steam cylinder oils at
[www.morris-lubricants.co.uk]
Garry</HTML>
Re: Cylinder taper/temp
Posted by: C Benson (IP Logged)
Date: April 12, 2002 09:19PM
<HTML>Hey,,Thanks for the comments guys,,,,One I forgot ,,even a 40w lamp at 10--12'' will heat a alloy piston enough to be wrong size WHEN ya get back from ans'' the phone,,,The things I remember,,,Warm the bori'n machine 20min idle,,,Take a light cut to heat the tool in the bar ,,,Forget it if the furnace went off the nite before,,,,See there is a real reason new englanders can get so ugly around autumm ,,,Cheers Ben</HTML>
Re: Cylinder lubrication of small unaflows'?
Posted by: Peter Brow (IP Logged)
Date: April 13, 2002 06:31AM
<HTML>Thanks for the link, Garry.
I recommend reading these tech articles; quite thought-provoking. Many of the oil requirements seem to be contradictory, but give some insight into the reasoning behind the Stanley Motor Carriage Company's recommendation of a lighter straight mineral oil for their condensing systems. The Atlantic graphite oil they recommended was reported to be "a light distillate type oil", and reportedly worked well. Doble was trying ordinary IC motor oil (non-detergent of course, & 30-40W monograde was typical then) in the Doble-Detroit around this time, and claimed 40,000+ miles with minimal wear on his test car in 1916 SAE papers, though this was with relatively low superheat. Some of the comments in Morris tech notes seem to overlook the difference between cylinder wall temp and inlet steam temp, apparently assuming that these are roughly the same. This would be true in steam-jacketed cylinders, but not in ordinary insulated cylinders, where cylinder wall temps have been measured at ~500°F with inlet steam somewhere between 600-700°F, cutoffs in the 28-60% range, clearance volume in the 8-9% range, and typical running pressures ~100-200 psig. (500-600 psig @ boiler). Morris' recommended 5 ppm max oil concentration for feedwater is of interest too.
Peter</HTML>
I recommend reading these tech articles; quite thought-provoking. Many of the oil requirements seem to be contradictory, but give some insight into the reasoning behind the Stanley Motor Carriage Company's recommendation of a lighter straight mineral oil for their condensing systems. The Atlantic graphite oil they recommended was reported to be "a light distillate type oil", and reportedly worked well. Doble was trying ordinary IC motor oil (non-detergent of course, & 30-40W monograde was typical then) in the Doble-Detroit around this time, and claimed 40,000+ miles with minimal wear on his test car in 1916 SAE papers, though this was with relatively low superheat. Some of the comments in Morris tech notes seem to overlook the difference between cylinder wall temp and inlet steam temp, apparently assuming that these are roughly the same. This would be true in steam-jacketed cylinders, but not in ordinary insulated cylinders, where cylinder wall temps have been measured at ~500°F with inlet steam somewhere between 600-700°F, cutoffs in the 28-60% range, clearance volume in the 8-9% range, and typical running pressures ~100-200 psig. (500-600 psig @ boiler). Morris' recommended 5 ppm max oil concentration for feedwater is of interest too.
Peter</HTML>
Re: Cylinder lubrication of small unaflows'?
Posted by: Ron Parola (IP Logged)
Date: April 14, 2002 03:27PM
<HTML>A note on the Nikisil bores : they may be hard BUT I've seen the bores wear through to the aluminum on small 2 strokes. Rotax engines are Nikisil and when they wear out (snowmobiles and such) you have your choice from the factory of a resprayed Nikisil or a iron sleeve, the sleeve is a better deal since it then can be rebored, and I can't say we've found any power difference between the two . Ron P</HTML>
Re: Cylinder lubrication of small unaflows'?
Posted by: Peter Heid (IP Logged)
Date: April 15, 2002 12:18PM
<HTML>Ron,
On a modern IC engine the nikisil bore has a much greater heat transfer rate than a sleeve can ever acheive. The bore will last at least 10:1 over an iron bore in the same conditions and will show no appericable changes in size or wear during its life, unlike iron. Many IC engines would not be able to meet today's emission standards without nikisil or other bore coatings. The emmisions warranty has to go 100,000 miles and a plain iron bore can't do it because of continued wear allowing oil contamination in the combustion chamber. The high speeds of many engines, due to low mass in moving parts, could not be acheived without plated bores because the length of piston skirt may be less than 1/2 of the bore size, only an inch or so wide, thrust loads would wear iron in a matter of hours. Bmw motorcycles have used plated bores since 1985 on 1000cc opposed twin cylinder engines that have 3.700 inch bores and extreme side thrust. Hundreds of thousands of miles later and 17 years, we have never seen a wear problem. My 4 cylinder BMW has 143,500 miles on it and never been apart. How many miles before you see wear ? In all examples with similar milage ? Auto engine bores have to last at least 100,000 miles to meet today's warranty requirements. I think the bores you see warn may be poorly plated because I have seen snowmobiles with 20,000 plus miles not showing any wear and the only time there is a problem is if parts get snagged in the ports. The cost to replate the bore is less than the machining and parts costs to convert it to the wear prone, low heat transfer, iron sleeve, that includes welding and remachining the base metal before replating. The replating and repairs runs about $200.00, far less than buying reconditioned cylinders and the turn around time is less than 7 days. In engines run without oil, the pistons are pressed out of the bores and the aluminum acid etched from the cylinder surfaces before returning to service, how about in iron bores. In our shop nikisil has proven to be the most durable, reliable and easy to repair cylinder surface coating and is far superior to any non plated bore for that purpose.
Peter Heid</HTML>
On a modern IC engine the nikisil bore has a much greater heat transfer rate than a sleeve can ever acheive. The bore will last at least 10:1 over an iron bore in the same conditions and will show no appericable changes in size or wear during its life, unlike iron. Many IC engines would not be able to meet today's emission standards without nikisil or other bore coatings. The emmisions warranty has to go 100,000 miles and a plain iron bore can't do it because of continued wear allowing oil contamination in the combustion chamber. The high speeds of many engines, due to low mass in moving parts, could not be acheived without plated bores because the length of piston skirt may be less than 1/2 of the bore size, only an inch or so wide, thrust loads would wear iron in a matter of hours. Bmw motorcycles have used plated bores since 1985 on 1000cc opposed twin cylinder engines that have 3.700 inch bores and extreme side thrust. Hundreds of thousands of miles later and 17 years, we have never seen a wear problem. My 4 cylinder BMW has 143,500 miles on it and never been apart. How many miles before you see wear ? In all examples with similar milage ? Auto engine bores have to last at least 100,000 miles to meet today's warranty requirements. I think the bores you see warn may be poorly plated because I have seen snowmobiles with 20,000 plus miles not showing any wear and the only time there is a problem is if parts get snagged in the ports. The cost to replate the bore is less than the machining and parts costs to convert it to the wear prone, low heat transfer, iron sleeve, that includes welding and remachining the base metal before replating. The replating and repairs runs about $200.00, far less than buying reconditioned cylinders and the turn around time is less than 7 days. In engines run without oil, the pistons are pressed out of the bores and the aluminum acid etched from the cylinder surfaces before returning to service, how about in iron bores. In our shop nikisil has proven to be the most durable, reliable and easy to repair cylinder surface coating and is far superior to any non plated bore for that purpose.
Peter Heid</HTML>
Re: Cylinder lubrication of small unaflows'?
Posted by: Jim Crank (IP Logged)
Date: April 15, 2002 01:06PM
<HTML>Peter,
Would you also recommend Nikisil coating for the new Wankel iron rotor housings? Mazda used hard chrome originally and it seems to work well in the IC version of the engine.
I would certainly rather replace the seals than the housings.
My racing experience with Nikisil is the same as yours, the best available to date, just as long as it is applied by a competent firm.
Jim</HTML>
Would you also recommend Nikisil coating for the new Wankel iron rotor housings? Mazda used hard chrome originally and it seems to work well in the IC version of the engine.
I would certainly rather replace the seals than the housings.
My racing experience with Nikisil is the same as yours, the best available to date, just as long as it is applied by a competent firm.
Jim</HTML>
Re: Nikasil Wankel
Posted by: Peter Heid (IP Logged)
Date: April 15, 2002 05:24PM
<HTML>Jim,
I think it would be the best choice, if someone can work with the shape of the surface. With today's modern machine tool technology, I don't see why not. Hell, using 9 axis milling machines to make boat props is comon. Any device suitable for a chrome plated wear surface is a canadate for use with nikasil, ring material selection seems far less critical than with any other plated surface I have seen. Tip seals should be no different. Who knows oil requirements may be lessened, the less you use, the less you have to separate.
When some one mentions chrome cylinder plating, I always picture the pocketed, plated bores of a 4 cylinder McCulloch 2 stroke military drone engine used on some autogyros. I think they were 100 CID, big cylinders, something you could really study.
Peter Heid</HTML>
I think it would be the best choice, if someone can work with the shape of the surface. With today's modern machine tool technology, I don't see why not. Hell, using 9 axis milling machines to make boat props is comon. Any device suitable for a chrome plated wear surface is a canadate for use with nikasil, ring material selection seems far less critical than with any other plated surface I have seen. Tip seals should be no different. Who knows oil requirements may be lessened, the less you use, the less you have to separate.
When some one mentions chrome cylinder plating, I always picture the pocketed, plated bores of a 4 cylinder McCulloch 2 stroke military drone engine used on some autogyros. I think they were 100 CID, big cylinders, something you could really study.
Peter Heid</HTML>
Re: Nikasil Wankel
Posted by: Jim Crank (IP Logged)
Date: April 16, 2002 02:43PM
<HTML>Peter,
Thanks for the vote of confidence and I do agree that Nikasil is the best coating.
Not a problem getting the housings made and ground, the outfit in Washington I am working with, they do loads of racing Mazdas, can machine the housings. I have to supply the cast iron new chambers, not a problem.
Porsche also used knurled hard chrome bores on the 1600 Super and 4 cam engines then.
I know the McCullough drone engine. Good for a very short life and then the con rod needle bearings broke up. Jim Dooley was the engineer on this engine and he told me that at that time McCullough wouldn't even answer the phone on questions about using this engine in gyrocopters, nor supply any service info, too much legal mess when they let go. Jim just went ballistic when he heard people were using them that way, said they were too dangerous and never designed for constant use past four hours or so. Said they were a one time use and then shot down.
I had a friend who had a four cylinder one on his copter and it blew up in mid air and put a piece of the rod into his back, putting him in a wheelchair for life.
Jim</HTML>
Thanks for the vote of confidence and I do agree that Nikasil is the best coating.
Not a problem getting the housings made and ground, the outfit in Washington I am working with, they do loads of racing Mazdas, can machine the housings. I have to supply the cast iron new chambers, not a problem.
Porsche also used knurled hard chrome bores on the 1600 Super and 4 cam engines then.
I know the McCullough drone engine. Good for a very short life and then the con rod needle bearings broke up. Jim Dooley was the engineer on this engine and he told me that at that time McCullough wouldn't even answer the phone on questions about using this engine in gyrocopters, nor supply any service info, too much legal mess when they let go. Jim just went ballistic when he heard people were using them that way, said they were too dangerous and never designed for constant use past four hours or so. Said they were a one time use and then shot down.
I had a friend who had a four cylinder one on his copter and it blew up in mid air and put a piece of the rod into his back, putting him in a wheelchair for life.
Jim</HTML>
Re: Test carefully
Posted by: C Benson (IP Logged)
Date: April 17, 2002 07:22PM
<HTML>JIM ,,,,,,U have done many a great servace just now,,,,,,The books are full of success stories they NEVER tell the failures that were responsible for modifin' the cast in stone THEORY !!! Bullett proof walls in the DYNO house,,,Experiment carefully Cheers Ben</HTML>
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