Ambitious newby

[brsanko]

Hello I have absolutely no exerience in machining, but I have designed an engine that I would like to build and want to know everything I need to know in order to build it. I know this sounds incredibly ambitious but I have an IQ of 140, nothing but time on my hands and a big chunck of money comming my way. If anybody would like to tell me what I need starting with books or websites to read and then what tools I should get and what materials I need, I'm all ears. Of course I will be doing as much research on my own as I can but nobody seems to put information out in the form that would benefit me most.
Thank you
Brett R. Sanko

[blackburn mark]

if i had an IQ of 141 i guess i would know what type of engine your after building... gas turbine, two stroke, four stroke, steam, wankel

designing and making a two or four stroke is no real big issue in principle, getting it to run for more than five minutes without it self destructing can be a bit rocket science

a manual mill and a lathe would see you through building a two or four stroke (belt driven cam's) and maybe a wankel if you add cnc

give us an idea as to type and use

[brsanko]

Actually it's none of those, take a look at the google sketchup 3D library, I uploaded it as the Sanko Engine, if you're interested. It is simple like a 2 stroke (no moving valves or camshafts), and it is also a diesel, so no spark plugs either. It is a boxer configuration with 4 cylinders but that doesn't tell the whole story. I'd like to make it out of aluminum. I will export some 2D drawings and post them.

Thanks for the response.

[JAZZCNC]

My Ex wife has An IQ in the 140 region but my Dog has more common sense and abilty to think out problems. She's the most intelligent dumby I know.. .:sentimental:

Mark sounds like Bretts designed the engine already but no idea how to turn it into reality.?

Brett in designing the engine you have done possibly less than 20% of the process towards a succesful engine. The hard and skillfull part starts now and no matter how intelligent if you havent got the skills to machine to high tolerences or the experience to R&D designs then your in for a long and expensive journey with high potential for disapointment.!!

My advice would be take the time to develope the engineering skills, maybe take some class's along side self development gaining hands on experience using own machines.
High IQ along with library full of books giving all Theory in the world can't compare to time served on machines.

I don't think for one minute you won't succed but I do know it will be far longer journey than you possibly realise before you have the skills to build a succeful reliable working engine.!!

Good luck.!

[brsanko]

Uhm, isn't that what I was asking for help in doing? You pretty much regurgitated what I already said with a large dose of negative attitude. I'm asking what tools I should start out with and your answer is to start out with my own tools? Does anyone have anything helpful to say? BTW Inteligence = problem solving ability. Inteligent people are often mistaken for fools because the people watching them aren't smart enough to understand their methods. Smart kids have trouble paying attention in school because school moves so slow that they aren't learning anything. Why does everyone assume that when someone asks how to do something they are expecting the answer to be easy. I have spent over 20 year perfecting this design, I wasn't expecting to learn how to build it in 6 months.

[JAZZCNC]

Nah your correct us negative dumbies know nothing.!! . . . 15yrs plus working in R&D for Honda I learnt nothing.!!

Good luck.!!

( Oh and my advice, the only advice possible given the sparse details, was seek training. With small amount of training you won't need to ask what are relatively basic questions that really any person of average intelligence could easily find out with just a simple google search.!! :positive:)

[blackburn mark]

Uhm, isn't that what I was asking for help in doing? You pretty much regurgitated what I already said with a large dose of negative attitude. I'm asking what tools I should start out with and your answer is to start out with my own tools? Does anyone have anything helpful to say? BTW Inteligence = problem solving ability. Inteligent people are often mistaken for fools because the people watching them aren't smart enough to understand their methods. Smart kids have trouble paying attention in school because school moves so slow that they aren't learning anything. Why does everyone assume that when someone asks how to do something they are expecting the answer to be easy. I have spent over 20 year perfecting this design, I wasn't expecting to learn how to build it in 6 months.

easy Brett, dont mean to be negative and youll have to excuse jazz (yorkshireman)

iv had a look at your drawing... iv no idea how your porting those double combustion chambers or getting around the conection rod issue (cant picture it)
i imagine it could be a tad complex to machine unless you design within the 2.5D machining limitations (a 4th axis might come in handy)
the supercharger/turbo you describe is a big ask (you only have to look at a turbo funny and it will self destruct lol)
two stokes are not so good with efficiency and unless you inject emissions will be poor and you will probably still get some leak through your open ports
(8x injectors would take some doing)
are you making a show piece ? proof of concept ? scale ?
get some drawing up :)

im with jazz on the idea that it will be a long long road and there is a risk of running out of gumtion if you ask to much of yourself... iv got to admire your get up n go... just hope it lasts :)

[brsanko]

Like I said I've been working on it off and on for 20 odd years. The model is 3D and disassembleable. Sorry if I got a bit short with anybody, having a rough day. I know it will be a long road and really wasn't thinking about making the turbo myself. I'll try to get the cutaway drawing posted.

[brsanko]

I know I'll need to try a lot of6206620762086209 easier projects to begin with but I'm gonna have the money here in a few months so I figured now would be a good time to get the big equipment I'm gonna need before the money's all gone. Here are a few pics let me know what you would like to see closer. I do think that direct injection would be the only way to go with this along with fully computerized control of said injection.

[Gunny]

Uhm, isn't that what I was asking for help in doing? You
pretty much regurgitated what I already said with a large dose of negative
attitude. I'm asking what tools I should start out with and your answer is to
start out with my own tools? Does anyone have anything helpful to say? BTW
Inteligence = problem solving ability. Inteligent people are often mistaken for r
fools because the people watching them aren't smart enough to understand their
methods. <br><br><br>

[Robin Hewitt]

There's something missing there, presume this is a simplified drawing. You can't run a round bar against a flat and ask it to push. You have to put a box around the bar so you have flats to do the rubbing.

[blackburn mark]

brett, its allways a good idea to let people have a look at your drawings so they can pull them to bits :) try not to take any criticism personaly... most of us have had a go at re-inventing the wheel and if nothing else, the attempt is fun and beats watching eastenders :)

your crank looks to have no meaningful counterbalance
your inner cylinder ports wont pull as much volume as your outer ports because of the con-rod obstruction (not sure if that would be a massive issue)
the crank will have a very small footprint in that slot (not sure if that will last long)

iv not seen a two stoke with injection, i think understand the issues you are trying to solve with injecting but im also assuming that the reason we dont see it is to do with the optimum injection timing being during induction so it would follow that the exaust port would still be open during injection and you would still be left with the old issue of raw fuel escaping before the exaust port closes (im sure two srokes are being phazed out for that very reason, terrible imissions)

im reasonabley sure you could machine most of those parts with a lathe & cnc mill (im not overly confident on your design at this point though)

[Swarfing]

BR i can see some issues with your design and position of TDC when firing happens. With everything being at opposing positions you will just end up with a pile of bits as it locks up upon detonation. I would look at a more traditional layout of the crankshaft myself? As for tools a Mill and a lathe is must for what you are doing. Buy the biggest you can get away with on your pocket and space. Allow plenty of time to learn the basics to save hundreds of hours screwing it up. Expect to spend more money on the consumables, hand tools and measuring devices than the machines.

The original question you asked is quite wide so list out:

1. what do you want to achieve (be completely honest)
2. what kit and tools do you already have?
3. what space do you have?
4. do you want buy or build?
5. estimate the time you want to complete your goals (then double it)

If you can come back with some of these answers people here maybe able to answer your questions. High IQ or not please ask the stupid questions or you will not get correct answers.

This hobby is very expensive so spend as much time reading where people have gone wrong before instead of looking at what looks shiny. Read lots and lots, read again and once you have done that go back and read it again.

"Children that run before they walk miss out on the detail they would have seen if they had crawled first" - My mothers words to my kids

Don't be afraid to experiment as long as you expect failure and can afford it. Failing can teach more than paying for training in some cases.

[JAZZCNC]

easy Brett, dont mean to be negative and youll have to excuse jazz (yorkshireman)

No need to make excuse's for me Mr blackburn If he can't workout the diffrence between negative attitude and Honest realistic advice then maybe he needs to take the test again.?? (Oh!!. . If he can't handle a Yorkmans to the point delivery then tuff.!!)

The most Ironic thing being that for the first 15yrs of working life (Excluding the 10-12yrs from the age 5-16 growing up has grease monkey in my uncles workshop!) my payed day job was mostly R&D engine devolpment and the last 15yrs spent honing my skills tuning and developing race engines for my other obsessive obession MotoX.!!. . . . CNC become another obsession thru the need to help aid in Engine development.!! . . So I find it rather funny he's managed to pissoff one of probably only a few people on this forum with real world experience of engine development. .:hysterical::hysterical:. . . . . Anyway Crack on and F-A-B Brains.!!

[brsanko]

5 1/2 inches, slightly below average, that's why I'm getting into engineering. I'm not trying to brag. just letting people know they don't have to baby talk to me and that I am capable of learning what I am asking about. This is the kind of discussion I was hoping to avoid. It doesn't matter how you approch these forums if you come in all humble and meek people assume you're an idiot and you won't get it anyway. If you want to coment on my tone or attitude go pester people on FB. I want to talk about machine work. If you act humble people get a big head and put you down, if you act confident people get insecure and put you down. I guess all forums are a waste of time and no matter where you go all you get is people trying to prove they are better than you. My God children grow up! I haven't put anyone down I haven't claimed to be smarter than anyone here. everything I have said has been relivant and I still get nothing but pissing contests from people I am asking for advice. If anyone is actually interested in helping me PM me. I can't put up with 40 year old 3rd graders.

[brsanko]

Jazz, you haven't said anything usefull, and if you actually had any knowledge you would have been honored to have been asked for advice. But seeing as you couldn't think of anything useful to say you insted decided to discourage me and say absoutely nothing of any value in 3 long paragraphs. I don't want your help and I would appreciate it if you would refrain from reading my posts in the future. Any knowledge you might actually have is so clouded by your ego and negativity I don't think you could teach a dog to urinate.

[rnr107]

Hi brsanko,
Before starting building angine or anything else...First thing first...
How much space have you got available as a workshop?
What is your Machines + tools budget?
his will determine what machine you can buy...

If you've got anought space, get a bridgeport... You can get one for not too much money. And these are good!

RNR

[Gunny]

5 1/2 inches, slightly below average, that's why I'm getting into engineering.

Haha :). Is this an existing member on a windup?

Read this book cover to cover, http://www.amazon.co.uk/Model-Engineering-A-Foundation-Course/dp/1854861522/ref=sr_1_1?ie=UTF8&qid=1341044128&sr=8-1 and then start by buying a lathe. The final chapter in the book covers this.

[mocha]

A combustion chamber at each end of the cylinder eh? :-)

Turbo charger direct drive on start up and clutch disengages once EGT reaches working temperature?

Scotch yolk?

Looks rather like a modified 'Bourke' engine...


Hmm... interesting.

[JAZZCNC]

Jazz, you haven't said anything usefull, and if you actually had any knowledge you would have been honored to have been asked for advice. But seeing as you couldn't think of anything useful to say you insted decided to discourage me and say absoutely nothing of any value in 3 long paragraphs. I don't want your help and I would appreciate it if you would refrain from reading my posts in the future. Any knowledge you might actually have is so clouded by your ego and negativity I don't think you could teach a dog to urinate.

Ok I'll ignore the insults for now they are wasted on me anyway I've thicker skin than that.!!

First at the time of posting given there was no information or designs on your engine my advice was relavent and practicle. High IQ alone doesn't mean you'll be a competent machinist or engineer which you'll need to be for such a project. . . Equally buying the biggest or most advanced machinery won't make up for a lack of skill.! . . .So seeking training his sound advice.!!

I could have said, like others have you need a Mill & Lathe (Personally thou a cyclindrical grinder would have been on the list.!!) but thats pritty lose advice and at the time of posting your needs unknown so didn't.

Now after seeing the design and given your clever attitude plus the insults the only advice I'm parting with is invest in CFD/1DGDS & FEA before any machinery.!! The next 10yrs redesigning should give you plenty of time to workout whats needed and gain some engineering skills.!

Has for the request for me to stop reading your posts then request Denied because I like a good laugh.!! . . . BUT I fully intend refraining from posting so you have a result there.!!

[blackburn mark]

engaging in a bit of philanthropy jazz? or are we just making sure we better than anyone else and weakness is not to be toleraited?

[Robin Hewitt]

A combustion chamber at each end of the cylinder eh? :-)

I think the inside chamber is to compress the air that will recharge the outside chamber. He can't use the crank case to do the 'blow' in the usual fashion.

I notice people making multi-cylinder steam engines using a swash plate to get the reciprocation, wonder if you could combine the two ideas... If you made the lower cylinders larger than the combustion chambers you could get a good flush.

Right now the design looks totally naff, but can't we assume it's just a short stroked, simplified drawing to explain the cycle? Even us low IQ types with large penises can see it doesn't have a lot of hope.

[blackburn mark]

i assumed expansion chambers would do all the work and "suck" the next charge in

[Tenson]

brsanko, I think the reason you are getting short attitudes is because your first post made a point of telling people how clever you are. Everyone on this forum is pretty clever and skilled, so if you want them to accept and help you, just need just show your are their equal in the quality content of your posts.

People are going to rip your design apart, and you probably don't even want that since you came here for machining advice, not engine advice. Still, if you know better about the design just ignore it and ask for what help you need.

[Robin Hewitt]

i assumed expansion chambers would do all the work and "suck" the next charge in

Did you miss the 2 stroke part? There is no suck unless you do something really clever with the exhaust pipe geometry.

To pep up a 2 stroke you put a clack valve between the carburettor and the air inlet, it stops it blowing back through the carb when the piston starts it's down stroke. (They call them "reed valves" but they are really clacks).

A turbo charged 2 stroke is interesting. Of course you can't increase the cylinder pressure because the exhaust valve is still open when the inlet cracks, but 2 stroke power is all about flushing the exhaust from the cylinder. With fuel injection you wouldn't be blowing unburnt fuel down the exhaust if you over-cooked it.

OTOH what do beer swilling morons like me know about designing engines? :very_drunk:

[brsanko]

Okay, I'm back and my blood pressure is back to normal and I will learn to ignore unhelpful people. Yes the yoke is like the one in the Bourke engine, oddly enough I thought of it myself before I ever knew about the Bourke engine, but a few years ago I discovered the website for the bourke engine and it laid to rest my fears that the yoke might not work. I think my design solves some of the issues with the Bourke like vibration, and size.
I have a garage that is about 18' x 24' (I'm looking out the window guessing). It's full of junk but I'm pretty motivated to clean it out (not my junk). And if I need more my landlord has a building about 1/2 a mile away that is about 30' x 100' that I could use part of if I need to. It currently has a dirt floor and no electricity but the adjacent identical building has his cabinet shop with 3 phase power in it and it can be hooked up easily. My initial equipment budget will be $5-10k and I have been looking at mills and lathes on ebay and there are some deals to be had but I guess I don't really know what I'm looking for.
I'm sure I will start with some exercise projects and eventually make some scale models and mock ups of my design. The fuel injection system I have invisioned for the design as well as the turbo are not really DIY projects but I would like to work some of the bugs out of the basic design and prove it's viability before I try to do anything commercially with it. And if nothing ever becomes of itcommercially it will be an exciting hobby. Thank you all for your input.

[brsanko]

Tensen: It was not my intention to brag about how clever I am, and I don't mind constructive criticizm(sp?). I just don't need people going on about how difficult it's going to be, it's not constructive. Plus I'm sensitive and have a short fuse myself. I also am looking for advice on engine design, I'm not an expert in that feild either but I think I may have some good ideas and I like it when people look at them and critique them, as long as they're not just spewing out junk like "it won't work" or my very favorite "If it would work, then someone would have already done it, or they have and it didn't work." If you know what I mean. I understand most of the people on here are at least as smart as I am, if I didn't I wouldn't be asking them for help. I just wanted to let them know that I have the capability to learn this stuff. Any way back on topic, shrink session over lets talk about machine work.

[brsanko]

Actually it does have two combustion chambers on each cylinder that is pretty much the main unique feature. Why would the fuel be injected durring induction? I was thinking TDC. The direct injection would allow a computer controled so that fuel could be injected only when it was needed to maintain speed or to accelerate. Also don't forget it runs on diesel. I have the spots drawn in for the injectors (all 8 of them) but I don't have the injectors or lines drawn. As far as bore and stroke I just drew it square for the sake of a simple drawing I still need to do some research to optimise that but I imagine that a longer stroke would be better. I guess you'd be right whomever said that a turbo wouldn't work because the ports are both open at the same time so I guess it would just have to be a supercharger. That will actually simplify the design for me considerably.

[brsanko]

I didn't draw it this way but I was thinking the intake valves should be bigger than the exhast valves so when the exhast valve closes the supercharger can push in some pressure. I am as we discuss this planning to completely revamp my drawing (no small task in it'self.) to include some of the changes discussed.

[brsanko]

your crank looks to have no meaningful counterbalance
your inner cylinder ports wont pull as much volume as your outer ports because of the con-rod obstruction (not sure if that would be a massive issue)


I guess I assumed an opposed engine didn't really need counterbalance. If it does I have no idea how to design it. As far as the obstructed ports, I also don't really know if that would be an issue. I suppose I could flare the port and manifold on the inside chambers if I need to. I haven't put a lot of work into the crank design as of yet. I've only really been working intensively on the drawings a few months now so there are no details set in stone by any means. This is really just a concept drawing at the moment. I'm not saying I'm ready to get started building it. I'm just your average ADHD kid who needs to have 12 things going on to not get bored.

[brsanko]

BR i can see some issues with your design and position of TDC when firing happens. With everything being at opposing positions you will just end up with a pile of bits as it locks up upon detonation. I would look at a more traditional layout of the crankshaft myself.
Now this is the kind of advice I'm looking for. I currently have it set up so that the opposing pistons are basically one unit, so that each pistion assembly has 4 combustion chambers.(see pic) Would it work better if the piston assemblies were a few degrees off? More than a few?

[m_c]

I guess I assumed an opposed engine didn't really need counterbalance. If it does I have no idea how to design it

The opposing piston/rod assemblies will counter balance each other, however the crankshaft itself will still have offset masses flying around at great speed unbalancing things.

[m_c]

Now this is the kind of advice I'm looking for. I currently have it set up so that the opposing pistons are basically one unit, so that each pistion assembly has 4 combustion chambers.(see pic) Would it work better if the piston assemblies were a few degrees off? More than a few?

You need to consider power delivery. Each time a cyclinder fires, you get a high load followed by a power surge. This causes the crankshaft to deform, so it's got to be suitably designed to handle the peak torque. By having two cylinders firing at the same time, you'll be putting a lot more stress through the crankshaft.
Ideally you want power delivery at equal intervals, which would mean the two crank pins being 90degrees apart, however you'd have to take into consideration the crankshaft balance.

[blackburn mark]

Did you miss the 2 stroke part? There is no suck unless you do something really clever with the exhaust pipe geometry.


expansion chamber forms part of the exaust (the bulbus portion of a typical two stoke exaust) the inertia of the exaust gas (in the bulbus section) keeps its momentum forming somewhat of a vacume behind it drawing in the next charge

clacker valve :) reed valve we used to call them

"injecting at TDC" youll have to look into that one... im assuming that you would get better atomization at lower pressure (during induction or there abouts) at TDC the pressure would be quite high with it being a deisel



I currently have it set up so that the opposing pistons are basically one unit


i think your ok in principle but i would have thought a 45degree rotation on your crank timing so that your firing one charge at a time (higher frequency vibration but less amplitued than firing two charges simultainiously i would think)

crank balancing ..... errrm.... your on your own there :) im not sure if you just balance the crank or you take some of the piston and con-rod mass into consideration

[Robin Hewitt]

expansion chamber forms part of the exaust (the bulbus portion of a typical two stoke exaust) the inertia of the exaust gas (in the bulbus section) keeps its momentum forming somewhat of a vacume behind it drawing in the next charge

Traditionally a 2 stroke has the carburettor on the opposite side to the exhaust. The piston goes up producing a partial vacuum in the crank case, the bottom of the piston clears the inlet port and fuel air is sucked in . The piston descends and moments after the piston clears the exhaust it clears the fuel inlets which usually come up the sides connecting the crank case to the combustion chamber. You would think there would be enough heat to light the new fuel but I suppose the explosive decompression cools it somewhat and the mix doesn't really want to light until the pressure is up again. I'm actually rather surprised 2 strokes work at all, if they never existed and someone here came up with the design I'd probably pooh-pooh it.

I suppose you could use a supercharger to get the push, but you do need a push because the pressure must still be well high when the side inlets open.

Using exhaust to create a vacuum is steam locomotive technology but I'd say it could only ever be a helping hand in a 2 stroke, a bit of fine tuning, something to ease the back pressure, not enough to do the recharge.

In a steam train the exhaust comes up the blast pipe, into the smoke box, past the the ends of the fire tubes and up the funnel. What comes out the top is "steam" followed by smoke. What drives it is the valve gear shutting off the exhaust, the air simply doesn't want to stop so it carries on up the funnel drawing on the firebox. Unfortunately a funnel will only pull efficiently at one speed but the old boys knew that and filled the funnel with different size tubes to compensate.

[blackburn mark]

Traditionally a 2 stroke has the carburettor on the opposite side to the exhaust. The piston goes up producing a partial vacuum in the crank case, the bottom of the piston clears the inlet port and fuel air is sucked in . The piston descends and moments after the piston clears the exhaust it clears the fuel inlets which usually come up the sides connecting the crank case to the combustion chamber. You would think there would be enough heat to light the new fuel but I suppose the explosive decompression cools it somewhat and the mix doesn't really want to light until the pressure is up again. I'm actually rather surprised 2 strokes work at all, if they never existed and someone here came up with the design I'd probably pooh-pooh it.

I suppose you could use a supercharger to get the push, but you do need a push because the pressure must still be well high when the side inlets open.

Using exhaust to create a vacuum is steam locomotive technology but I'd say it could only ever be a helping hand in a 2 stroke, a bit of fine tuning, something to ease the back pressure, not enough to do the recharge.

In a steam train the exhaust comes up the blast pipe, into the smoke box, past the the ends of the fire tubes and up the funnel. What comes out the top is "steam" followed by smoke. What drives it is the valve gear shutting off the exhaust, the air simply doesn't want to stop so it carries on up the funnel drawing on the firebox. Unfortunately a funnel will only pull efficiently at one speed but the old boys knew that and filled the funnel with different size tubes to compensate.

ill buy that :)

[Swarfing]

Now this is the kind of advice I'm looking for. I currently have it set up so that the opposing pistons are basically one unit, so that each pistion assembly has 4 combustion chambers.(see pic) Would it work better if the piston assemblies were a few degrees off? More than a few?

Engine design is beyond my knowledge but i have rebuilt a few 1380's and couple of 1410 'A' series for group 'N' family saloon car racing. What I do know is that as soon as you start playing around with crankshaft timing on a week solution (stock crank) it all go horribly wrong :nightmare:

[blackburn mark]

im wrong on the "injecting during induction"
just read a document about a large two stoke deisel that is injecting into compressed air

[m_c]

A basic diesel engine will inject a good bit before TDC. Diesel is quite slow to ignite, so to get peak power and good air/fuel mixing, the fuel has to be ignited long before TDC (IIRC at typical slow idle it's about 18deg BTDC). This is why diesels knock so much, as the engine is pretty much on the verge of stalling at TDC due to the high pressure.

With modern common rail systems, fuel injection is now a multi-stage process. As the piston approaches TDC, a small amount of fuel is pre-injected, which results in an intial flame, then as TDC is approached main injection occurs as a further series of injections, which ignite quicker due to the already burning fuel.



As for diesel 2strokes, they have existed in the past. Some had conventional valve trains, some were ported, but pretty much all of them were supercharged.

[John S]

My Ex wife has An IQ in the 140 region but my Dog has more common sense and abilty to think out problems.

Jazz,
Does your dog have a sister ?

[jcb121]

clever boy :)

That engine is pretty clever, using manual rods from the crank to open and close ports.

So the piston is connected to one or both of the valves? If you made the valves come off the piston at 90 degress then you could have one cylinder with two expansion strokes as you could have a combustion area on either side of the piston.

[russell]

As for diesel 2strokes, they have existed in the past. Some had conventional valve trains, some were ported, but pretty much all of them were supercharged.
Diesel 2-strokes used to be used extensively for model aircraft without supercharging before the days of outrunner electric motors. I'm not sure how well they scale up though.

Russell

[Robin Hewitt]

Diesel 2-strokes used to be used extensively for model aircraft without supercharging before the days of outrunner electric motors. I'm not sure how well they scale up though. Russell

I think they ran on nitro, but maybe this one runs on nitro.

[mocha]

yep, model aircraft, hydroplanes, boats... they were and are still used today, mainly found in buses and marine engines and some main battle tanks. The "diesel" part of the model engine refers to the compression ignition rather than the fuel type. The fuel as I recall was nitromethane (or something exotic that now comes with a Health and safety warning if you can still get it!)

The flat fronted buses after the routemasters - the name escapes me, used the same engine design as the Chieftan tank, but that was with two opposed pistons for every cylinder.

[John S]

The flat fronted buses after the routemasters - the name escapes me, used the same engine design as the Chieftan tank, but that was with two opposed pistons for every cylinder.


The Leyland L60 that engine was like an hand grenade looking for a war.

main difference between small diesel two strokes and large is that in the small ones they use crankcase compression and need a fuel oil mix.
The large ones used pressure oiling like a 4 stroke but this precludes crankcase compression hence the supercharger taking over this roll.

[brsanko]

Actually a good share of commercial diesel engines are two stroke even today. Catapiller, and Detroit Diesel to name 2 big ones. The main concern with this design, I think, is that injection starts after the exhast port is closed, which I don't think will be a problem.

[brsanko]

clever boy :)

That engine is pretty clever, using manual rods from the crank to open and close ports.

So the piston is connected to one or both of the valves? If you made the valves come off the piston at 90 degress then you could have one cylinder with two expansion strokes as you could have a combustion area on either side of the piston.

Look at it again, there are no valves, only ports. There are already two combustion chambers per cylinder. The rods you see are the scotch yoke/connecting rod for the piston. Actually though if I had them go 90 degrees and then down I wouldn't have the difference in exhast flow on the bottom chambers.

[russell]

I think they ran on nitro, but maybe this one runs on nitro.
We used to make our own fuel. A mixture of paraffin, castor oil, and ether with a tiny amount of amyl nitrate if more power was needed.

Russell.

[m_c]

Diesel 2-strokes used to be used extensively for model aircraft without supercharging before the days of outrunner electric motors. I'm not sure how well they scale up though.


I wasn't talking about model engines. I was talking about ones that could power real vehicles!

[brsanko]

6257625862596260Well I took some of your suggestions and made some changes to my model.&nbsp; I staggard the cylinders, increased the stroke a bit, made the intake ports longer than the exhast ports, and completely redesigned the crankshaft and crancase, including some counter weights.&nbsp; I still need to redo the manifolds and induction system as well as add injectors and systems for cooling and oiling.&nbsp; I wonder if one could design the lubrication and cooling systems as one system.&nbsp; As in oil cooling, running the oil through a radiator and such.

[Jonathan]

You still seem to have the crankshaft running in bushings, assuming that's what the white pieces are? Surely you would want to use proper bearings, or is the temperature too extreme, doesn't seem likely? Fitting bearings seems a lot easier than making bushings and getting them all aligned.

[m_c]

I'd assume the ultimate aim would be to use plain bearings, just like a normal engine...

[brsanko]

I'd assume the ultimate aim would be to use plain bearings, just like a normal engine...

That's what I intended I just didn't do any research on what they look like.

[Jonathan]

That's what I intended I just didn't do any research on what they look like.

Fair enough, I thought rolling bearings were more commonly used in engines which now I've checked clearly isn't the case. There seems to be much discussion on various forums about their relative advantages and disadvantages.

[m_c]

Standard 'modern' plain bearings consist of two semi-circle shells of white-metal on an aluminium backing plate.

The white-metal acts as a temporary and sacrificial bearing surface in the case of no oil/metal to metal contact, as under normal circumstances there should be oil to provide a hydrostatic/fluid bearing.


The only modern engine where you're likely to find rolling bearings, are small two strokes.

[brsanko]

There does that look better?6277

[brsanko]

I guess what I'm really hoping for here now, seeing as I won't be looking for any equipment for a few months yet, is whether there are aspects of this design (other than the supercharger, as I will most likely outsource that) that would be particularly challenging to machine, or that should be changed for the sake of ease of manufacture. And of course any comments as to particular design funcionality or practicallity. Don't be afraid that I'll get sore, I really do appreciate constructive critisizm just not statements like "it will be more work than you can handle" or "it just won't work". Thanks you've mostly been very helpful so far. I just reinstalled windows so I have to also reinstall Sketchup. As soon as I do that I will export a pic of the manifold I have drawn. I'm sure it's all wrong but I have to start somewhere. Let me know how to change it and what the best way to fabricate it would be. Is aluminum/iron casting beyond the scope of the home workshop? I sure hope not.

[mocha]

I wouldn't go as far as "better" :-) You may also want to invest something to deal with the lateral (axial) thrust on the crankshaft.

Could you explain your thinking regarding the 90 degree offset of the crankshaft?

[brsanko]

Could you explain your thinking regarding the 90 degree offset of the crankshaft?
I guess that was what others suggested in order to keep everything smooth and balanced.


I wouldn't go as far as "better" :-) You may also want to invest something to deal with the lateral (axial) thrust on the crankshaft.? Any suggestion as to what?62896290

[JAZZCNC]

I guess that was what others suggested in order to keep everything smooth and balanced.

Did say I liked a good laugh. . :hysterical::hysterical::hysterical:

[irving2008]

Is aluminum/iron casting beyond the scope of the home workshop?

Not for small aluminium parts, but it takes years of practice to be able to cast something as complex as the parts you'll need. Also something the size of a crankcase is going to be hard to do in a home sized furnace. Making a furnace big enough is a challenge in its own right! And thats just for aluminium, iron/steel is a whole new ball game.

Whilst I applaude your efforts and ambitions (as someone who often bites off more than he can chew) I do wonder about your understanding of the complexity of the challenge. You are focusing opn the design and machinining of parts, but that is just the tip of the iceberg. I have some small experience of engineering and materials analysis from past experience of designing cold-wall heat-exchangers for cooling military equipment and I wonder how/when you are going to do the materials analysis and heat/cooling analysis to determine whether your design will work (clearances across temperature gradients, etc.) or will simply seize at the first run or, worst case, melt itself into oblivion...?


Personally, before you go much further, I would suggest you invest in a small mini-lathe and mill and see if you can make a working model of a single pot 2-stroke or steam engine to one of the many designs on the web. That'll give you far more insight into the skills/expertise needed than any questions on here.

[brsanko]

I was just talking about casting the manifold, it would be kinda heavy if I milled it. But yes I intend to to do just what you are suggesting. I am hoping this hobby is more complex and challanging than I ever imagined. If I thought it were something I could master in 5 years I wouldn't bother with it. I know I'm talking big and asking dumb questions, but how exciting would the prospect be if I were dreaming about milling aluminum key chains? Quite honestly I don't care if my first engine siezes up or falls apart (safty concerns notwithstanding) I'm interested in learning and comming up with new ideas and trying things that others think are stupid. That is how innovations come into being. How many brilliant inventions were dreamed up by big corperations following the rules and taking baby steps? NONE! To answer your question I'll probably do materials analysis after a few failed attempts at guess work. Will that bother you? This is a hobby, my intentions are to have fun and to learn. Why is everyone so concerned that I won't do it right the first time? Who the hell ever does? One guy says get the biggest lathe you can and another says get a mini one to learn on. I'm pretty sure I can learn just as well on a large one and from what I've seen on ebay it won't really cost me much more(I have friends with large trucks that will haul stuff as far as I like and I just have to pay for time and fuel so that''s not an issue. I think I'll start with a mill and a lathe and an assortment of accessories, and just start messing around. I've downloaded an assortment of books to read in the mean time to get some beginner project ideas. I'm just posting my engine design to keep ocupied for now. Why does everyone keep talking about "years of practice and experience" like they are a terrible thing that I can't afford? If I make my first working engine in 20 years I'll be ecstatic! Chill out and just humor me for Pete's sake.

[Swarfing]

Brsanko i admire your enthusiasm, i too used to get fed up with people telling me that is too difficult and requires skills etc. My first CNC machine was not built to work just to satisfy me that it could be done. After that i invested in a lot more kit time and energy amongst my very busy schedule. I cast most of my own lump material for machining in aluminium. Cast iron is a problem for me as most things in iron i would like to use is way too big to handle. Don't be put off but just acknowledge what they are saying as it is advice and at the end of the day you do not have to take it?

Don't forget the only dumb person is the ones that don't not ask the dumb questions and get no where. At the same time listening about others mistakes could save you a lot of heartache.

Don't give up or take things to heart, if people did not try we would not get anything done in this world :-)

PS

My first machine worked better than i expected and it made parts for my second one so goes to prove sometimes just doing can be the best lessons. I could cost a lot more buying proper training.

[irving2008]

...Why does everyone keep talking about "years of practice and experience" like they are a terrible thing that I can't afford? If I make my first working engine in 20 years I'll be ecstatic! Chill out and just humor me for Pete's sake.

You make a good point... its just for most of us either this is a hobby where money and time are limited so we focus on the art of what's doable and affordable; or its a business, where we focus on the art of what's commercially practical. You appear to be in a situation where time and money are unlimited. Thats great for you, but its a different way of thinking for the rest of us.

[bobc]

Horses for courses, some people will set small goals that are achievable and give a small reward, others will set a massive challenge and get a big satisfaction from it... if they achieve it. If you don't try you won't succeed, but trying does not guarantee success. There are some that know they will never achieve their goal, but enjoy the pursuit nevertheless.

The fact is that modern machines are so complex they require more knowledge than one guy can muster, certainly if building from scratch. The people you see running their own gas turbine are usually people with professional knowledge and experience.

The internet is a often a bear-pit, but you are open to public comment and everyone has an opinion, it is usually the naysayers who are motivated to post. There is something adversarial in human nature I think. Perhaps in some places most people say "yay, great idea, go for it!", while encouragement is nice technical criticism is also useful. If you say "my goal is X", then people are bound to point out the feasibility or otherwise. And I think most people feel obliged to warn someone if what they are doing is doomed to failure.

If you want to just do your thing, that's fine, but if you seek expert advice, listen to the advice. Filter out the purely negative points, build on the positive suggestions. It is entirely reasonable to suggest practicing on smaller, achievable projects, than going for the "big bang" approach. Whether in business, science or engineering, pretty much every success story has a history leading up to it.

[JAZZCNC]

This guy doesn't want good sound advice gained from experience he just wants you to blow smoke up his arse.!! . . . . He's clever he's got an IQ of 140 you know, so leave the Arrogant twat to gain the experience the hard way.!!

[brsanko]

This guy doesn't want good sound advice gained from experience he just wants you to blow smoke up his arse.!! . . . . He's clever he's got an IQ of 140 you know, so leave the Arrogant twat to gain the experience the hard way.!!
If you actually had sound advice to give you wouldn't waste your time harassing me. You're the only arrogant twat around here. You haven't given any advice, sound or otherwise, except "don't do it it's too hard". Why are you even on here? Are you trying to discourage everyone else from getting into your line of work so you can take over the world? Do you have nothing better to do with your time than to antagonize everyone you're envious of? I am listening and absorbing every bit of useful information I get and repelling the idiotic discoragement. You're just sore because you realize what an idiot you've been and you're trying to convince yourselve that I'm the idiot. Granted I know very little about this pursuit, I've stated that from the begining. You can take two roads here, you can encourage me and guide me, or you can puff yourself up and make fun of me for my ignorance. If you had all the knowlede and expertice you claim to have you would have taken the high road. If you continue to comment on my thread you will continue to make a fool of yourself. You wouldn't be laughing at all if you read the opinions of you that some of your "collegues" have expressed to me in PMs. Now go find a hobby that suits your personality better. May I suggest wanking.

[brsanko]

Okay, now to address the rest of you kind sirs, I apologize for the previous unplesantness. I shared my ultimate goals because that is what motivates me, but currently the goals concerned are, setting up a workable shop to learn in and eventually move on to bigger and better things. My budget to begin with is about $10,000. I have no current plans to make any money with the shop, it purely a hobby. For me success is merely trying and learning. Please continue to give suggestions as to my engine design. Considering I have never so much as disassembled an engine does not my design show some decent ideas? I digress. I certainly do not have unlimited money (not yet anyway) but I do have a good supply of time. How that saying go about idle hands? I am getting a nice chunk of money and have business plans that should keep me in a fair supply of cash. I live simply and would probably be content to spend a good share of it on this hobby. So far I have deduced that I should get myself a lathe and a mill. What other accessories would be essential to begin making things out of aluminum. Perhaps someone could point me to some instructional projects to get me started as well. Yes, I will do some searches on my own as well, but I'm here now addressing you so I thought I'd throw that out there. I will block Jazz so you will not be interupted by my reactions to his stupidity anymore (sorry, I have mental problems, my brain is a high performance machine and when it malfunctions it can be disasterous) thank you all for your helpful advice.

[Jonathan]

So far I have deduced that I should get myself a lathe and a mill. What other accessories would be essential to begin making things out of aluminum.

For both the milling machine and lathe definitely get a decent size one if you have the space. I got a mini-lathe initially, but I really only used it during the school holidays as the bigger lathes at school were so much better that it just wasn't worth it. Although your budget would get a decent CNC mill and CNC lathe, presumably you'll want to get manual machines and convert them as quite apart from the cost saving you will learn so much more about how they work by to start with using them manually.

A pillar drill would be useful and wont set you back much compared to the rest. The milling machine will clearly work (better) for drilling, but often it's handy to use a normal pillar drill as it's quick to set up and means you don't have to interrupt the milling machine.

A metal-cutting bandsaw is invaluable if you're working with reasonable size aluminium bar, which could well be the case if you mill the block from solid. I won this one (so it was good for the money!) but there are many other good ones cheaper on eBay:

http://www.axminster.co.uk/axminster-axminster-mcb1155hd-swivel-head-metal-cutting-bandsaw-prod719253/

[Robin Hewitt]

I think we have a bit of culture shock here. Don't want to give away too many secrets but we are an odd bunch in the UK, you have to be slightly self depreciating, arrogance is not tolerated. I think it is something to do with our women, I call it "bloke speak".

The language is full of expressions with deep meaning, call someone a "great steaming birk" or tell them to "get their finger out" and they won't care. Use the wrong words and you are asking for a fight.

If you get insulted, the easiest way out is to agree, costs you nothing, you would go up in our estimation.

Jazz doesn't reckon you can make this engine, suggest you call him a "great Jesse" or "big girls blouse", he will understand.

[brsanko]

I've spent most of my life being self-depreciating, and I find nobody takes you seriously. I guess I rather be thought an arrogant twat than a simplton.

[brsanko]

The fact is that modern machines are so complex they require more knowledge than one guy can muster, certainly if building from scratch.

Personally I think this is one of the problems with modern technology, it is too complicated. Often I think efficiency can best be achieved through simplicity. Once a simple machine works perfectly more machines can be added to it to work in synergy, insted of add more complexity to make up for the short falls of the simpler components. That is what I am trying to do with this engine design. Could it be a complete failure? Sure, of course. It probably will be, but what I learn from that failuer will lead eventually to a success. And I think this success will come from trying unconventional ideas and from simplifying the design. Basically I have this design set up so that the only variable in operation is fuel delivery. all aspects of it's performance can be controlled by an electronic fuel injection system with myriad sensors and meters telling the computer what it needs to know to deliver the exact right amout of fuel and air pressure to achieve maximum power, efficiency, and minimum waste and emissions. What can I say? I'm a dreamer.

[JAZZCNC]

If you actually had sound advice to give you wouldn't waste your time harassing me. You're the only arrogant twat around here. You haven't given any advice, sound or otherwise, except "don't do it it's too hard".

Ok suggest you go back and read post #4 now where does it say "don't do it, it's too hard" actually nearly the opposite.!! I even say I'm sure you'll succeed and wish you luck.!!

You seem intent on dismissing advice from people who have made you aware of there past experience and berrating them has egotistical Nah saying doom gloom merchants just because they didn't pat you on the back or tell you what toys to buy.!!

Now I don't give a flying fuck what some people on here (I can guess who they are anyway.!!), who don't actually know me think.!! . . .But those that do, know I'm possibly one of the most willing people to part with advice for those prepared to listen and have a bit of respect.!!. . . .They will also have gathered I'm the type that won't give you the stink off my shit if you have a bad atitude.!! . . . . Yours stinks worse than my shit so go forth and multiply. .:encouragement:

*** Oh still think it fucking hilarious that you would make a major major design change because someone who probably has very little experience suggest's it.!! . . . More hilarious is that you think it's better. .:hysterical: ***

[m_c]

Engine design is a very complex area.
Manufacturers are spending millions on engine design in order to meet ever stricter emissions, so don't even think it's just a case of getting the right amount of fuel in!

Modern diesels are far more complex than their petrol counterparts.
If you don't know what SCR, EGR, DPF, CR to name a handful are, and they're purpose, you really have a lot of research to do.

As for the basic mechanics, extensive FEA has to be done to ensure parts are as light as possible while still being able to withstand required loads. Lots of work has to be put into thermal design to avoid parts overheating or having problematic hot spots. And finally you have to make sure the parts are manufacturable without exotic processes.

I'm not trying to discourage you, I'm just letting you know of the lengths manufacturers are having to go to meet emissions. Each of those systems I've mentioned add substantial cost to every engine, and vehicle manufacturers are renowned for saving every penny they can, so they're not doing it because they want to, they're doing it because they have to.

[brsanko]

I understand the complexity of these things and I am trying to do as much research on these issues but there doesn't seem to be a whole lot of sharing when it comes to this kind of information. It seems like one of the biggest issues when it comes to emissions is ensuring the complete burn of the fuel while still getting as much power out of it as possible. The fact that with the scotch yoke instead of normal connecting rod design the piston spends more time at TDC this allows a more complete burn of the fuel as well as maximizing the power extracted from it. Couple that with the fact that there is less wear on the cylinder walls and pistons and rings due to a lack of pivoting, not to mention much less weight and size combining two combustion chambers in one cylinder and you have a small example of how a simplification of design can help with several issues with one "out of box innovation". I'm not by any means saying I've got it all figured out and know all the issues I'm just saying that making nonconventional designs as a hobby with no big dollar company at stake can yield results that penny pinching corperations may not even spend a minute thinking about. And if it all fails and proves alltogether futile, then I will have had a good time trying. I want to know everything, about everything, while it is obvious that this is impossible it won't stop me from trying.

[brsanko]

All of these issues and areas of research are what I am trying to learn about. I have done much researchand will do much more. The engine design I have is not a prototype, or a blue print, it is an idea. I am making it as detailed as I can so that I can understand and address all of the issues out there. I'm not presenting this and saying this is the thing! Sorry if I come across that way, I'm saying "hey I have an idea and it looks something like this, what do you guys think" I've tried finding information on emissions issues and various solutions and ideas, but honestly it's tough to find. I don't even know where to start with thermal tollerances and such. So I'm putting what I have out there and asking for help to find the rest. You have given me some things to think about and some places to start and that is what I am looking for. So keep the comments comming and be as specific as possible and please offer some sources for reasearch. Right now I've jest been looking for information from free sources, but in the near future I will probably look at buying some research material. I think everyone knows that paying for knowledge is the quickest way to get ripped off so I guess I'd like to know what the best sources are as well. I know people are going to suggest school but I really suck at school and I just can't handle spending a week learning to use the power switch and wear my safty goggles correctly.

[brsanko]

Thanks Chip. If you goto someone's profile page you can click on "ignore this person's posts" or something of the like. I've done that to Jazz and so now he can flap his gums all he likes and I don't have to see it.

[Tenson]

How about outfitting the milling machine with a rotary axis instead of getting a dedicated lathe?

Like this - http://www.youtube.com/watch?v=hlsR5h_7ct0&feature=related

If it could be flipped horizontally or vertically, you could do most work on that... any ideas how to get it to do that?

[m_c]

What you're basically proposing is a boxer engine (that's the general term given to flat engines with opposing cyclinders), with a scotch yoke crank/rod set-up and ported cylinders.

None of those havn't been tried.
Scotch yokes are problematic, because the slightest amount of play causes knocking. Reduce the play too much, you can't get oil in and risk seizing/premature wear, too much play and you can't keep oil in and it knocks. Wear is always an issue on scotch yokes due to the sliding components, and the only practical area I've seen it used is in relatively low speed hydraulic pumps, which start knocking when worn and under load. Now given that this part of the design needs to withstand millions of cycles (a quick calculation for 10'000miles covered at an average speed of 30mph and 2000rpm, works out at 40 million cycles), it needs to be able to withstand wear.
There is also the disadvantage of not being able to tune when peak torque is applied to the crankshaft. With a scotch yoke peak torque transfer will always occur at mid stroke, as that's when the crank pin is at 90deg to the applies power.
With a conventional con-rod design, and by varying stroke/con-rod length, you can alter where peak torque is applied to the crankshaft, which from memory is usually around 30-40% of stroke from TDC.

Ported cylinders also come with issues. The biggest issue being purging the cylinder of spent gases. With a 4 stroke, the exhaust and inlet strokes do that very well, whereas with a two stroke you're never going to get a clean purge. With both ports open, there is still an area of gases at the top of the cylinder which even with good porting/air flow management, isn't going to be purged too greatly.


I'm not saying those issues aren't insurmountable, but there are many reasons why the Otto-cycle engine is still the favoured basic engine design to this day.

[brsanko]

Yes, those are all points I've considered, although I don't know much about the scotch yoke wear charachteristics as the only other place I've seen it used is the Bourke engine and there isn't much information about that. You do seem to have missed what I think is the most unique feature of my engine, the fact that it fires on both sides of the pistion essentially making it a one stroke cycle engine. The reason I think this is a good feature is that it allows a small engine to produce more power and do so at low RMP. But like I said before I really want to learn to fabricate, and if this engine doesn't work out I'll still be into metal work.

[Swarfing]

By firing on both sides at the same time i think you will be fighting the laws of physics. Equal Pressure on oposite sides at the same time will have double pressure in the middle?????? something will go bang as each side will be fighting greater residual pressure moving back out on climb surely?

[brsanko]

Who said anything about both sides at the same time?

[Swarfing]

You do seem to have missed what I think is the most unique feature of my engine, the fact that it fires on both sides of the pistion essentially making it a one stroke cycle engine.

Ah I read this as both at the same time??????????

[brsanko]

Nope, just one side at a time, but because each side has a 2 stroke cycle each piston fires on every stroke.

[m_c]

It's still basically a two stroke, as each piston/cylinder takes two strokes to complete it's cycle. Just because you've stuck two opposite each other doesn't make it a one stroke!


As for the original equipment question, a milling machine with a 4th axis will manage most of the bits, however you're also probably going to need a lathe for some bits.
What you buy, will depend entirely on what size you want to build your prototypes.

[brsanko]

I said it's "effectively" a one stroke as each piston has power on each stroke. Obviously there are two strokes per cycle but each piston is doing both strokes at the same time(compression on one side, power on the other). I'm not talking about opposing cylinders/pistons, I'm talking about two combustion chambers per cylinder for a total of 8 combustion chambers, just so we're clear.

Eventually I want to build a full size model and I don't know if I'll have the money again so I want to buy the best I can right away.

[BikerAfloat]

Hi Brett, I'm a Newbie here to, so a hello to you.

Your post really grabbed my attention as I am an Automotive Engineer who has spent the last 20-odd years in and around engine development (10 at Lotus Engineering, the rest spread fairly evenly amongst Jaguar, Land Rover and Perkins Diesels). I have worked on both the theoretical side - carrying out engine and vehicle simulation, as well as the practical side of performance and emissions testing. I have a love for weird and wonderful engines of all kinds and despite all the evidence I have seen to the contrary in the last 20 years, I still retain a small hope that we will someday find a better solution to internal combustion than the Otto-cycle.

I have been really reluctant to inject some more reality to this post, especially in the light of the way it has been delivered to you and I'm afraid, received in previous posts, but my advice to you is please, please only look at the building of this engine as an interesting and diverting hobby and please do not even remotely consider any commercial applications for this engine, it has far too many flaws (even with computer controlled injectors) to get close to the performance of a conventional design mechanical injected design, let alone the state of the art computer controlled engines now being built.

The forces of Diesel combustion are quite frankly beyond a yoke of ANY design, the crankshaft was chosen many, many years ago as the best solution to convert linear to rotary motion, even before the internal combustion engine came about and for good engineering reasons. These were learned the hard way, by experimentation, breakage, the odd fatal injury and constant redesign. Take a look at early steam engine development, you'll find it nearly, if not totally, impossible to find a new way to convert linear to rotary motion.

I could go on with reasons for this designs impraticality, but I think enough has been said already and I think you would find the following much more useful than what could be construed as continued "nay-saying". If you do want to look at practical realities and ideas regarding the Infernal Confusion Engine, I can strongly recommend getting yourself a Bosch Automotive Handbook if they still do it new. Used copies are going from £17 to £199!!!! mine cost me £16 20 odd years ago! This explains(explained?) a lot of the (then current) technologies concisely. Also treat yourself to a copy of the "Heywood" Internal Combustion Engine Fundamentals book (£17-£160 from Amazon) and read through that to get an idea of what you are up against when dealing with internal combustion. These were and probably still are, very much referred to in the industry. I've been very ill and out of the industry for the last 6 years, so things may have moved on book wise, but the chemistry and physics will still be the same!

I would also once have recommended you contact the R&D department at Lotus for their ideas on it, When I was there 1990 to 2000, it was not uncommon to receive such requests for help and we would reply in a polite and professional manner even if the ideas were totaly crack pot and I have to say we really did get some weird stuff! If you are lucky and some of the "old boys" are still there, you might get some plain and simple advice for free! On the other hand things have changed there so much since I left, I'm not sure what response, if any, you would get now.

I would seriously start with small do-able jobs such as conventional 2 and 4 stroke models and see what issues there are in making those work properly before you embark on the task of an unproven design. You are on a massively steep learning curve, take it steady and keep it real!

Cheers,
Geoff.

[Robin Hewitt]

you'll find it nearly, if not totally, impossible to find a new way to convert linear to rotary motion.
There is one the steam engine fanatics are playing with :beer:

Mount your drive shaft on a couple of bearings.

Extend it forwards and mount a plate with more bearings so it is free to spin on the same axis.

Bend the shaft behind the plate. Tie the plate so it can wobble but not turn.

When the shaft turns the edges of the plate reciprocate so you can make an engine.

The transmission forces are horrendous but you can use monster bearings to compensate.

There are lots of movies on the web and they are quite fascinating to watch because you can go on adding cylinders 'til the cows come home.

[brsanko]

Thanks for the advice Geoff. I didn't consider your post naysaying because you backed it up with facts and real experience. I looked but could not find any information on the limitations of the scotch yoke. The books you recomended sound like exactly the kind of thing I would be interested in. I don't mind a steep learning curve as long as the information is available. It seems like all the books or websites I have found are either ridiculously simplistic or very specialized. I don't have my heart set on this design I just think that simplifying is the answer to many complex problems, a philosophy I believe Lotus has always embraced as well. Thank you very much for your insights and I hope to chat with you more. This engine is not my main motivator for getting into machine work it is just something to discuss while I wait for the funds. I also plan to purchase a 1970s Datsun Z(I'm afraid Lotuses are a bit cost prohibitive here in the US) and rebuild an engine from a 1980s 280ZX turbo to swap into it. I don't know if head shaving is a bit advanced for a newby like myself but I may try it. I am just the type of person who likes to create things and metal seems like a wonderful thing to create with.

[brsanko]

6712

I came up with a variation on the yoke that I think could solve some of the issues with not being able to deal with the stresses of a diesel motor. Instead of an open yoke that the crank slides in it has a round insert that spins inside the rod and off center on the crank. The diameter of the crank is half the stroke of the engine. I'm not sure if this increases or decreces the stress on the crank but the sliding and hitting of the yoke is gone.