Scale model Economy hit & miss engine builders wanted

[John Wood1Participant @johnwood1]

Whilst waiting for the weather to stop raining so I can get the engine outside to test on petrol (‘er indoors has banned petrol in my indoor workshop until the house is sold!) I thought I would just try it on Butane gas. I have tried on occasion before but couldn’t really get it to pick up and run properly, anyway, I thought I’d put a lighter inlet valve spring on, just to see. Well, I spun the thing just once and it burst into life, frightened the poor old dog it did. I ran it for about ten minutes doing various adjustments – as you do then shut it down and went for a cuppa.  Half an hour later I tried again, same result. Right, let it go cold, that’l upset it, not likely, off it went again and seems now to want to be reliable – after all this time! I shall of course try it on petrol when I can but maybe the main problems have now been fixed, time will tell.

 

Thanks to all

Regards

 

John

[MichaelRParticipant @michaelr]

Hi John, Good to hear you have got the Economy running, all your adjustments have come together, good luck with the trial run on petrol. Stick

[Engine BuilderParticipant @enginebuilder]

John, I told you gas was the way to go !

Glad to hear you have results.

David

[Anonymous]

Interesting information, thanks guys, which I have no doubt will help me when I get my Economy engine finished. Just need to make a few more bits, weld up a stainless steel fuel tank,  finish the design of my own ignition system, and design and build the spark plug.

 

I was planning to try running the engine on Colmans stove fuel. Not that easy to get in the UK, but the bigger camping shops seem to stock it. No idea what the fuel is, but I assume it’s a mix of the lighter hydrocarbons. Anybody tried this fuel?

 

Regards,

 

Andrew

 

 

 

 

 

[John Wood1Participant @johnwood1]

And finally…… Although the engine started on Butane gas as reported above, trying it out over a period of time did show that it was often difficult to start and even, on occasion, not at all which meant that there was still a problem to be resolved.  The symptom was that the engine would only fire occasionally when turning over and often not enough to enable it to run reliably.

 

It really sounded like ignition so back to the spark.  I had an inline spark tester which I made to Jan Ridder’s design and had previously checked that there was a spark available, but now I find it wasn’t good enough. With the tester in circuit and most of the workshop lights off (the dog thought I’d gone mad!) I turned the engine over and watched carefully, sure enough, most of the time there was a weedy little spark but on occasion a fat one appeared and the engine fired – problem probably identified. I had a condenser fitted close to the contact breaker which came with the coil however, I wired a 220n capacitor across this and up came the spark as you would wish. The engine started immediately and, having tried it several time a day for over a week it never fails to start, mostly first time. The running is smooth, hit – and – miss is steady and slow running excellent. Still havn’t tried it on petrol yet but am now confident.

 

Sorry about the waffle but I thought this might just help someone else

 

End of story?  We’ll see!

 

John

[Charles 2010Participant @charles2010]

Hi John and all others

I have just found this site and by coincidence have just ordered the “Economy Stationary Engine” for deliver of castings next week.

 I will take on board all that has been said and keep an eye on developments on this thread.

 Has any one pictures of the construction of the Economy Engine ???

[Anonymous]

‘Fraid not, but I’m always willing to discuss how I made a given part, which parts of the kit I threw away, and how I’ve altered the design.

 

In due course (tomorrow) I’ll post a picture or two of progess so far.

 

Regards,

 

Andrew

[Anonymous]

Hmmmm, trying to upload photos seems to cause the website to crash out. I’ll try again tomorrow morning.

 

Regards,

 

Andrew

[Ian S CParticipant @iansc]

Hi Andrew, I found I had to reduce the size of my photos, I think the max I can post is 1844 X 1250, but you prob know more about that than I do, I just find this stuff by ‘hit and miss’. Ian S C

[Anonymous]

Hi Ian,

 

I did wonder if my photos were too big; I was too tired last night to work it out. I got confused because one of the first photos I uploaded was 3488×2616, but just over 2Mbytes in size. I thought there may have been a problem as the Economy photos are the same number of pixels, but are a bit over 4Mbytes. Lo and behold, this morning the first photo uploaded, no problems; then the system started sulking again. So the other two photos have been resized to be about 2.5Mbytes. Bloody software!

 

The upshot is the photos of my Economy engine are now uploaded.

 

Regards,

 

Andrew

[Ian S CParticipant @iansc]

Same problem I was having exactly, too big and too late at night, the latest ones on the current hot air modifications is done with a web cam I got at a garage sale for $NZ5, I need to do a bit more study  on my camera. Ian S C

[Charles 2010Participant @charles2010]

Very good clear pictures Andrew.

Can you give any details on your crank shaft??

[Anonymous]

Hi Charles,

 

As far as I can recall I made the crankshaft to the drawings, but as separate pieces to be assembled. The parts were then loctited together, and 3/16″ silver steel pins were loctited though the webs where the shafts were located.

 

I made the webs from hot rolled EN3. I think the shafts were made from oversize EN8, rough turned and then ground to size.

 

Any other questions feel free to ask!

 

Regards,

 

Andrew

[John OlsenParticipant @johnolsen79199]

You don’t need to post pictures for web viewing at full camera resolution. However if you want to reduce the resolution you are going to have to use an editor, like Photoshop for instance, and I guess not everyone is familiar with this sort of thing. One thing to watch is that you want to save the reduced resolution one with a new name, so that your own copy is not reduced in quality as well.

 

regards

John

[Anonymous]

Been using Paintshop Pro for some years to edit pictures, it does all I need – Andrew

[John OlsenParticipant @johnolsen79199]

Yes, you don’t need the full version of photoshop by any means, and I didn’t intend to imply that. Quite often something suitable comes with a camera or scanner as part of the software package.

 

regards

John

[John Wood1Participant @johnwood1]

Yep, Paintshop Pro is all I use too. To find a typical picture size just find someone elses picture on the site, right click it and select Properties, this will give you both the size of the image in pixels and the file size. Just re-size your own picture in Paintshop (or whatever) and save it as a jpeg image.

 

Regards

John

 

PS.  Engine still running well !!!!!

Edited By John Wood1 on 01/10/2010 13:46:58

[Charles 2010Participant @charles2010]

Well I have now started the machining of the flywheels with one completed and the second will be done after I have made up the crank..

 

I have put photos in an album …  I hope they are the right size pictures …

 

 

[Charles 2010Participant @charles2010]

The instructions mention a “dummy” magneto.

 

Has anyone tried to make a suitable magneto with any success?

 

Regards Charles

[Charles 2010Participant @charles2010]

Has anyone any tips on the cutting of the internal keyway in the flywheels etc?

[John OlsenParticipant @johnolsen79199]

Depends what you have available, but assuming you don’t have a slotter attachment on a mill, there are a few approaches to consider. One is to find a piece of similar material to the flywheel, eg probably cast iron, and turn a plug to just fit the hole. It should be flush both sides. Loctite it into place. Now make a centre punch mark exactly on the line where the flywheel and plug meet. Drill through with a drill that is the same size or a little less than the desired keyway size. This should be good drill, we don’t want it wandering off, and this is also why the material should be the same. Once the hole is through, remove the plug.

 

Now you have removed 78.54 % of the material you need to, so get a square file and carefully file out the rest. The hole will guide you so you should be able to make a nice job of it. Have a piece of key steel the right size handy to try, it is usually not too hard to make a nice keyway like this. The ones in the shaft are usually no problem, provided you havea  vertical mill. If you don’t, the old time approach was to mark out and drill a hole at each end, then carefully chisel out the material between. I saw one the other night where the ends were square to match the key, which was a very neat fit.

 

regards

John

[Charles 2010Participant @charles2010]

Thanks for the advice …  That seems a lot more simple than making a broach or other cutting tool !

[JasonBModerator @jasonb]

I tend to plane the keyways out on the lathe, use a boring bar and a HSS toolbit ground like a parting tool but with a vertical cutting edge. You can use the drill method to mak elife easier before planning.

 

The 4 1″ long x 3/16″ wide keyways were done in this bit of steel using the above method.

 

Model Engine Builder had details of how to mak ea small magneto, or the Minimag will soon be available again from a UK source

 

http://www.minimagneto.co.uk/

 

Jason

[Charles 2010Participant @charles2010]

Thank you Jason   for your input on the keyway cutting  and the info on the minimagneto.

 

Have you any more details on the Model Engine Builder details of how to make one ?

[JasonBModerator @jasonb]

They do sell back issues which include plans

 

Jason

[Author]

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