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Post by Roger on May 8, 2021 10:22:08 GMT
That's coming along really nicely. I modified the 'Ewins' type of lubricator to make it shorter. You don't need the additional spacer that's inside the valve body, so that can save a few millimeters. If you need to adjust the delivery, you can change the length of the piston rod instead.
It's interesting to see that you have fed the oil pipe up close to the cylinders. People have tried to convince me that the oil needs to be injected as far upstream as possible to 'atomise' the oil in the steam. This never made any sense so me, because it seems highly unlikely that it will atomise under any circumstances. I've fed mine into the top of the valve chest. Presumably you've tried a number of arrangements on different locomotives. I'd be interested to hear your opinion about this issue. To my way of thinking, the oil is going to get everywhere, even if you tried to prevent that from happening. Steam is rapidly starting, stopping and changing direction. Wherever the Steam goes, oil will surely follow?
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oldnorton
Statesman
5" gauge LMS enthusiast
Posts: 726
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Post by oldnorton on May 8, 2021 10:35:37 GMT
Hi Barry
Yes the Ewins design is a good one.
I have put additional in line non-return valves in mine. In theory, they shouldn't be necessary, but I was getting steam coming back on odd occasions until I fitted a pair.
I did read of a concern that the single drip of oil, as it emerges from the central exit point, might 'on average' get blown one way more than the other because of it always emerging at a predictable point after several piston strokes, and that precision favouring one of the induction cycles. Is this a true effect? Should allow for endless debate over a few cans of beer!
Engine build looks lovely.
Norm
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Post by Roger on May 8, 2021 14:31:06 GMT
Hi Barry Yes the Ewins design is a good one. I have put additional in line non-return valves in mine. In theory, they shouldn't be necessary, but I was getting steam coming back on odd occasions until I fitted a pair. I did read of a concern that the single drip of oil, as it emerges from the central exit point, might 'on average' get blown one way more than the other because of it always emerging at a predictable point after several piston strokes, and that precision favouring one of the induction cycles. Is this a true effect? Should allow for endless debate over a few cans of beer! Engine build looks lovely. Norm Hi Norm, Even if the timing precisely coincided with one point in the cylinder travel, I doubt if an oil drop detaching would be that predictable anyway. The moment of detachment would surely be affected by the temperature at that moment, and the rate that Steam is passing over it. In reality, it's just al likely to cling to the wall and smear out, or come out as a thin thread. In reality, it's not likely to be synchronised to the same spot in the stroke anyway. Oil isn't going to be completely carried away immdiately and lost from the valve chest. It's surely going to line the walls and creep down the passageways. I'm pretty sure it's going to get everywhere, whether you wanted it to or not. This is why practical experience with many different arrangements is of interest. |
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oldnorton
Statesman
5" gauge LMS enthusiast
Posts: 726
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Post by oldnorton on May 8, 2021 14:46:39 GMT
How can any of us prove that the drips will randomly distribute to the left and right? Is it not like putting a tee piece in the pipe, plumbing the outlets to the two cylinders, and trusting that equal amounts of oil will be delivered? There have been discussions about doing that and firm views.
I am not saying Barry is wrong, just 'chatting over a pint' about what might be.
My gut feel is that there will be some bias to the flow, but if it is, say, 49/51 then no problem.
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Post by Roger on May 8, 2021 21:58:25 GMT
How can any of us prove that the drips will randomly distribute to the left and right? Is it not like putting a tee piece in the pipe, plumbing the outlets to the two cylinders, and trusting that equal amounts of oil will be delivered? There have been discussions about doing that and firm views. I am not saying Barry is wrong, just 'chatting over a pint' about what might be. My gut feel is that there will be some bias to the flow, but if it is, say, 49/51 then no problem. It's an interesting thought experiment, and I'd come down on the side of it being pretty much random. Put it this way. If you were designing something to guarantee that there was a bias one way or the other, would you go about it this way? I don't think you would. Oil is likely to end up smeared over every surface, one way or another. I don't think a droplet will detach and then get cleanly carried immediately to its destination, it's likely to be very messy and chaotic. The delivery probably happens over the course of several piston strokes anyway. I imagine it just oozing out of the pipe and coating the pipes or parts of the valve chest, some occasionally being carried along with the Steam. I don't think the process is one of delivery, followed by it mostly going one way. I imagine a coating of oil on most surfaces being drawn slowly but inexorably along with the passing of the steam. Without physically seeing what's going on, or seeing a noticeable difference in delivery to different parts, I don't think any of us can honestly say what's going to happen. Anyway, this is the value of practical experience, someone can tell us if they've encountered any problems. |
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Post by ettingtonliam on May 8, 2021 23:32:47 GMT
i thought that there was an issue years ago with some folks fining that a single oil pump feeding the main stem pipe didn't, for whatever reason, result in equal amounts of oil reaching the cylinders, and that this was the reason why the two cylinder oil pump became popular?
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Post by Roger on May 9, 2021 7:58:37 GMT
i thought that there was an issue years ago with some folks fining that a single oil pump feeding the main stem pipe didn't, for whatever reason, result in equal amounts of oil reaching the cylinders, and that this was the reason why the two cylinder oil pump became popular? That would make sense to me. If you feed oil before a Tee, it's not atomised in my opinion, but just oozes out and runs down the pipe. Trying to make that flow equally to either side of a Tee is not easily achieved unless you can make the pipe absolutely horizontal. This wouldn't be a problem if the oil was atomised. |
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Post by mugbuilder on May 10, 2021 4:44:52 GMT
Some interesting comments about my lubricator arrangement.
I have fitted mechanical lubricators to more than 40 engines over the years and will pass on as many observations as I can remember.
I have found the Ewins type the most reliable if well made. It is important that the 'O'rings are a good fit in the valve body and Viton ones seem to be the best. The pump ram needs to finish its stroke just short of the clack ball as to big a gap can make the pump slow to prime as there is insufficient vacuum produced in the valve chamber on the completion of the up stroke to suck a sufficient amount of thick oil into the chamber. It is best to fill the valve chamber before fitting to the engine or it can take some time before any oil gets to the cylinders. I always make sure that the delivery pipe to the cylinders is full of oil before the final fit up.
The ram must travel far enough above the top 'O' ring to allow enough time for the thick oil to get into the chamber. A scotch crank is better than a spring return for the ram as a spring can place undue strain on the drive, particularly if roller clutches are used.
I am of the opinion that the oil lust oozes out of the delivery hole and is drawn out by the steam flow. The only time that you would get a seperate drop is when the engine has been drifting with no steam long enough for one to form. It generally takes more than one cycle of the pump to form a drop.
I have found that about 20-25 revolutions of the driving wheels is about right for a full cycle of the pump.
It may be good idea to introduce the oil to the steam line as far as is practical from the tee junction provided that this does not require the oil line to run into the smoke box as I have seen engines with this arrangement suffer from burnt carburised oil blocking the delivery pipe. I always have the delivery fitting protrude about half way into the steam line so as not to have the oil just dribble down one side of it. This may help even out the delivery to both sides.
At times I have fitted engines with twin ram pumps when it was impossible to deliver the oil to a common steam pipe. This system works well but is inclined to deliver more oil than needed as pumps with very limited output can be less reliable and slow to prime if the tank runs dry. If a common tank is used then a divider should be included in the tank so that you can see if one pump fails.
Two of my engines have outside piston valve cylinders that could not have oil delivered to a common steam pipe. Both of these have the oil from a single ram pump delivered to a central tee and then to each cylinder. I took care to ensure that the pipes from the tee to each cylinder was of equal length and that the pump provided ample oil to ensure that each cylinder got enough. Too much oil is better than not enough. Every now and then I disconnect both of the oil pipes from the steam delivery pipes and run the engines on compressed air just to make sure that oil comes out of each delivery at the same rate. It does and they are both fit and well.
My oldest engine is now 45 years old and has done close to 2 thousand miles, and has always had the oil delivered to the cylinders via a central steam pipe and tee to each steam chest. I have never seen the valves since they were installed and about ten years ago I removed one front cylinder cover to have a look at how the bore was wearing. I was amazed at the fantastic condition that it was in and had a glaze just like that of a car engine cylinder.
I am not entirely happy with the way that the current job has the steam delivered closer to the right side cylinder than the left, but it was difficult to have it central due to its proximity to the exhaust outlet and the need to have the smoke box fittings accessable. I will ensure that the pump produces enough oil to make up for any shortfall. Anyway i'm not sure that I will physically be able to drive it on a ground level track as the backhead is so far from the rear buffer beam ,so it might just sit in the workshop and look good.
I hope that this is of interest and feel free to disagree with my comments.
Barry
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Post by ettingtonliam on May 10, 2021 6:08:14 GMT
A large mill engine I was involved with many years ago had the oil delivered into the steam pipe via what was called an atomiser. Memory is vague, but I think it had a speen like projection into the steam main, into which the oil was pumped. The idea was that the steam, in passing 'locked' the oil off the spoon and so atomised it. I recall that it was once discovered that the spoon had worn away, and it was necessary to replace it.
Has anything like this ever been tried in minature?
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Post by Roger on May 10, 2021 7:12:03 GMT
Some interesting comments about my lubricator arrangement. I have fitted mechanical lubricators to more than 40 engines over the years and will pass on as many observations as I can remember. I have found the Ewins type the most reliable if well made. It is important that the 'O'rings are a good fit in the valve body and Viton ones seem to be the best. The pump ram needs to finish its stroke just short of the clack ball as to big a gap can make the pump slow to prime as there is insufficient vacuum produced in the valve chamber on the completion of the up stroke to suck a sufficient amount of thick oil into the chamber. It is best to fill the valve chamber before fitting to the engine or it can take some time before any oil gets to the cylinders. I always make sure that the delivery pipe to the cylinders is full of oil before the final fit up. The ram must travel far enough above the top 'O' ring to allow enough time for the thick oil to get into the chamber. A scotch crank is better than a spring return for the ram as a spring can place undue strain on the drive, particularly if roller clutches are used.
I am of the opinion that the oil lust oozes out of the delivery hole and is drawn out by the steam flow. The only time that you would get a seperate drop is when the engine has been drifting with no steam long enough for one to form. It generally takes more than one cycle of the pump to form a drop.
I have found that about 20-25 revolutions of the driving wheels is about right for a full cycle of the pump.
It may be good idea to introduce the oil to the steam line as far as is practical from the tee junction provided that this does not require the oil line to run into the smoke box as I have seen engines with this arrangement suffer from burnt carburised oil blocking the delivery pipe. I always have the delivery fitting protrude about half way into the steam line so as not to have the oil just dribble down one side of it. This may help even out the delivery to both sides.
At times I have fitted engines with twin ram pumps when it was impossible to deliver the oil to a common steam pipe. This system works well but is inclined to deliver more oil than needed as pumps with very limited output can be less reliable and slow to prime if the tank runs dry. If a common tank is used then a divider should be included in the tank so that you can see if one pump fails.
Two of my engines have outside piston valve cylinders that could not have oil delivered to a common steam pipe. Both of these have the oil from a single ram pump delivered to a central tee and then to each cylinder. I took care to ensure that the pipes from the tee to each cylinder was of equal length and that the pump provided ample oil to ensure that each cylinder got enough. Too much oil is better than not enough. Every now and then I disconnect both of the oil pipes from the steam delivery pipes and run the engines on compressed air just to make sure that oil comes out of each delivery at the same rate. It does and they are both fit and well.
My oldest engine is now 45 years old and has done close to 2 thousand miles, and has always had the oil delivered to the cylinders via a central steam pipe and tee to each steam chest. I have never seen the valves since they were installed and about ten years ago I removed one front cylinder cover to have a look at how the bore was wearing. I was amazed at the fantastic condition that it was in and had a glaze just like that of a car engine cylinder.
I am not entirely happy with the way that the current job has the steam delivered closer to the right side cylinder than the left, but it was difficult to have it central due to its proximity to the exhaust outlet and the need to have the smoke box fittings accessable. I will ensure that the pump produces enough oil to make up for any shortfall. Anyway i'm not sure that I will physically be able to drive it on a ground level track as the backhead is so far from the rear buffer beam ,so it might just sit in the workshop and look good.
I hope that this is of interest and feel free to disagree with my comments.
Barry
Thanks for sharing your experience, it all makes perfect sense to me. I'll certainly prime everything as it goes together. I'm surprised that Viton rings seem to be better than say Nitrile ones though. Maybe it's because they're stiffer. |
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Post by mugbuilder on May 10, 2021 8:16:31 GMT
Some interesting comments about my lubricator arrangement. I have fitted mechanical lubricators to more than 40 engines over the years and will pass on as many observations as I can remember. I have found the Ewins type the most reliable if well made. It is important that the 'O'rings are a good fit in the valve body and Viton ones seem to be the best. The pump ram needs to finish its stroke just short of the clack ball as to big a gap can make the pump slow to prime as there is insufficient vacuum produced in the valve chamber on the completion of the up stroke to suck a sufficient amount of thick oil into the chamber. It is best to fill the valve chamber before fitting to the engine or it can take some time before any oil gets to the cylinders. I always make sure that the delivery pipe to the cylinders is full of oil before the final fit up. The ram must travel far enough above the top 'O' ring to allow enough time for the thick oil to get into the chamber. A scotch crank is better than a spring return for the ram as a spring can place undue strain on the drive, particularly if roller clutches are used.
I am of the opinion that the oil lust oozes out of the delivery hole and is drawn out by the steam flow. The only time that you would get a seperate drop is when the engine has been drifting with no steam long enough for one to form. It generally takes more than one cycle of the pump to form a drop.
I have found that about 20-25 revolutions of the driving wheels is about right for a full cycle of the pump.
It may be good idea to introduce the oil to the steam line as far as is practical from the tee junction provided that this does not require the oil line to run into the smoke box as I have seen engines with this arrangement suffer from burnt carburised oil blocking the delivery pipe. I always have the delivery fitting protrude about half way into the steam line so as not to have the oil just dribble down one side of it. This may help even out the delivery to both sides.
At times I have fitted engines with twin ram pumps when it was impossible to deliver the oil to a common steam pipe. This system works well but is inclined to deliver more oil than needed as pumps with very limited output can be less reliable and slow to prime if the tank runs dry. If a common tank is used then a divider should be included in the tank so that you can see if one pump fails.
Two of my engines have outside piston valve cylinders that could not have oil delivered to a common steam pipe. Both of these have the oil from a single ram pump delivered to a central tee and then to each cylinder. I took care to ensure that the pipes from the tee to each cylinder was of equal length and that the pump provided ample oil to ensure that each cylinder got enough. Too much oil is better than not enough. Every now and then I disconnect both of the oil pipes from the steam delivery pipes and run the engines on compressed air just to make sure that oil comes out of each delivery at the same rate. It does and they are both fit and well.
My oldest engine is now 45 years old and has done close to 2 thousand miles, and has always had the oil delivered to the cylinders via a central steam pipe and tee to each steam chest. I have never seen the valves since they were installed and about ten years ago I removed one front cylinder cover to have a look at how the bore was wearing. I was amazed at the fantastic condition that it was in and had a glaze just like that of a car engine cylinder.
I am not entirely happy with the way that the current job has the steam delivered closer to the right side cylinder than the left, but it was difficult to have it central due to its proximity to the exhaust outlet and the need to have the smoke box fittings accessable. I will ensure that the pump produces enough oil to make up for any shortfall. Anyway i'm not sure that I will physically be able to drive it on a ground level track as the backhead is so far from the rear buffer beam ,so it might just sit in the workshop and look good.
I hope that this is of interest and feel free to disagree with my comments.
Barry
Thanks for sharing your experience, it all makes perfect sense to me. I'll certainly prime everything as it goes together. I'm surprised that Viton rings seem to be better than say Nitrile ones though. Maybe it's because they're stiffer. I have found that nitrile rings can get hard after several years in these lubricators. |
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Post by Roger on May 10, 2021 9:56:32 GMT
Thanks for sharing your experience, it all makes perfect sense to me. I'll certainly prime everything as it goes together. I'm surprised that Viton rings seem to be better than say Nitrile ones though. Maybe it's because they're stiffer. I have found that nitrile rings can get hard after several years in these lubricators. Ok, that's good to know. |
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Post by mugbuilder on May 10, 2021 23:18:50 GMT
A large mill engine I was involved with many years ago had the oil delivered into the steam pipe via what was called an atomiser. Memory is vague, but I think it had a speen like projection into the steam main, into which the oil was pumped. The idea was that the steam, in passing 'locked' the oil off the spoon and so atomised it. I recall that it was once discovered that the spoon had worn away, and it was necessary to replace it. Has anything like this ever been tried in minature? We use a lot more oil in our small engines than full size does and is therefore no where near as critical that the supply is always equal to each side of the engine. Full size engines in Australia were strictly rationed with their consumption and i have often wondered how they got away with it . Most NSW engines had a sight feed hydrostatic lubricator mounted on top of the backhead and were regulated to deliver only a few drops of oil per minuite. This was delivered through a pipe as long as 10 to 15 feet to cylinders of up to 23 inches in diameter. Drivers were only allowed a strictly measured amount of oil calculated for the distance to be travelled, sometimes several hundred miles. In earlier times most engines just had a tallow pot somewhere on the steam chest and that must have been a bit hit and miss. I doubt that they would have been as oily inside as our models are. Cast iron cylinders become impregnated with oil over time and therefore likely to be tollerant of the occasional lack of lubricant. I always make sure that the cylinder drains are open after a run and on the way to toe steaming bay. Then after cleaning the engine close the drains and introduce a good amount of steam oil and WD40 into the cylinders or steam chests and push the engine up and down to make sure that it gets everywhere. When steamed next the drains are opened and the residue is expelled [sometimes over an onlooker] when the regulator is opened. Barry
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Post by mugbuilder on May 23, 2021 7:12:49 GMT
The cylinder drains are now hooked up and the front and rear guardn irons are fitted. For some strange reason the rear guard irons are bigger than the front ones. The chassis is now finished and time for some dummy sandboxes before the tinwork starts.   |
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Post by mugbuilder on Jun 9, 2021 0:14:57 GMT
The dummy front sandboxes are now fitted as well as the running boards. There is a lot of rivet detail on the front sections of the running boards but hardly any on the back sections as they will be covered by the side tanks and rear bunker.   |
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Post by mugbuilder on Jun 9, 2021 0:25:45 GMT
This big green thing came to town a couple of days ago. It's the 'Ausie'equivalent of the UK Flying Scotsman. Recently overhauled and on an extensive number of tours around the NSW state. It was coupled with the 'Scotsman' many years ago when they went on the 3000 Km. trip to Perth and came to Orange on the way there and back. |
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Post by mugbuilder on Jun 9, 2021 0:27:08 GMT
 Thats not a big green thing, this is. |
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Post by racinjason on Jun 9, 2021 5:54:22 GMT
We went down Monday morning to have a look and get a lot of detail photo's they have done a great job on it, we then had a ride out to spring hill a great morning.
Cheers Jason.
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Post by mugbuilder on Jun 22, 2021 4:05:01 GMT
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Post by David on Jun 24, 2021 7:36:14 GMT
So it *will* be finished by Christmas! You don't hang around.
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