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Can a IC engine be modified for steam?
Posted by: Richard E Parson (IP Logged)
Date: December 15, 2004 12:45AM
<HTML>I was thinking about using a 300 inline 6. Bore 4in. stroke of 3.9. High torque. It would seem very suitable.
I would make the cam gear 1:1 in order to get a powerstroke every 180 degrees. Double-acting right? I know plenty about condensors and car cooling systems. Will this work or is this a pipe dream?</HTML>
Steam is the future, beatch!
I would make the cam gear 1:1 in order to get a powerstroke every 180 degrees. Double-acting right? I know plenty about condensors and car cooling systems. Will this work or is this a pipe dream?</HTML>
Steam is the future, beatch!
Re: Can a IC engine be modified for steam?
Posted by: Garry Hunsaker (IP Logged)
Date: December 18, 2004 05:04PM
<HTML>Every time a new person asks if an IC engine can be converted, I think of Besler’s conversion for GM. I wonder if it will be covered in Jim Crank’s forth coming, and eagerly awaited, opus on the Dobels? For the home builder, you could do a lot worse than copying Besler’s design.
Garry</HTML>
Garry</HTML>
Re: Can a IC engine be modified for steam?
Posted by: Andy Patterson (IP Logged)
Date: December 21, 2004 05:23PM
<HTML>There would be a lot of work no mater what aproach you take. Build from scratch or convert.
The are many problems that have come up with conversions. Steam getting into the lower end making mayo out of the oil. Best to use IC engine for crank and cross head and add steam cylancers on top. You would need to do that to get DA any way. The crank through will more then likely not be right. Usually an IC engine will have two pistons on the same throw angle. Being a 4 stroke engine that gives a power stroke on every revoloution from a pair of pistons. But in a steam engine having both pistons on the same throw is unneccessary. You might try one of the more odd ball engines. Audi made a 5 cylander engine having 72 degree throw spacing. A desel engine is built for higher torque better able to handle the high torque of steam. Check the threads here and on the SACA site for conversion info. There is a great deal of experiance here.
The SACA site keeps threads much longer. So check them out.
Andy</HTML>
The are many problems that have come up with conversions. Steam getting into the lower end making mayo out of the oil. Best to use IC engine for crank and cross head and add steam cylancers on top. You would need to do that to get DA any way. The crank through will more then likely not be right. Usually an IC engine will have two pistons on the same throw angle. Being a 4 stroke engine that gives a power stroke on every revoloution from a pair of pistons. But in a steam engine having both pistons on the same throw is unneccessary. You might try one of the more odd ball engines. Audi made a 5 cylander engine having 72 degree throw spacing. A desel engine is built for higher torque better able to handle the high torque of steam. Check the threads here and on the SACA site for conversion info. There is a great deal of experiance here.
The SACA site keeps threads much longer. So check them out.
Andy</HTML>
Re: Can a IC engine be modified for steam?
Posted by: Ben in Maine (IP Logged)
Date: December 21, 2004 07:47PM
<HTML>Oh for gosh sakes,,,,,If you have a top end good for 1000rpm ,,why think of using a 3 '' stroke of a gas engine built for 3-7000 rpm ,,,The bearings at low speed with no oil pressure will be loaded over anny useful capacity,, ,,,If youre going to build a car I assume you have a adequite shop,,,ancient or otherwise,,,and can build a crank,etc,,The block is the usual stumbling block,,,Stanley Bros went from a strugglebuggy in '98 to a world record that is still rememberd 100 years later,,Can't we get something out the door that works with all the modern advancments,,and computers to boot,,,Gee, many of those shops were luckey to have gas lights,,One shop in DOWNTOWN Boston [Mc Lauthlin Elevator Co] put a 250v dc motor belted at lower speed to make 110 v ,,When the foreman came in,he threw the swich on the motor on the lineshaft,,and the lights come on Simple eh,,no switch , big motor was 600v dc , run on trolly circuit !! I saw this myself around 1980,,,Daves friend has the 6'lathe,,I passed on the 2 gear cutters,,they were on the 3rd floor on a 1way street,,{think about where to park a crane,] ,,,,I think the overwelming problem here is that people want to DESIGN and or build something without doing ANNY homework,,[[okok if you can spell it ''supppper heat'' instead of superheat,,,, i can spell it anny how ,,hohoho and get those raindeer off my roof,,Cheers Ben,,,//// P/S went up to +10f</HTML>
Re: Can a IC engine be modified for steam?
Posted by: Andy Patterson (IP Logged)
Date: December 21, 2004 09:40PM
<HTML>Hi Ben
I agree. An am doing a ground up design. But a lot of research time I am spending on it. The doer stage I never get to, maybe . Thinker type I am.
Andy</HTML>
I agree. An am doing a ground up design. But a lot of research time I am spending on it. The doer stage I never get to, maybe . Thinker type I am.
Andy</HTML>
Re: Can a IC engine be modified for steam?
Posted by: Dan Ullfig (IP Logged)
Date: December 21, 2004 10:58PM
<HTML>Andy:
You mention the angles of the crank not being right. I've been thinking of using the crankshaft off an IC to make a v4 engine. that way, with two and two cylinders offset by 90 deg, there would be a power stroke every quarter turn ( asuming SA ). I wonder, if you were going to design an engine around an existing IC 4 cyclinder, what would be the right engine? it would have to be plentiful and cheap at the local junk yard...
Dan</HTML>
You mention the angles of the crank not being right. I've been thinking of using the crankshaft off an IC to make a v4 engine. that way, with two and two cylinders offset by 90 deg, there would be a power stroke every quarter turn ( asuming SA ). I wonder, if you were going to design an engine around an existing IC 4 cyclinder, what would be the right engine? it would have to be plentiful and cheap at the local junk yard...
Dan</HTML>
Re: Can a IC engine be modified for steam?
Posted by: Ken (IP Logged)
Date: December 22, 2004 10:26AM
<HTML>Hi;
Offhand, I can't think of a plentiful automobile engine crankshaft that would be suitable, as is, for a V-4 engine. Inline 4 yes, but not a V-4. Seems to me that if you are using a typical layout, you'd be putting 2 connecting rods on each crankpin. If that was the case, the crankpins would need to be offset 180 degrees.
I can see three options for making a 4 cylinder engine using plentiful automotive cranks without modification:
Inline 4 cylinder engine with stock 4 cylinder crank
Horizontally opposed engine with stock 4 cylinder crank.
Inline 4 cylinder engine with V-8 crank.
The problem with the first two options is that both inline and flat 4 cranks have 180 degree rotations between the crankpins. As far as number of power pulses per revolution there is no advantage over a 2 cylinder engine. The Flat 4 is inherently balanced for both primary and secondary shaking forces, while the inline 4 is inherently balance for primary shaking forces.
An inline 4 using a V-8 crank would have 4 power pulses per revolution. It would be inherently balanced for secondary shaking forces but would exhibit a large rocking couple for primary shaking forces depending on rpm.
I could see using a V-8 crank as the basis for a V-4. The two center crankpins are 180 degrees apart and are wide enough to fit two connecting rods on each pin. You could conceivably saw off the front and back ends of the crank and fit drive adapters on each end. All in all, though, the work looks to be almost as great as just fabricating a crank from scratch.
All that being said, I have to wonder what sort of crankshafts the outboard industry produces. A V-4 2 stroke outboard engine would be the perfect crank donor.
Ken</HTML>
Offhand, I can't think of a plentiful automobile engine crankshaft that would be suitable, as is, for a V-4 engine. Inline 4 yes, but not a V-4. Seems to me that if you are using a typical layout, you'd be putting 2 connecting rods on each crankpin. If that was the case, the crankpins would need to be offset 180 degrees.
I can see three options for making a 4 cylinder engine using plentiful automotive cranks without modification:
Inline 4 cylinder engine with stock 4 cylinder crank
Horizontally opposed engine with stock 4 cylinder crank.
Inline 4 cylinder engine with V-8 crank.
The problem with the first two options is that both inline and flat 4 cranks have 180 degree rotations between the crankpins. As far as number of power pulses per revolution there is no advantage over a 2 cylinder engine. The Flat 4 is inherently balanced for both primary and secondary shaking forces, while the inline 4 is inherently balance for primary shaking forces.
An inline 4 using a V-8 crank would have 4 power pulses per revolution. It would be inherently balanced for secondary shaking forces but would exhibit a large rocking couple for primary shaking forces depending on rpm.
I could see using a V-8 crank as the basis for a V-4. The two center crankpins are 180 degrees apart and are wide enough to fit two connecting rods on each pin. You could conceivably saw off the front and back ends of the crank and fit drive adapters on each end. All in all, though, the work looks to be almost as great as just fabricating a crank from scratch.
All that being said, I have to wonder what sort of crankshafts the outboard industry produces. A V-4 2 stroke outboard engine would be the perfect crank donor.
Ken</HTML>
Re: Can a IC engine be modified for steam?
Posted by: Andre' Blanchard (IP Logged)
Date: December 22, 2004 10:58AM
<HTML>John Deere 2-cylinder tractors have cranks with 180 degree throws. They are long stroke, I think the 60s and 70s are in the 6 inch range, slow speed engines 900 to 1200 RPM depending on model and year.
Andre' B.</HTML>
Andre' B.</HTML>
Re: Can a IC engine be modified for steam?
Posted by: Dan Ullfig (IP Logged)
Date: December 22, 2004 04:06PM
<HTML>Ken:
Ok, what I had thought about was using an inline 4 crank, and making a v4 out of it. With the crank pins 180 from each other, and the pistons 90 deg from each other, you would have a power pulse every quarter rotation. I don't know about the balancing. The crank itself is balanced, but the pistons wouldn't be, as they are out of plane. But any v engine has that problem, right?
Dan</HTML>
Ok, what I had thought about was using an inline 4 crank, and making a v4 out of it. With the crank pins 180 from each other, and the pistons 90 deg from each other, you would have a power pulse every quarter rotation. I don't know about the balancing. The crank itself is balanced, but the pistons wouldn't be, as they are out of plane. But any v engine has that problem, right?
Dan</HTML>
Re: Can a IC engine be modified for steam?
Posted by: Andy Patterson (IP Logged)
Date: December 22, 2004 04:21PM
<HTML>Hi Dan
I plan to build my engine from scratch. Ken is the expert here when it comes to engine balance. Although he didn't talk about any European auto engines.
The John Deer crank sounds like one to look at. It would be a strong one.
Andy</HTML>
I plan to build my engine from scratch. Ken is the expert here when it comes to engine balance. Although he didn't talk about any European auto engines.
The John Deer crank sounds like one to look at. It would be a strong one.
Andy</HTML>
Re: Can a IC engine be modified for steam?
Posted by: Dan Ullfig (IP Logged)
Date: December 22, 2004 06:12PM
<HTML>Andy:
Your website mentions the possibility of using a Wankel-type engine as an expander. By what you say here, are you still considering using a piston engine after all? is the piston engine more "tried and true"?
Dan</HTML>
Your website mentions the possibility of using a Wankel-type engine as an expander. By what you say here, are you still considering using a piston engine after all? is the piston engine more "tried and true"?
Dan</HTML>
Re: Can a IC engine be modified for steam?
Posted by: George Nutz (IP Logged)
Date: December 22, 2004 07:15PM
<HTML>Dan,
Usually the crankshaft is overbalanced so that about half+ of the reciprocating forces are countered as well. There is a polar force diagram one draws for all parts considered and the smallest one can keep "the egg shape" diagram the better balanced the three dimensinal forces will be. Get your hands on a good engineering vibration book and you may see some examples of several force diagrams for different engine considerations.
George</HTML>
Usually the crankshaft is overbalanced so that about half+ of the reciprocating forces are countered as well. There is a polar force diagram one draws for all parts considered and the smallest one can keep "the egg shape" diagram the better balanced the three dimensinal forces will be. Get your hands on a good engineering vibration book and you may see some examples of several force diagrams for different engine considerations.
George</HTML>
Re: Can a IC engine be modified for steam?
Posted by: George Nutz (IP Logged)
Date: December 22, 2004 07:54PM
<HTML>Dan,
If your private message has implied to you that I am a possible spammer and need to verify myself to you than we need go no farther. If my posts appear to be spam than so be it and my 100's of posts on this forum and written papers need not go any further as I do not need to prove I am a "live, real person" to you. Good luck in your steam endeavours.
George</HTML>
If your private message has implied to you that I am a possible spammer and need to verify myself to you than we need go no farther. If my posts appear to be spam than so be it and my 100's of posts on this forum and written papers need not go any further as I do not need to prove I am a "live, real person" to you. Good luck in your steam endeavours.
George</HTML>
Re: Can a IC engine be modified for steam?
Posted by: Quentin Hilpert (IP Logged)
Date: December 22, 2004 08:44PM
<HTML>I am planning on using one of those 3 cylinder engines like in an GEO. With any luck they should have a stagard crank that will give no dead centers i.e. be able to start inself. I also plan on using the transmission simply because I will have reverse then. Westinghouse had a steam engine that was two cylinder single acting that was very high rpm. So maybe it's not such a dumb idea. I am going to use a small differential for the vavle gear using stevensen typ lobes or cams but the differential will allow me to move the cams reletive to each other that way I may not need the sliding yoke assembly on the stevensen. I am going to use a spool valve on the head and will modiy the block to the engine is a uniflow. Big plans I know but Iv'e got the engine laying around so why not. Obviously I don't think converting a gasoline engine to steam is a bad idea I may end up doing somthing different to the pistons to prevent blow by but I won't have to make the crank or the block. FYI</HTML>
Re: Can a IC engine be modified for steam?
Posted by: Ken (IP Logged)
Date: December 22, 2004 09:10PM
<HTML>Hi Dan:
Some Vee engine designs are inherently balanced for both primary and secondary shaking forces. The V-8 with 90 degree angle between cylinder banks is an inherently balanced design. Any V-12 is inherently balanced no matter what the angle because it is essentially two inline six cylinders, and an inline six is inherently balanced. This explains the traditional popularity of V-8 and I-6 designs in American cars.
I believe you are wrong about using an inline 4 to make a V-4. In a single acting engine it would have only two power pulses per revolution, and these would be 90 degrees apart with a coast time of 270 degrees. A better solution would be that taken by Smith,Petersen, Carter, Vagg and others, and simply go with a horizontally opposed 4 engine. In a SA engine that would still give you two power pulses, but at least they would be 180 degrees apart.
The general solution for shaking forces in a 2 cylinder 90 degree Vee engine with both connecting rods sharing a common pin is for the primary shaking forces to resolve out as a rotating force opposite the crankpin and for the secondary shaking forces to form a reciprocating force perpendicular to the plane bisecting the cylinders that propagates twice per revolution. When the cylinders are staggered there is a bit of a rocking couple for both primary and secondary forces, but it is fairly managable. The primary shaking force can be canceled out with an appropriate mass in the counterweight, leaving just the smaller reciprocating secondary couple.
According to my calculations, in a V-4 using two connecting rods on shared crankpins 180 degrees apart....like that tractor crank...the primary forces resolve out as perfect rotating forces. The rocking couples caused by the cylinder stagger actually cancel out in this design. The primary shaking forces on each end of the crank resolve out into pure rotating force which can be absolutely compensated for by counterweight mass. So the traditional V-4 design is perfectly balanced for the larger primary shaking force. The secondary forces resolve out as a reciprocating linear function that is described by a sine function with a periodicity of twice per revolution. Unfortunately, both secondary forces appear to be moving in unison, so the engine has a definite secondary shake. If they were moving in opposite directions, it would have a secondary rocking couple instead. This isn't really all that bad as secondary forces are smaller. With Inline 4 cylinder engines all the cylinders contribute to a vertical secondary shaking force and lots of sucessful engines have managed just fine this way.
The V-4 built on the tractor crank should also exhibit 4 evenly spaced power pulses per revolution. Any crank with a pin wide enough to support two connecting rods, with the crankpins set 180 degrees apart should suffice. This looks like a vastly better bet than constructing a V-4 on a conventional inline crank. You get more power pulses, they are evenly spaced, and the engine balance is about comparable. A V-4 built on an inline 4 crank exhibits the worst possible features.
I also did a balance analysis of a V-4 built on an inline 4 crank (I wrote a spreadsheet to analyze balance configurations, so it is pretty easy). This is one of the stranger results I have ever seen. The primary shaking forces resolve out as rotating forces, but they revolve in the opposite direction to the crank rotation! The forces are in opposite directions, so this would create a rotating rocking couple along the engine. The secondary forces look a lot more familiar with a reciprocating shaking force twice per revolution. This engine configuration will shake like the dickens. You could cancel it out with a balance shaft, although a smaller rocking couple would still remain.
Any way I look at it, using a line 4 crank to build a V-4 looks like a bad idea.
Regards,
Ken</HTML>
Some Vee engine designs are inherently balanced for both primary and secondary shaking forces. The V-8 with 90 degree angle between cylinder banks is an inherently balanced design. Any V-12 is inherently balanced no matter what the angle because it is essentially two inline six cylinders, and an inline six is inherently balanced. This explains the traditional popularity of V-8 and I-6 designs in American cars.
I believe you are wrong about using an inline 4 to make a V-4. In a single acting engine it would have only two power pulses per revolution, and these would be 90 degrees apart with a coast time of 270 degrees. A better solution would be that taken by Smith,Petersen, Carter, Vagg and others, and simply go with a horizontally opposed 4 engine. In a SA engine that would still give you two power pulses, but at least they would be 180 degrees apart.
The general solution for shaking forces in a 2 cylinder 90 degree Vee engine with both connecting rods sharing a common pin is for the primary shaking forces to resolve out as a rotating force opposite the crankpin and for the secondary shaking forces to form a reciprocating force perpendicular to the plane bisecting the cylinders that propagates twice per revolution. When the cylinders are staggered there is a bit of a rocking couple for both primary and secondary forces, but it is fairly managable. The primary shaking force can be canceled out with an appropriate mass in the counterweight, leaving just the smaller reciprocating secondary couple.
According to my calculations, in a V-4 using two connecting rods on shared crankpins 180 degrees apart....like that tractor crank...the primary forces resolve out as perfect rotating forces. The rocking couples caused by the cylinder stagger actually cancel out in this design. The primary shaking forces on each end of the crank resolve out into pure rotating force which can be absolutely compensated for by counterweight mass. So the traditional V-4 design is perfectly balanced for the larger primary shaking force. The secondary forces resolve out as a reciprocating linear function that is described by a sine function with a periodicity of twice per revolution. Unfortunately, both secondary forces appear to be moving in unison, so the engine has a definite secondary shake. If they were moving in opposite directions, it would have a secondary rocking couple instead. This isn't really all that bad as secondary forces are smaller. With Inline 4 cylinder engines all the cylinders contribute to a vertical secondary shaking force and lots of sucessful engines have managed just fine this way.
The V-4 built on the tractor crank should also exhibit 4 evenly spaced power pulses per revolution. Any crank with a pin wide enough to support two connecting rods, with the crankpins set 180 degrees apart should suffice. This looks like a vastly better bet than constructing a V-4 on a conventional inline crank. You get more power pulses, they are evenly spaced, and the engine balance is about comparable. A V-4 built on an inline 4 crank exhibits the worst possible features.
I also did a balance analysis of a V-4 built on an inline 4 crank (I wrote a spreadsheet to analyze balance configurations, so it is pretty easy). This is one of the stranger results I have ever seen. The primary shaking forces resolve out as rotating forces, but they revolve in the opposite direction to the crank rotation! The forces are in opposite directions, so this would create a rotating rocking couple along the engine. The secondary forces look a lot more familiar with a reciprocating shaking force twice per revolution. This engine configuration will shake like the dickens. You could cancel it out with a balance shaft, although a smaller rocking couple would still remain.
Any way I look at it, using a line 4 crank to build a V-4 looks like a bad idea.
Regards,
Ken</HTML>
Re: Can a IC engine be modified for steam?
Posted by: Dan Ullfig (IP Logged)
Date: December 22, 2004 09:13PM
<HTML>Hi everyone:
I just was made aware of something. When I posted to this thread, I checked the box that says "email replies to this thread to the address above". Turns out that I have a spam blocker, and now everytime anyone posts to this thread, you are going to get a letter automatically from my spam service :(. Sorry, I didn't realize this was going to happen, I appoligize, and please disregard the automatic emails you get from me challenging you to prove you're a "real, live person".</HTML>
I just was made aware of something. When I posted to this thread, I checked the box that says "email replies to this thread to the address above". Turns out that I have a spam blocker, and now everytime anyone posts to this thread, you are going to get a letter automatically from my spam service :(. Sorry, I didn't realize this was going to happen, I appoligize, and please disregard the automatic emails you get from me challenging you to prove you're a "real, live person".</HTML>
Re: Can a IC engine be modified for steam?
Posted by: Dan Ullfig (IP Logged)
Date: December 22, 2004 10:28PM
<HTML>Ken:
I didn't understand what you said about the v4 engine having only 2 pulses per revolution, with 270 deg coast.
The way I figure, the inline 4 crank has two and two pins 180 deg. apart. If you take cylinder 2 and 4, and rotate them 90 deg., then when cyl 1 is up, cyl 2 is halfway down, cyl 3 is down, cyl 4 is halfway up. That would get you 4 pulses, 90 deg. apart, right?
Dan</HTML>
I didn't understand what you said about the v4 engine having only 2 pulses per revolution, with 270 deg coast.
The way I figure, the inline 4 crank has two and two pins 180 deg. apart. If you take cylinder 2 and 4, and rotate them 90 deg., then when cyl 1 is up, cyl 2 is halfway down, cyl 3 is down, cyl 4 is halfway up. That would get you 4 pulses, 90 deg. apart, right?
Dan</HTML>
Re: Can a IC engine be modified for steam?
Posted by: Ken (IP Logged)
Date: December 22, 2004 11:21PM
<HTML>Dan:
You're right about the power pulses, I knocked my response out pretty quickly because I needed to do some last minute Christmas shopping and I apparently screwed up the quick sketch I used for my setup.
I double checked the balance calculations, and they are still correct as to thier nature. There is some partial cancellation of shaking forces in your engine. It's going to have a significant shake, but if your rpms aren't that high they should be manageable without additional cancellation. If the primary shaking force wasn't spinning in the opposite direction it actually be a rather good balance solution. Given my drathers, I'd go with a 4 cylinder crank out of a horizontally opposed engine rather than an inline 4. VW or Subaru spring to mind. This would make the engine significantly shorter and more compact. It would also tend to reduce shaking somewhat as there would be less leverage for the forces to work on.
Ken</HTML>
You're right about the power pulses, I knocked my response out pretty quickly because I needed to do some last minute Christmas shopping and I apparently screwed up the quick sketch I used for my setup.
I double checked the balance calculations, and they are still correct as to thier nature. There is some partial cancellation of shaking forces in your engine. It's going to have a significant shake, but if your rpms aren't that high they should be manageable without additional cancellation. If the primary shaking force wasn't spinning in the opposite direction it actually be a rather good balance solution. Given my drathers, I'd go with a 4 cylinder crank out of a horizontally opposed engine rather than an inline 4. VW or Subaru spring to mind. This would make the engine significantly shorter and more compact. It would also tend to reduce shaking somewhat as there would be less leverage for the forces to work on.
Ken</HTML>
Re: Can a IC engine be modified for steam?
Posted by: Dan Ullfig (IP Logged)
Date: December 22, 2004 11:36PM
<HTML>Ken:
What's this spreadsheet you talk about? is it available ( in other words, can I have it :)
Dan</HTML>
What's this spreadsheet you talk about? is it available ( in other words, can I have it :)
Dan</HTML>
Re: Can a IC engine be modified for steam?
Posted by: Dan Ullfig (IP Logged)
Date: December 22, 2004 11:47PM
<HTML>Ken:
Ok, I read up a little more on crankshafts, and now I see what you're saying. An inline 4 crank doesn't have the counterweights that v engine cranks have. So there is no mass to conteract the back and forth motion of the piston. But I just looked on ebay, and it turns out you can buy VW crankshafts with counterweights. They're meant for racing, I suppose, as they say you can rev up to 5000rpm without vibration. So I guess this would be the crank to go with? Would this crank allow me to build a v4 that doesn't shake itself to death?
Dan</HTML>
Ok, I read up a little more on crankshafts, and now I see what you're saying. An inline 4 crank doesn't have the counterweights that v engine cranks have. So there is no mass to conteract the back and forth motion of the piston. But I just looked on ebay, and it turns out you can buy VW crankshafts with counterweights. They're meant for racing, I suppose, as they say you can rev up to 5000rpm without vibration. So I guess this would be the crank to go with? Would this crank allow me to build a v4 that doesn't shake itself to death?
Dan</HTML>
Re: Can a IC engine be modified for steam?
Posted by: Ken (IP Logged)
Date: December 23, 2004 01:51AM
<HTML>Hi Dan:
I balance experimental and prototype crankshafts for GM Powertrain. The spreadsheet is a tool I put together to help me rapidly analyze different engine configurations. I don't think it would be real useful in its current state to most people, it gives me the data I need but you have to know how to analyze some of the printouts to determine the nature of the output forces.
Most cranks will have outboard counterweights. When you set up a crank it is a dynamic, or 'two plane' balance situation. These counterweights are usually adequate for most purposes. Inboard counterweights can be installed to help with the overall balance of the crank, but usually are more important in reducing the stress on inboard bearings. Some cranks, like split pin V-6, have virtually no inboard counterweights in an effort to move the pins as close together and make the most compact engine possible. All modern engines that I'm familiar with will have SOME counterweights on them.
Four cylinder cranks are symetrically laid out, so they are readily balanced. Technically they do not NEED counterweights to achieve balance because the engine geometry causes inertia unbalance forces to cancel out, but they usually have them in order to provide a place to remove weight to facilitate the actual balancing process and to reduce bending stresses along the length of the crank. Non-symetrical cranks such as V-6 and 8s require the use of 'ring weights' in the balancing process, said weights generally being equal to the rotating mass plus one half the reciprocating. More advanced practioners will take into account such variables as the weight difference between oil and metal in the lubricating passages and conn rod offset.
I'm not sure if I clicked the proper box to have my e-mail posted. If you have any specific questions you can reach me at;
kenatgm@aol.com
Regards,
Ken</HTML>
I balance experimental and prototype crankshafts for GM Powertrain. The spreadsheet is a tool I put together to help me rapidly analyze different engine configurations. I don't think it would be real useful in its current state to most people, it gives me the data I need but you have to know how to analyze some of the printouts to determine the nature of the output forces.
Most cranks will have outboard counterweights. When you set up a crank it is a dynamic, or 'two plane' balance situation. These counterweights are usually adequate for most purposes. Inboard counterweights can be installed to help with the overall balance of the crank, but usually are more important in reducing the stress on inboard bearings. Some cranks, like split pin V-6, have virtually no inboard counterweights in an effort to move the pins as close together and make the most compact engine possible. All modern engines that I'm familiar with will have SOME counterweights on them.
Four cylinder cranks are symetrically laid out, so they are readily balanced. Technically they do not NEED counterweights to achieve balance because the engine geometry causes inertia unbalance forces to cancel out, but they usually have them in order to provide a place to remove weight to facilitate the actual balancing process and to reduce bending stresses along the length of the crank. Non-symetrical cranks such as V-6 and 8s require the use of 'ring weights' in the balancing process, said weights generally being equal to the rotating mass plus one half the reciprocating. More advanced practioners will take into account such variables as the weight difference between oil and metal in the lubricating passages and conn rod offset.
I'm not sure if I clicked the proper box to have my e-mail posted. If you have any specific questions you can reach me at;
kenatgm@aol.com
Regards,
Ken</HTML>
Re: Can a IC engine be modified for steam?
Posted by: George Nutz (IP Logged)
Date: December 23, 2004 11:41AM
<HTML>Dan and Ken
As Coburn mentioned previoously the big drawback to using IC cranks as a basis is that one must be very careful to not apply a high steam pressure at very low RPM's as it wipes out the pressurised fluid fim bearings. The Paxton Pheonix three cylinder steeple compound designed specifically for steam could not have full pressure applied until a certain RPM was reached(according to Dooley). The best of the California buses-the great retro fit effort by William Brobeck- used a heavy duty diesel bottom end and solved the static bearing problem by utilizing the automatic transmission, it was much better than the Lear or SPS buses. I believe the SES engine used a diesel block/crank but was only run on the dyno where high pressure/very low RPM conditions could be carefully avoided during testing.
As far as balancing remember the reciprocation masses of a double acting steam engine are much heavier than a modern gas engine and more counterweight is needed to smooth out that ??? diagram, Ken what is the name of that polar force diagram---my old mind just can't remember.
Best of holidays to all, especially JW, George</HTML>
As Coburn mentioned previoously the big drawback to using IC cranks as a basis is that one must be very careful to not apply a high steam pressure at very low RPM's as it wipes out the pressurised fluid fim bearings. The Paxton Pheonix three cylinder steeple compound designed specifically for steam could not have full pressure applied until a certain RPM was reached(according to Dooley). The best of the California buses-the great retro fit effort by William Brobeck- used a heavy duty diesel bottom end and solved the static bearing problem by utilizing the automatic transmission, it was much better than the Lear or SPS buses. I believe the SES engine used a diesel block/crank but was only run on the dyno where high pressure/very low RPM conditions could be carefully avoided during testing.
As far as balancing remember the reciprocation masses of a double acting steam engine are much heavier than a modern gas engine and more counterweight is needed to smooth out that ??? diagram, Ken what is the name of that polar force diagram---my old mind just can't remember.
Best of holidays to all, especially JW, George</HTML>
Re: Can a IC engine be modified for steam?
Posted by: Ken (IP Logged)
Date: December 23, 2004 01:05PM
<HTML>Hi George:
I agree with you fully about automotive cranks. I prefer the tractor crank that was previously mentioned, as a low rpm engine it likely has bearing surfaces that can handle high pressure, low rpm situations. The engine I am designing right now has a built up crank and I plan to run needle/roller bearings..careful catalog searches indicate a number of products that should take peak pressures and speed with acceptable life expectancy. This should make the engine much less susceptible to failure due to momentary disruptions of oil film.
You are also right that double acting steam engines are going to have greater reciprocating weight. We can figure that the cross head and piston rod are each going to weigh at least what a piston does, so that would be at least triple the inertia forces that a single acting engine experiences. On the other hand, the inertia forces go up with the square of rpm. If you hold rpm down to about half that for which the engine is designed it should roughly be a wash.
From a balance perspective, larger counterweights may or may not be necessary in a DA engine. The engine geometry has a lot of effect on balance solutions, one could balance an inline 4 or 6 engine without any counterweights whatsoever. A V-8 absolutely needs counterweights because the forces resolve out as rotating vectors. No matter what the engine and crank design is, the crankshaft in any engine will still need to be balanced by a technician using the appropriate equipment if true balance is desired.
For a DA engine, I would LIKE to see larger inboard counterweights than are common on internal combustion engines. The higher pressures make heavier pins and main bearings look good too. All that extra reciprocating mass is going to put more bending stress on the crank and it would be nice to compensate it out. I imagine the Williams engines had some shaking problems at full throttle from what I know of their crank layout, apparent reciprocating mass and operating speed, I'm not sure they put enough hours on to see what effect that had on life expectancy.
I'm not sure about the name of the polar force plot that you refer to. From what I've seen of various reference materials, some of the terminology and practices have changed as the technology has evolved. I usually refer to graphical solutions as vector force diagrams. Computers have made balancing on the shop floor much easier. When I started the only way to figure out how much to drill was to refer to tables and eyeball, and then progressively drill to approach proper balance. Now I just let a pc talk to the balancer and a spreadsheet automatically calculates the drilling solutions almost instantly.
Regards,
Ken</HTML>
I agree with you fully about automotive cranks. I prefer the tractor crank that was previously mentioned, as a low rpm engine it likely has bearing surfaces that can handle high pressure, low rpm situations. The engine I am designing right now has a built up crank and I plan to run needle/roller bearings..careful catalog searches indicate a number of products that should take peak pressures and speed with acceptable life expectancy. This should make the engine much less susceptible to failure due to momentary disruptions of oil film.
You are also right that double acting steam engines are going to have greater reciprocating weight. We can figure that the cross head and piston rod are each going to weigh at least what a piston does, so that would be at least triple the inertia forces that a single acting engine experiences. On the other hand, the inertia forces go up with the square of rpm. If you hold rpm down to about half that for which the engine is designed it should roughly be a wash.
From a balance perspective, larger counterweights may or may not be necessary in a DA engine. The engine geometry has a lot of effect on balance solutions, one could balance an inline 4 or 6 engine without any counterweights whatsoever. A V-8 absolutely needs counterweights because the forces resolve out as rotating vectors. No matter what the engine and crank design is, the crankshaft in any engine will still need to be balanced by a technician using the appropriate equipment if true balance is desired.
For a DA engine, I would LIKE to see larger inboard counterweights than are common on internal combustion engines. The higher pressures make heavier pins and main bearings look good too. All that extra reciprocating mass is going to put more bending stress on the crank and it would be nice to compensate it out. I imagine the Williams engines had some shaking problems at full throttle from what I know of their crank layout, apparent reciprocating mass and operating speed, I'm not sure they put enough hours on to see what effect that had on life expectancy.
I'm not sure about the name of the polar force plot that you refer to. From what I've seen of various reference materials, some of the terminology and practices have changed as the technology has evolved. I usually refer to graphical solutions as vector force diagrams. Computers have made balancing on the shop floor much easier. When I started the only way to figure out how much to drill was to refer to tables and eyeball, and then progressively drill to approach proper balance. Now I just let a pc talk to the balancer and a spreadsheet automatically calculates the drilling solutions almost instantly.
Regards,
Ken</HTML>
Re: Can a IC engine be modified for steam?
Posted by: Rolly (IP Logged)
Date: December 23, 2004 02:21PM
<HTML>I have used built up cranks on most of my engines. On my small compound in my first boat the main bearing are ball and the rod bearing are rollers, not needle. Been close to thirty years now for the engine with thousands of hours of use.
I still balance my engines the old way. Weigh the piston, rod, complete with wrist pin and crosshead, rings ect. Then take some strip lead of the same weight and wrap it around the rod journal. Now you balance the crank by adding weight to the counter weights.
Off course I don’t run my engines more the 1000 rpm’s.
[ourworld.cs.com]
Rolly</HTML>
I still balance my engines the old way. Weigh the piston, rod, complete with wrist pin and crosshead, rings ect. Then take some strip lead of the same weight and wrap it around the rod journal. Now you balance the crank by adding weight to the counter weights.
Off course I don’t run my engines more the 1000 rpm’s.
[ourworld.cs.com]
Rolly</HTML>
Re: Can a IC engine be modified for steam?
Posted by: George Nutz (IP Logged)
Date: December 23, 2004 03:21PM
<HTML>Ken,
A built up crank is great--I have built up a 3 cylinder 2" X 2.5" inline with six webs and four mains that is laying around unfinished for years. Theoretically it should be balanced well enough so running 250psi @ 1800 rpm the combined unbalance forces would be less than the weight of the engine that was estimated to be 80# all up. Using 4130 or 4140 for the six webs(counterweighted according to that elusive named polar diagram) one can use very high press fits to prevent slippage---most pressed up snowmobile and other engines slip quite easily as they have low torque capacity and shouldn't be used for steam. An old SAAB 2 cycle crank is a high grade piece of work and the press fits I am told were 40-60 tons!! The use of large needle rollers is perfectly acceptable and Torringtons are very cheap, one of the problems is space requirements for a small high speed engine is that larger roller or ball bearings take up too much room on the crank pins and crosshead bearings. Some disagree with the use of needle rollers but after talking to engineers at Torrington on the applications they approved.
Using two torrington bearings side by side in the wrist pin area allows for more allowable misalighnment that one longer bearing. When one gets down to it the most pressure one can run on an engine is the weakest link so comprimises on individual parts and bearings need be adjusted for the same factor of safety. You are very fortunate to have such modern methds available.
George</HTML>
A built up crank is great--I have built up a 3 cylinder 2" X 2.5" inline with six webs and four mains that is laying around unfinished for years. Theoretically it should be balanced well enough so running 250psi @ 1800 rpm the combined unbalance forces would be less than the weight of the engine that was estimated to be 80# all up. Using 4130 or 4140 for the six webs(counterweighted according to that elusive named polar diagram) one can use very high press fits to prevent slippage---most pressed up snowmobile and other engines slip quite easily as they have low torque capacity and shouldn't be used for steam. An old SAAB 2 cycle crank is a high grade piece of work and the press fits I am told were 40-60 tons!! The use of large needle rollers is perfectly acceptable and Torringtons are very cheap, one of the problems is space requirements for a small high speed engine is that larger roller or ball bearings take up too much room on the crank pins and crosshead bearings. Some disagree with the use of needle rollers but after talking to engineers at Torrington on the applications they approved.
Using two torrington bearings side by side in the wrist pin area allows for more allowable misalighnment that one longer bearing. When one gets down to it the most pressure one can run on an engine is the weakest link so comprimises on individual parts and bearings need be adjusted for the same factor of safety. You are very fortunate to have such modern methds available.
George</HTML>
Re: Can a IC engine be modified for steam?
Posted by: Dan Ullfig (IP Logged)
Date: December 23, 2004 06:37PM
<HTML>Hey, all:
There is a company calles Scat Cranks, that make custom forged cranks. I guess it's for the racing industry. At any rate, has anyone ever priced one, and how much would you expect to pay for a custom made crank? What are the chances of getting it wrong and needing a second crank? (or God forbid, a third )
Dan</HTML>
There is a company calles Scat Cranks, that make custom forged cranks. I guess it's for the racing industry. At any rate, has anyone ever priced one, and how much would you expect to pay for a custom made crank? What are the chances of getting it wrong and needing a second crank? (or God forbid, a third )
Dan</HTML>
Re: Can a IC engine be modified for steam?
Posted by: Dan Ullfig (IP Logged)
Date: December 23, 2004 09:07PM
<HTML>George:
I'm very interested in your use of needle bearings, as I'm thinking of using them myself. Are you running the needle bearings directly on the journals, or are you using some kind of split liner? if you are not using inner races, did you have to case harden the crankshaft before grinding the journals?
I've seen needle bearings running directly on a shaft, but the shaft had to be hardened.
Dan</HTML>
I'm very interested in your use of needle bearings, as I'm thinking of using them myself. Are you running the needle bearings directly on the journals, or are you using some kind of split liner? if you are not using inner races, did you have to case harden the crankshaft before grinding the journals?
I've seen needle bearings running directly on a shaft, but the shaft had to be hardened.
Dan</HTML>
Re: Can a IC engine be modified for steam?
Posted by: Garry Hunsaker (IP Logged)
Date: December 26, 2004 03:35PM
<HTML>Dan
It's been nearly twenty years since I worked profesionally on the VW. In that time, things do change. From long ago though, Scat had the reputation of building parts that failed rather often. And, most of those failures were their cranks.
The recognised leader in old air cooled VW tech was Gene Berg Interprizes.
I just checked, and the are still in bussiness.
[www.geneberg.com]
What sold me on Berg were his tech tips that matched up with the same things I had found from ten years of tinkering on the air cooled beasts.
Ken, have you taken a look at what happens in a four cylinder boxer layout, when you rotate the front two throws ninety degrees to the rear pair? You at least get a self starting engine.
On automotive plain bearing cranks, in direct geared steamers, I suspect this would be a good place for a donkey engine running the main engine oil pump.
Garry</HTML>
It's been nearly twenty years since I worked profesionally on the VW. In that time, things do change. From long ago though, Scat had the reputation of building parts that failed rather often. And, most of those failures were their cranks.
The recognised leader in old air cooled VW tech was Gene Berg Interprizes.
I just checked, and the are still in bussiness.
[www.geneberg.com]
What sold me on Berg were his tech tips that matched up with the same things I had found from ten years of tinkering on the air cooled beasts.
Ken, have you taken a look at what happens in a four cylinder boxer layout, when you rotate the front two throws ninety degrees to the rear pair? You at least get a self starting engine.
On automotive plain bearing cranks, in direct geared steamers, I suspect this would be a good place for a donkey engine running the main engine oil pump.
Garry</HTML>
Re: Can a IC engine be modified for steam?
Posted by: Ken (IP Logged)
Date: December 26, 2004 11:21PM
<HTML>Hi Gary:
It would seem to me that rotating the front two throws 90 degrees to the rear pair wouldn't give you a self starting engine. In a VW type engine the first and fourth throws would go one direction and the two middle ones run the opposite way. Of course, the cylinders also alternate orientation as you go down the line. If crank pin #1 was at '0' and #2 was at '180', then both would be at TDC since cylinder 1 is at '0' and cylinder 2 is at '180'. The same thing would happen with the back two pair of crankpins.
For a 4 cylinder boxter engine, any adjacent pair of pins will put the adjacent pistons at TDC or BDC if the crankpins are oriented 180 to each other because the adjacent cylinders also have a 180 orientation.
To make the power pulses come out at 90 degree intervals, it would seem necessary to have 2 crankpins going in one direction (each pin serving a cylinder on opposite sides of the crankshaft) and to have 2 other crankpins also going in one direction, but 90 degrees opposite to the plane of the first two pins. I can see this working if the first two pins were both aligned to '0' degrees and the second two were both aligned to '90' degrees. Likewise, I can see it working if pins #1 and #4 were both aligned in one direction and pins #2 and #3 are both perpendicular to the other two.
In the case of the engine with the #1 and #4 pins aligned together, with #2 and #3 perpendicular, the engine exhibits a severe primary shaking force and a severe secondary rocking couple.
In the case of the engine with #1 and #2 pins aligned together, with #3 and #4 perpendicular, the engine exhibits a combined primary shake and rocking couple. Since the front two crankpins are perpendicular to the rear two, the forces on each end are not in phase. Therefore the rocking force on one end of the engine will usually be larger than the other end and then reverse. This leads to a rocking couple, with the excess force on one end tending to rock the engine as well. The secondary forces are fully compensated, they all cancel out.
The second case would actually be the preferable case, the peak shaking forces are smaller. It would also be possible to fit a balance shaft to the engine and reduce the primary forces significantly, or add two shafts and fully cancel them out.
Regards,
Ken</HTML>
It would seem to me that rotating the front two throws 90 degrees to the rear pair wouldn't give you a self starting engine. In a VW type engine the first and fourth throws would go one direction and the two middle ones run the opposite way. Of course, the cylinders also alternate orientation as you go down the line. If crank pin #1 was at '0' and #2 was at '180', then both would be at TDC since cylinder 1 is at '0' and cylinder 2 is at '180'. The same thing would happen with the back two pair of crankpins.
For a 4 cylinder boxter engine, any adjacent pair of pins will put the adjacent pistons at TDC or BDC if the crankpins are oriented 180 to each other because the adjacent cylinders also have a 180 orientation.
To make the power pulses come out at 90 degree intervals, it would seem necessary to have 2 crankpins going in one direction (each pin serving a cylinder on opposite sides of the crankshaft) and to have 2 other crankpins also going in one direction, but 90 degrees opposite to the plane of the first two pins. I can see this working if the first two pins were both aligned to '0' degrees and the second two were both aligned to '90' degrees. Likewise, I can see it working if pins #1 and #4 were both aligned in one direction and pins #2 and #3 are both perpendicular to the other two.
In the case of the engine with the #1 and #4 pins aligned together, with #2 and #3 perpendicular, the engine exhibits a severe primary shaking force and a severe secondary rocking couple.
In the case of the engine with #1 and #2 pins aligned together, with #3 and #4 perpendicular, the engine exhibits a combined primary shake and rocking couple. Since the front two crankpins are perpendicular to the rear two, the forces on each end are not in phase. Therefore the rocking force on one end of the engine will usually be larger than the other end and then reverse. This leads to a rocking couple, with the excess force on one end tending to rock the engine as well. The secondary forces are fully compensated, they all cancel out.
The second case would actually be the preferable case, the peak shaking forces are smaller. It would also be possible to fit a balance shaft to the engine and reduce the primary forces significantly, or add two shafts and fully cancel them out.
Regards,
Ken</HTML>
Re: Can a IC engine be modified for steam?
Posted by: Dan Ullfig (IP Logged)
Date: December 27, 2004 03:33AM
<HTML>Ken:
How exactly would the crank have to be designed for a v4 engine? would it be radically different from a straight 4 configuration, or would it be possible to add counterweights in such a way to make it work?
By the way, what I have in mind is a low rpm engine, tentatively not lubricated (graphite pistons, or something like that) single acting to do away with glands. Now, some leakage is expected, and I want no oil in the crankcase, so I was thinking roller bearings, grease lubrication. How did they get the roller bearings on the journals in Doble engines?
Dan</HTML>
How exactly would the crank have to be designed for a v4 engine? would it be radically different from a straight 4 configuration, or would it be possible to add counterweights in such a way to make it work?
By the way, what I have in mind is a low rpm engine, tentatively not lubricated (graphite pistons, or something like that) single acting to do away with glands. Now, some leakage is expected, and I want no oil in the crankcase, so I was thinking roller bearings, grease lubrication. How did they get the roller bearings on the journals in Doble engines?
Dan</HTML>
Re: Can a IC engine be modified for steam?
Posted by: Andy Patterson (IP Logged)
Date: December 27, 2004 05:33PM
<HTML>Hi Dan
The problem with the Wankel is the cost of development and high cost meterials to keep heat transfer within reasionable limits. In the Wankel the crank mechanism can not be seperated from the expander like in a piston engine. That creats a lot of heat problems. The main advantage of the Wankel is it"s compactness. More displacement for a goven over all engine volume.
Andy</HTML>
The problem with the Wankel is the cost of development and high cost meterials to keep heat transfer within reasionable limits. In the Wankel the crank mechanism can not be seperated from the expander like in a piston engine. That creats a lot of heat problems. The main advantage of the Wankel is it"s compactness. More displacement for a goven over all engine volume.
Andy</HTML>
Re: Can a IC engine be modified for steam?
Posted by: Ken (IP Logged)
Date: December 27, 2004 09:27PM
<HTML>Dan:
Either an inline 4 or a horizontally opposed 4 crank probably won't balance if you try to turn them into a V-4, the counterweights are going to be in the wrong place.
Beyond that, your question creates more questions than it does opportunities for answers. If you intend to go with a very low rpm engine, your horsepower is going to likely have to be well below the output of the internal combustion engine the crank is meant to service. The crank is only meant for a certain level of peak force, and IC engines usually generate their power with relatively low peak loads but higher rpm.
Also, the crankpins on many engines do not necessarily come in a standard dimension such as 75 mm or 2.5 inches, which would make fitting any off the shelf roller bearing problematical. If you ground the pins to a standard diameter, you may still not be able to get a precision polish done as the shoes that go into good polishing machines are usually designed to create a specified diameter finish. You'd need to work with the shop to accomodate their capabilities.
Furthermore, you will need to do a good study of lubricants. Greases do not necessarily support higher loads than oil lubrication. It all depends on the lubricant (for example, in the 2190 TEP oil used in navy steam turbines, the letters EP stand for 'extreme pressure') and the lubrication system. It is usually easier to wipe a bearing at low rpm and high load than at higher rpm...see the Langmuir theory of lubrication.
I'm not an expert, I believe Doble split the big ends of the connecting rods and inserted steel rollers that circulated freely, to the best of my knowledge he didn't use caged bearings.
Past a certain point you have to do some engineering, crunch some numbers, find available components, figure out what you need to fabricate and make sure that everything is up to snuff. For my money, if I were building a V-4, I'd go with a built-up two throw crank or check around for 2 throw 2 stroke cranks to see if anything is suitable.
Regards,
Ken</HTML>
Either an inline 4 or a horizontally opposed 4 crank probably won't balance if you try to turn them into a V-4, the counterweights are going to be in the wrong place.
Beyond that, your question creates more questions than it does opportunities for answers. If you intend to go with a very low rpm engine, your horsepower is going to likely have to be well below the output of the internal combustion engine the crank is meant to service. The crank is only meant for a certain level of peak force, and IC engines usually generate their power with relatively low peak loads but higher rpm.
Also, the crankpins on many engines do not necessarily come in a standard dimension such as 75 mm or 2.5 inches, which would make fitting any off the shelf roller bearing problematical. If you ground the pins to a standard diameter, you may still not be able to get a precision polish done as the shoes that go into good polishing machines are usually designed to create a specified diameter finish. You'd need to work with the shop to accomodate their capabilities.
Furthermore, you will need to do a good study of lubricants. Greases do not necessarily support higher loads than oil lubrication. It all depends on the lubricant (for example, in the 2190 TEP oil used in navy steam turbines, the letters EP stand for 'extreme pressure') and the lubrication system. It is usually easier to wipe a bearing at low rpm and high load than at higher rpm...see the Langmuir theory of lubrication.
I'm not an expert, I believe Doble split the big ends of the connecting rods and inserted steel rollers that circulated freely, to the best of my knowledge he didn't use caged bearings.
Past a certain point you have to do some engineering, crunch some numbers, find available components, figure out what you need to fabricate and make sure that everything is up to snuff. For my money, if I were building a V-4, I'd go with a built-up two throw crank or check around for 2 throw 2 stroke cranks to see if anything is suitable.
Regards,
Ken</HTML>
Re: Can a IC engine be modified for steam?
Posted by: Garry Hunsaker (IP Logged)
Date: December 28, 2004 12:43AM
<HTML>Ken & Dan
Yep, Ken, I got DA engines on the brain. With a single acting engine you might get a fifty fifty chance of the engine starting on its own. A DA boxer might be self starting, but what applying torque to both opposing throws at the same time would do... Hmmm?
On a V4 with 90 degree banks, George Nutz mentioned something a while back. I had to set down and sketch it out to understand what he stated. To get even power impulses from a DA V4, it looks like you need two throws at 135 degrees to one another. That’s assuming you put two rods on each throw. Unless someone knows of a crank that has two throws already in this relationship, it looks like a good time to start looking at built up cranks.
Just a pondering...
Garry</HTML>
Yep, Ken, I got DA engines on the brain. With a single acting engine you might get a fifty fifty chance of the engine starting on its own. A DA boxer might be self starting, but what applying torque to both opposing throws at the same time would do... Hmmm?
On a V4 with 90 degree banks, George Nutz mentioned something a while back. I had to set down and sketch it out to understand what he stated. To get even power impulses from a DA V4, it looks like you need two throws at 135 degrees to one another. That’s assuming you put two rods on each throw. Unless someone knows of a crank that has two throws already in this relationship, it looks like a good time to start looking at built up cranks.
Just a pondering...
Garry</HTML>
Re:why bother w/IC engine
Posted by: Ben in Maine (IP Logged)
Date: December 28, 2004 11:32AM
<HTML>Hi,,What am I missing this time,,,A 2 cyl DA,,{double acting ] will have a power impulse starting every 90 deg' . Therefore a 4 cyl will have a power impulse starting every45 deg,,A crank and cyl' layout,,that is,,V or in line should be able to accomodate this. Gas engines sometimes use other angles on V engines,,the old Lincoln was a 60 deg' ,,not 90,,etc. We are concerned w/starting so impulses should be even,,or at least overlaping in long cutoff. Seeing as we dont seem to have solved the hi speed problem,,I vote for the DA layout. Lumpy torque in the Stanley is a NON issue,,ask anyone who has ridden in one,,even w/ poorly timed valves...Cheers Ben</HTML>
Re:why bother w/IC engine
Posted by: Garry Hunsaker (IP Logged)
Date: December 28, 2004 02:49PM
<HTML>I don't think your missing anything Ben. Myself, I am faulting my current lack of logic to a lack of sun light induced seasonal disorder. Perhaps, it's time to hibernate for awhile. :)
A single acting four cylinder boxer, with the front pair of throws set 90 degrees to the rear pair, should have the same power impulses as the Stanley. With proper valve timing, it’s self starting capabilities should be the same. It even should be possible to do a considerably better job balancing the engine. The one thing I like about the boxer is, it possible to design a very strong crankcase and still keep the weight down. Personally myself, I am not a big fan of SA steamers. Unless, someone comes up with rings that allow ‘no’ water into the crankcase.
And oh yes, a Stanley is a ride that has to be experienced! I have only had the one trip years ago, but it is not something one forgets. Now if I could just forget the owner telling me it had the original copper boiler, after Jim Crank pointed out the possible outcome of using such antiques.
Cheers to you Ben
Garry</HTML>
A single acting four cylinder boxer, with the front pair of throws set 90 degrees to the rear pair, should have the same power impulses as the Stanley. With proper valve timing, it’s self starting capabilities should be the same. It even should be possible to do a considerably better job balancing the engine. The one thing I like about the boxer is, it possible to design a very strong crankcase and still keep the weight down. Personally myself, I am not a big fan of SA steamers. Unless, someone comes up with rings that allow ‘no’ water into the crankcase.
And oh yes, a Stanley is a ride that has to be experienced! I have only had the one trip years ago, but it is not something one forgets. Now if I could just forget the owner telling me it had the original copper boiler, after Jim Crank pointed out the possible outcome of using such antiques.
Cheers to you Ben
Garry</HTML>
Re:why bother w/IC engine
Posted by: Ken (IP Logged)
Date: December 28, 2004 06:14PM
<HTML>Hi Gary:
I agree. A single acting horizontally opposed 4 cylinder with the front two throws perpendicular to the back two throws will be just as self starting as a Stanley given identical cutoffs. I'd probably want to simplify things further and make it a two pin crank, with both pins set 90 degrees apart and the front and rear pairs of connecting rods each sharing a pin just as in a V-8.
This layout will be smoother than a Stanley at high speed, since the secondary forces are fully cancelled and because overall reciprocating weight should be lower. A single balance shaft on either engine would make a huge difference at high speeds, with the boxter approaching full balance depending on shaft location.
I've idly wondered just what the reciprocating masses in the old Stanley land speed record machine were, and whether or not Stanley roughly balanced the engine to the formula where ring weights = rotating mass + 1/2 reciprocating mass. Considering the crank is mounted far astern, the masses seem pretty high, the engine layout doesn't do much to compensate out inertia forces, and that machine was REALLY flying, it makes me wonder if unbalance forces didn't contribute to the machines loss of control.
Regards,
Ken</HTML>
I agree. A single acting horizontally opposed 4 cylinder with the front two throws perpendicular to the back two throws will be just as self starting as a Stanley given identical cutoffs. I'd probably want to simplify things further and make it a two pin crank, with both pins set 90 degrees apart and the front and rear pairs of connecting rods each sharing a pin just as in a V-8.
This layout will be smoother than a Stanley at high speed, since the secondary forces are fully cancelled and because overall reciprocating weight should be lower. A single balance shaft on either engine would make a huge difference at high speeds, with the boxter approaching full balance depending on shaft location.
I've idly wondered just what the reciprocating masses in the old Stanley land speed record machine were, and whether or not Stanley roughly balanced the engine to the formula where ring weights = rotating mass + 1/2 reciprocating mass. Considering the crank is mounted far astern, the masses seem pretty high, the engine layout doesn't do much to compensate out inertia forces, and that machine was REALLY flying, it makes me wonder if unbalance forces didn't contribute to the machines loss of control.
Regards,
Ken</HTML>
Re:why bother w/IC engine
Posted by: Ben in Maine (IP Logged)
Date: December 28, 2004 08:38PM
<HTML>Please refer to the gearing on racers,,,84/42 or there abouts,,Axle at 60 mph = 600 rpm engine 300rpm so at 120mph engine is at 600 rpm George may correct these figgures a bit,,but they are in the ballpark. 07' was geared a bit lower,, Cheers Ben</HTML>
Re:why bother w/IC engine
Posted by: Peter Brow (IP Logged)
Date: December 29, 2004 01:00AM
<HTML>Great stuff, guys!
Ken, very interesting about the Stanley crankshaft being way way aft. Hadn't thought about that, definitely makes one wonder about balancing this engine type. I don't know what to do about that, leaning toward the 1/2 recip counterweights, but my cranks are designed for easy counterweight swaps for experimentation, so I can find out what works & not, empirically.
Other "food for thought" factors in Stanley-type engines are the counterweights being inboard of the overhung big ends rather than flanking them to centerline the recip-balance forces, and the crankshaft being _extremely_ short, bragged about in late Stanley lit so maybe they were doing some balance analysis. Then there's the blasted engine frame flex, with force vectors angling off in all directions. Reminds me of the Barrett engine and some others, a bear to analyze, & flunks my personal design preferences all over the place, but the blasted things still run great.
As they said of bumblebees, standard aeronautical analysis "proves" they can't fly, yet they do. Fortunately bumblebees aren't aeronautical engineers, and fly with complete confidence. Personally I just figure that if anything runs well, all I have to say anymore is a well-earned "attaboy". I think that there are a lot of very different ways to get good (& bad) results in steam cars, though it sure ain't easy whichever approach one chooses.
I'm really looking forward to seeing the Williams engine restoration/dyno tests which are reportedly in the works. That is going to be extremely interesting. I've heard & considered both sides on that, and don't know what to expect. As that wise old exemplar of empiricism Professor Owl said in the old Tootsie Pop commercials, "let's find out".
Peter</HTML>
Ken, very interesting about the Stanley crankshaft being way way aft. Hadn't thought about that, definitely makes one wonder about balancing this engine type. I don't know what to do about that, leaning toward the 1/2 recip counterweights, but my cranks are designed for easy counterweight swaps for experimentation, so I can find out what works & not, empirically.
Other "food for thought" factors in Stanley-type engines are the counterweights being inboard of the overhung big ends rather than flanking them to centerline the recip-balance forces, and the crankshaft being _extremely_ short, bragged about in late Stanley lit so maybe they were doing some balance analysis. Then there's the blasted engine frame flex, with force vectors angling off in all directions. Reminds me of the Barrett engine and some others, a bear to analyze, & flunks my personal design preferences all over the place, but the blasted things still run great.
As they said of bumblebees, standard aeronautical analysis "proves" they can't fly, yet they do. Fortunately bumblebees aren't aeronautical engineers, and fly with complete confidence. Personally I just figure that if anything runs well, all I have to say anymore is a well-earned "attaboy". I think that there are a lot of very different ways to get good (& bad) results in steam cars, though it sure ain't easy whichever approach one chooses.
I'm really looking forward to seeing the Williams engine restoration/dyno tests which are reportedly in the works. That is going to be extremely interesting. I've heard & considered both sides on that, and don't know what to expect. As that wise old exemplar of empiricism Professor Owl said in the old Tootsie Pop commercials, "let's find out".
Peter</HTML>
Re:why bother w/IC engine
Posted by: Garry Hunsaker (IP Logged)
Date: December 29, 2004 02:31AM
<HTML>Ken, your right again... cheese bits, I swear my brain left the building before I knew it was gone.
For the boxer layout to match the Stanley, you would have to go to a two throw crank. With the standard four throw boxer layout, with a pair of pistons moving in and out at the same time, your back to the fifty fifty chance of a self starting engine every time you stopped the beast.
I’m beginning to think I should stick with a single throw V twin, or an inline three, and quit confusing myself.
Garry</HTML>
For the boxer layout to match the Stanley, you would have to go to a two throw crank. With the standard four throw boxer layout, with a pair of pistons moving in and out at the same time, your back to the fifty fifty chance of a self starting engine every time you stopped the beast.
I’m beginning to think I should stick with a single throw V twin, or an inline three, and quit confusing myself.
Garry</HTML>
Re:why bother w/IC engine
Posted by: George Nutz (IP Logged)
Date: December 29, 2004 11:54AM
<HTML>Garry,
There are a few of us that really love the three cyl DA inline, self starting with 25+% cutoff and a very smooth torque curve. I was fiddling with the idea many years ago of a 3 cylinder 3.25 X4" (200CID) with the engine up against the firewall of my old Dodge Caravan and sitting on the ring gear of the front wheel drive differential that is bolted to the frame. It can be a very compact unit and left enough room for an 8GPH Lamont boiler in the front---all the dimensions and most of the design had been worked out a dozen years ago. The width of the car would provide a very large area for a condenser the size of two standard Dodge radiators.
All the plumbing up front and the engine not flopping up and down like a Stanley. Most importantly there was a huge storage area behind the driver for all the spare parts, torches etc. that one needs to carry around when going off in a prototype. ;o) . Long time ago---
George</HTML>
There are a few of us that really love the three cyl DA inline, self starting with 25+% cutoff and a very smooth torque curve. I was fiddling with the idea many years ago of a 3 cylinder 3.25 X4" (200CID) with the engine up against the firewall of my old Dodge Caravan and sitting on the ring gear of the front wheel drive differential that is bolted to the frame. It can be a very compact unit and left enough room for an 8GPH Lamont boiler in the front---all the dimensions and most of the design had been worked out a dozen years ago. The width of the car would provide a very large area for a condenser the size of two standard Dodge radiators.
All the plumbing up front and the engine not flopping up and down like a Stanley. Most importantly there was a huge storage area behind the driver for all the spare parts, torches etc. that one needs to carry around when going off in a prototype. ;o) . Long time ago---
George</HTML>
Re:why bother w/IC engine
Posted by: Rolly (IP Logged)
Date: December 29, 2004 12:25PM
<HTML>George
Are you still dreaming of this stuff as you hit golf balls down in Florida and lunch with ten old lady’s at a time.
Rolly</HTML>
Are you still dreaming of this stuff as you hit golf balls down in Florida and lunch with ten old lady’s at a time.
Rolly</HTML>
Re:why bother w/IC engine
Posted by: George Nutz (IP Logged)
Date: December 29, 2004 03:48PM
<HTML>Rolly,
Yes I can still dream--its about the only thing my mind or body still does well. And I don't even care if the ten old ladies beat my pants off at the game----just having a most wonderful time, it is as close to "heaven on earth" as I will get.
Remember, you are the one that told me that my moving to this retirement community would be my last step before purgatory!
HAPPY NEW YEAR!! George</HTML>
Yes I can still dream--its about the only thing my mind or body still does well. And I don't even care if the ten old ladies beat my pants off at the game----just having a most wonderful time, it is as close to "heaven on earth" as I will get.
Remember, you are the one that told me that my moving to this retirement community would be my last step before purgatory!
HAPPY NEW YEAR!! George</HTML>
Re:why bother w/IC engine
Posted by: Garry Hunsaker (IP Logged)
Date: December 29, 2004 08:00PM
<HTML>Well... Yah know George, there are a heck of a lot of those old doge caravans still around. Was your work with this just the basic power, size, and dimensions, of what it would take? Or, did this turn into more of the nuts and bolts bit of engineering?
Using a minvan for a prototype is a dang good idea. Lots of room for spares. The scariest thing I can think of is to build an experimental steamer and have nothing go wrong for thousands of miles. The further it went, the more I would be worried about what was going to break.
Not that I’m the paranoid type... No! not at all! :)
Glad to hear you have found heaven on Earth George. That is not an easy thing to do these days. Is it actually the ten old ladies that are making you smile, or is there a machine shop specializing in steamers the other side of the golf course you haven’t told us about yet?
Garry</HTML>
Using a minvan for a prototype is a dang good idea. Lots of room for spares. The scariest thing I can think of is to build an experimental steamer and have nothing go wrong for thousands of miles. The further it went, the more I would be worried about what was going to break.
Not that I’m the paranoid type... No! not at all! :)
Glad to hear you have found heaven on Earth George. That is not an easy thing to do these days. Is it actually the ten old ladies that are making you smile, or is there a machine shop specializing in steamers the other side of the golf course you haven’t told us about yet?
Garry</HTML>
Re:why bother w/IC engine
Posted by: Ken (IP Logged)
Date: December 29, 2004 08:49PM
<HTML>Hi Gary:
One option to consider instead of a Vee Twin or an inline 3 is a W-3, Abner Doble writes about this configuration in the Walton book. The W-3 has 3 cylinders spaced 60 degrees apart on a single common crankpin. In a double acting engine it has all the power pulses evenly spaced during each revolution, so nicely self starting.
There might be some other advantages...it would be pretty flat like a radial, but without a 'bottom' cylinder, so it would lie flat against a bellcrank housing just about as nicely as a Vee Twin. If all three cylinders have equal reciprocating mass, it is perfectly balanced for primary shaking forces, so much smoother than a Vee Twin or Inline 3. A single eccentric can drive all three valve gears, so possible reduction in part counts could be realized. The crank is readily fabricated, it is just a single pin, so no more tricky than a single cylinder engine. I can even see an overhung crank working in this configuration.
Just a thought, anyhow.
Regards,
Ken</HTML>
One option to consider instead of a Vee Twin or an inline 3 is a W-3, Abner Doble writes about this configuration in the Walton book. The W-3 has 3 cylinders spaced 60 degrees apart on a single common crankpin. In a double acting engine it has all the power pulses evenly spaced during each revolution, so nicely self starting.
There might be some other advantages...it would be pretty flat like a radial, but without a 'bottom' cylinder, so it would lie flat against a bellcrank housing just about as nicely as a Vee Twin. If all three cylinders have equal reciprocating mass, it is perfectly balanced for primary shaking forces, so much smoother than a Vee Twin or Inline 3. A single eccentric can drive all three valve gears, so possible reduction in part counts could be realized. The crank is readily fabricated, it is just a single pin, so no more tricky than a single cylinder engine. I can even see an overhung crank working in this configuration.
Just a thought, anyhow.
Regards,
Ken</HTML>
Re:why bother w/IC engine
Posted by: Mark Stacey (IP Logged)
Date: December 30, 2004 10:26PM
<HTML>Just curious is there a load / bearing area ratio for plain bearings? Once the current projects are out of the way (hysterical laughter) I'd like to base an engine on 3 cylinder short block from a small Japanese car. Can you extrapolate from steam examples that use plain beatings such as the Sentinal laydown single acting 4 cylinder truck engine, steam winches, steam trains or even the cross head cone bearing in a Stanley engine?
Cheers
Mark Stacey
www.cncprototyping.co.nz</HTML>
Cheers
Mark Stacey
www.cncprototyping.co.nz</HTML>
Re:why bother w/IC engine
Posted by: David K. Nergaard (IP Logged)
Date: January 16, 2005 12:22PM
<HTML>Mark, any engineering handbook will give the data needed for bearing design. The older editions are usually more helpful than the latest, look for the fourth edition of Mark's or the eleventh of Kent's.</HTML>
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