I4 3.1 cc question

[cr4k3r]

Hi, im new to this forum i read it and congrats on your work, all of you. Im a mecatronist, i want for a long time to build a 3.1 cc I4 engine, water cooled, oil pump, oil filter...etc (after i buy a lathe of course cuz now im low on cash , hope this winter). The main issue i got on my schemes is the ignition. I dont want to overcomplicate things with electromotor or alternator...its to much for that size...imagine its 65 mm lenghts x 30 mm width x 70 mm height all of it, BUT - i was wondering if i can make actually a magneto like a scooter has with a distributor. Is that all there is? Because of my calculation on this one, it has 5 mm sparkplugs, not much of voltage needed to actually spark. Main issue are the parts to build a magneto, an ignition coil and a distributor. Because its an exact copy of a real engine (maybe someday i will build the car around this engine) i dont want a big box under my engine, i just want it to run without any battery or other accesories because afterall its very very small :hDe:...its smaller than my palm. :fan:

What do you think? Thanks.

 

[cr4k3r]

Hi, im new to this forum i read it and congrats on your work, all of you. Im a mecatronist, i want for a long time to build a 3.1 cc I4 engine, water cooled, oil pump, oil filter...etc (after i buy a lathe of course cuz now im low on cash , hope this winter). The main issue i got on my schemes is the ignition. I dont want to overcomplicate things with electromotor or alternator...its to much for that size...imagine its 65 mm lenghts x 30 mm width x 70 mm height all of it, BUT - i was wondering if i can make actually a magneto like a scooter has with a distributor. Is that all there is? Because of my calculation on this one, it has 5 mm sparkplugs, not much of voltage needed to actually spark. Main issue are the parts to build a magneto, an ignition coil and a distributor. Because its an exact copy of a real engine (maybe someday i will build the car around this engine) i dont want a big box under my engine, i just want it to run without any battery or other accesories because afterall its very very small :hDe:...its smaller than my palm. :fan:

What do you think? Thanks.

noone? :wall: 1 more question...whats the best insulator for sparkplugs.

 

[GailInNM]

Magnetos have been done, but to the best of my knowledge none are as small as you would like. They are easy enough to scale on a mechanical basis, but the physics of electricity get in the way. You still need a reasonable spark gap at the plug and about 2 volts per turn on the magneto secondary it means that you will still need 10 to 15 thousand turns. Even with wire sizes down in the AWG 46 range that still takes up quite a bit of room considering winding requirements to keep high voltage arcs from occurring in the coil. Here is a link to one of the smallest magnetos available using modern materials.
http://minimagneto.co.uk/

On sparkplug insulators, many home constructors use Corian for the insulator. It is easy to obtain, easy to machine and works well. I have made over 30 plugs with it and some are still running with over 500 hours on them. Only hade a couple of failures and they were due to my machining and not Corian failure.

Here are links to drawings and threads of one that will probably be in the general size range that you will need. There are several other designs on HMEM as well.



Sparkplug cconstruction

http://www.homemodelenginemachinist.com/f14/tiny-i-c-engine-7397/
http://www.homemodelenginemachinist.com/f14/tiny-i-c-engine-7397/index26.html#post115891



Gail in NM

 

[cr4k3r]

Thank you very much. I was thinking of a dynamo from a flashlight...1,3 volts output, with a custom ignition coil would be roughly 3000 in a spark...the gap will be under 1 mm. I wish this was simple...but the formulas are not the problem. Like you said "Even with wire sizes down in the AWG 46 range that still takes up quite a bit of room considering winding requirements to keep high voltage arcs from occurring in the coil." very true. But i need to build a system small enough, i really want to eliminate facts of improvisation for electrical components. Your schemes seem very nice and very inspiring, but i will consume more space because the electrical system will be bigger cuz i have 4 cyl. with 2 camshafts, i dont want a box or anything the size of my engine or batteries (i want just to run on self power)...a simple battery is aprox. the size of it, i will have the electrical system bigger. I will have a distribution...and all others like a real size engine (exept alternator and starter...i dont have to tell you why), instead a dynamo, a custom coil, condesator 2000 picofarads and a distributor mounted on the engine, belted to the camshaft i think will spark. I can find higher voltage dynamos but they are bigger. I can put diodes for DC.
Thanks for sparkplugs info. Seems i will have to do a lot of work to my dimensions...they will have to be 3 mm on the inside and 5 out. By the way, how is teflon? Its more stable, higher resistance and temp. than corian. But harder to build from.

Thank you very much for your help, if want to add something i missed or got wrong please do, i need all the opinions i can get. Cheers! Thm:

 

[stevehuckss396]

I agree with the corian. I think it is far superior than teflon for sparkplugs. I make #8-40 (4.2mm) plugs for one of my engines. They work well.

The ignition and coil is another story. I put a sensor in my distributor that is TINY. The wiring comes out just like a full sized engine. The coil is only about 3/4 inch diameter by less than an inch and when fired with the CDI board it jumps a half inch gap. If you need smaller than that I cant help you. I have never seen smaller than that.

Anyway, best of luck and dont forget to post some pictures of your progress.

 

[cr4k3r]

I agree with the corian. I think it is far superior than teflon for sparkplugs. I make #8-40 (4.2mm) plugs for one of my engines. They work well.

The ignition and coil is another story. I put a sensor in my distributor that is TINY. The wiring comes out just like a full sized engine. The coil is only about 3/4 inch diameter by less than an inch and when fired with the CDI board it jumps a half inch gap. If you need smaller than that I cant help you. I have never seen smaller than that.

Anyway, best of luck and dont forget to post some pictures of your progress.

ty, im still on the drawboard...i dont have a lathe and i dont want to buy chinese crap...i was thinking to build it on a bench drill, some files, drills, mills etc because i have to start allready, i have all the drawings i need and cant start with my mind on the lathe i want...its 3500 bucks and i dont have that money...dont have a job because it closed due to taxes...so i live of football bets (dont laugh), i make roughly 500 buck a month.
It will take me 3-4 days maybe at best to build the crankshaft witch is the hardest to build (did it before...not build a crankshaft but a camshaft...took me 4 days working sleeping 3-4 hours max, flawless). I didnt do this manual (40% of time)...usually i had a lathe, was old and not very precise anymore, the gears sleaped and the slide was just off, i had to sell it for 1000 $ to build my "shop".
I dont know, im confused about the wiring and the ignition...maybe i will make some custom parts myself...though im not an electrotechnist....im a mecatronist, not generaly the same thing. I hope next month i start my "crap-milling" (drill machine and other manual tools). . It will be a though month...i will become a zombie. :hDe: Pictures will come dont worry, im also curious how hand made parts will look and feel. I think you are too.

Thanks !

 

[cr4k3r]

i have a stupid question that i will ask because in theory is simple but...practice is killing spree over a period. Can i do my crankshaft on this, i thought 'bout it last night? Dont ask me why i ask this because you have the answer in previous post. :hDe: I know the lathe but dont have one (money problems), can i really make that on a bench drill with files, drills etc... the final touch will be by hand...filing, milling, shine, mesurements...etc. ;D Wish i didnt sell my old, rusty with unprecise slides lathe, now im crying in the inside, i cant stop thinking if this can be made by hand with the help of the drill. Did someone do it before? Or any other complicated round parts? I keep thinking about the 5 mm round from inside the crank...i will have to drill it off to a point with a margin of +2 mm to come with the file and cut off the eccess edge (pffff).

 

[Swifty]

Don't write off all Chinese lathes as crap, I think that it's only the smaller bench top ones that you have to be wary of. My 10 x 40 lathe is made in china and is a very good machine, I don't have a readout and rely on the dials, and I find them no problem. The smaller ones tend to have too much clearance in the saddle and cause problems.

Paul.

 

[Wizard69]

ty, im still on the drawboard...i dont have a lathe and i dont want to buy chinese crap...i was thinking to build it on a bench drill, some files, drills, mills etc because i have to start allready, i have all the drawings i need and cant start with my mind on the lathe i want...its 3500 bucks and i dont have that money...dont have a job because it closed due to taxes...so i live of football bets (dont laugh), i make roughly 500 buck a month.

I have to second not writing off Chinese lathes. Nothing in this world is perfect, but for what you pay the lathes aren't that bad. However there is another option, that would be to build a lathe yourself.

It will take me 3-4 days maybe at best to build the crankshaft witch is the hardest to build (did it before...not build a crankshaft but a camshaft...took me 4 days working sleeping 3-4 hours max, flawless). I didnt do this manual (40% of time)...usually i had a lathe, was old and not very precise anymore, the gears sleaped and the slide was just off, i had to sell it for 1000 $ to build my "shop".

This is the problem with old lathes, many of them are worn out!

I dont know, im confused about the wiring and the ignition...maybe i will make some custom parts myself...though im not an electrotechnist....im a mecatronist, not generaly the same thing. I hope next month i start my "crap-milling" (drill machine and other manual tools). . It will be a though month...i will become a zombie. :hDe: Pictures will come dont worry, im also curious how hand made parts will look and feel. I think you are too.

Ahh yes the German milling machine route. Don't underestimate what you can accomplish with a file, hacksaw and the like. As for using that drill press I'd be very concerned about your safety. Nothing will ruin your day more than a piece of steel stuck in a body part or a body part stuck in a piece of steel.

By the way much can be done with a 4.5" right angle grinder to move things along.

Thanks !

As for that mention of building a lathe, the Gingery lathe is one example of a DIY approach to a lathe, starting from nothing. There are other approaches that can get you there also. To be honest, performance wise, the cheapest Chinese lathe is probably a better machine even if it is a kit. The bug benefit to the Gingery process is learning the various bits of the craft involved in machine tool building.

 

[cr4k3r]

Well...interesting post Wizard69. You made my moral go higher. Thing is i made a list on my mind and i can do it with no lathe : drill press,bench grinder, vice, saw, grinder, small biax with all accessories, files, taps and dies, drills, mills, i have them all, whats missing is a simple lathe.
"Ahh yes the German milling machine route" , funny. I will wait though for money to buy the lathe because i really dont want to go learning build my lathe, i have a lot on my mind right now.
What do you think...shoud i make my "manual" crankshaft out of round or square? I find complicated a bit the square because i have all the edges to round up with a file...the space is tight-5mm.
Very much thanks.

 

[Wizard69]

Well...interesting post Wizard69. You made my moral go higher. Thing is i made a list on my mind and i can do it with no lathe : drill press,bench grinder, vice, saw, grinder, small biax with all accessories, files, taps and dies, drills, mills, i have them all, whats missing is a simple lathe.
"Ahh yes the German milling machine route" , funny. I will wait though for money to buy the lathe because i really dont want to go learning build my lathe, i have a lot on my mind right now.
What do you think...shoud i make my "manual" crankshaft out of round or square? I find complicated a bit the square because i have all the edges to round up with a file...the space is tight-5mm.
Very much thanks.

Always be on the look out for a deal. Ten or so years ago when I bought my 9x20, I spent months with the want adds, Craigslist and what have you trying to find a lathe at the right price. Eventually I gave up and went with a harbor freight 9x20 sale. Almost immediately after that purchase all sorts of used lathes started showing up locally. They can be found if you can take the time.

 

[cr4k3r]

Today i made a test with a round file to a round steel bar (15mm), i set the point to 5 mm in middle and in 15 minutes it was a mirracle, immagine 30 minutes on it (more calmly than i did now for testing)...was impressed myself, didnt know i can do that, exactly 5 mm and no rough edges right in the middle of the bar, measured all around. I think i will suspend my idea of a lathe and start doing it/them oldschool style; by the way...i love it manual, not to many tools, much space, not a mess like before, no stress lathe broking down or money on parts of the lathe, in principle not to much worry. I will be glad to have a lathe, but i think i will not have this pleasure of doing all with my hands and mind, its a thrill. And it seems it doesnt take that long to make. I think takes more to set up the lathe for the job than just going for it manual (of course, for my tiny engine/s or parts its ok). If you gave me a lathe now i will put it aside and continue manual.You were right : i underestimated the manual tools.

PS : i marked the round bar in the middle with space for 5mm in finish. Turned it and made another one in the other section to give me a square in the middle. And with a soft round file i took the edges of that cube inside that i made, a little there a bit here, and it was all round : 5.013 - 5.015 at max with a calliper, not bad (maybe i was lucky).