Jan Ridders Pressure-controlled Two-stroke engine

[John Somers 2Participant @johnsomers2]

Arise Sir Jim !

Well deserved congratulations ! Your untiring efforts and tenacity have at last paid off. You must be over the moon (or is it under the moon ‘down under’ ?

You have given renewed hope to all ‘Debbie’ builders including myself. I can’t wait to get into the workshop to make a Jimbo piston.

Best wishes

John Somers

[Ian S CParticipant @iansc]

This is a mould for a bush with a 3/8″ bore being loaded with carbon impregnated teflon swarf fron the piece of teflon rod in the background. there are more pics in the albums, showing gear for making 1/8″ and 3/16″ bushes, I seem to have lost the 1/4″ mould, never mind the wee fellows have proberbly borrowed it.

    After packing and compressing, the mould is heated slowly until it starts to go blue, its then allowed to cool, its then unloaded and the bush is ready to use.  Ian S C

Edited By Ian S C on 15/03/2011 11:53:14

[Richard ParsonsParticipant @richardparsons61721]

Ian S.C Many thanks for that idea. Next time I need bushes I will try it.

They used the PTFE at one place I worked. They used to machine it but ‘Elfin Safety’ demanded that the place where it was machined should be isolated from the rest of the factory and at a lower air pressure. The people working there had to wear the full frog suits etc. Do not ask me why. We bought the bushes in from Tawian and closed that part of the machine shops. I think it was white PTFE.

[Jan RiddersParticipant @janridders31649]

Hello Jim,

Congratulations, not only with the relieving result but also with your never lasting perseverance!! I admire and like that very much.

Maybe and after all, the problenm was typical for 2-stroke engines where small deviations in geometries of piston top and/or transfer port can infuence the critical flushing process above the piston in a negative way. It is important that all (or most) burned gasses are flushed out of the cylinder through the exhaust opening (you know that for sure) and that’s what the fresh gas mix must do. But the exact effect of this kind of piston and port geometries are hard to predict. Sometimes you must have some luck with it also, at least when making simple IC models.
In fact the fresh gas mix is injected under some angle but opposite to the exhaust port so the chamfer/cutaway on the piston top must help to direct the gas mix as much as possible to the top of the cylinder. Therefore the top of the piston according to my drawing plan has a (hollow) chamfer also, so I wonder a little bit why that didn’t work out with your engine. But as said some small deviation can disturb the flushing process and then the engine can “poisoning” itself.

In fact this critical flushing process was the reason why I later designed a 2- stroke where the fresh gas mix is injected in the cylinderhead, so in the top of the cylinder, as far as possible away from the exhaust opening; the “Pressure Controlled 2-stroke Sabine”. I think this engine has a far better flushing process, but I am the last one to say that this engine never will cause any problem: I dare not to say that anymore after all these stories !!

Again my congratulations and the relief is also mine.

Jan

[Dan ParryParticipant @danparry52768]

Great work Jim – way to stick with it!

 

I too am slowly, but surely working towards finishing Debra. With my five year old boy on my heels most of the time, shop time is pretty valuable and an hour here and there just doesn’t cut it. It took me a year to build my last engine.

 

Anyway, I’ve been lurking around this post watching everyone work together and wishing I had some advice to offer. This being my first IC engine as well, I figure it’s better to listen at this point. It sounds like building the engine is only half the battle as it was with my Stirling engine. It’s all in good fun though. It sounds like I’ll get a good education out of the deal no matter what the end result is and that’s always good.

 

Well, congratulations again Jim. Hopefully the rest of us building this engine can post our video of our engine running successfully as you have.

 

Thanks to everyone for the wealth of knowledge you have shared so willingly.

Good luck John Sommers, John Wood and all those working towards the goal of having this beautiful engine running.

 

Thanks again,

Dan

[John Somers 2Participant @johnsomers2]

I can hardly contain my excitement at finally having succeeded in getting my Debbie to perform as Jan intended. The final chapter on this ongoing saga can be found at http://start-model-engineering.co.uk/.

As a bonus I also found a cheaper and to my mind a better fuel for our IC engines Aspen 2T and 4T fuel. Anyway much more info on my site at start-model-engineering.co.uk

 

Thank you to one and all for your interest and support.

 

John S

[Jim GreetheadParticipant @jimgreethead]

In case anyone was wondering, I did finally get around to painting my version of Jan’s engine and you can see it here:

 

http://www.youtube.com/watch?v=o-zo52flDbI

 

It is still rather sensitive to fuel level but at least it runs. The screw that needs constant adjusting in the video is a form of throttle – it adjusts the maximum lift of the ball valve which I have relocated in the bit going into the fuel tank.

 

Thanks again to all of you who gave me advice and encouragement along the way. Without your assistance, it would have been just another doorstop.

 

Jim

 

[John Somers 2Participant @johnsomers2]

Debra sure looks good in her new finery and all ‘blinged up’ in those original colours. A true lady.

 

Job done and in great style.

 

John S

[Mark Foster 1Participant @markfoster1]

just a thought here in Australia the fuel is crap ! try Coleman camping stove fuel .its more volitile than the un leaded stuff .More like the old Super . try this little test .dip your finger in the fuel and blow it .with the Coleman and old Super it gets cold ! with the new unleaded it bearly even evaporates

[Jim GreetheadParticipant @jimgreethead]

Thank you John, it is nice to have the video where the paint is not too badly chipped and the shiny bits are still shiny. But I wish it would run as smoothly as yours.

 

You are right Mark, the unleaded stuff won’t work in the old motorcycles either. I tried Premium but it left a horrible residue so I am using Coleman fuel (aka Shellite here in Australia).

 

It won’t run with any extra air either which sent me looking for air leaks particularly around the bottom seal. But I have good compression at both ends of the piston travel. But having just re-read the earlier posts, I might try the suggestion from Dick Parsons and try some soapy water (or kid’s bubble mix). You never know. Thanks Dick, sorry I missed you earlier in the year when I came through Hungary.

 

Jim

 

[John Somers 2Participant @johnsomers2]

Mark

I don’t imagine the fuel in the UK is any better. I had a problem finding Colemans although I finally found some on the internet which worked out around £9.00 per litre including shipping.

Having used up a litre of Coleman fuel during my efforts to get Debbie to run I was googling for a local supplier when I came across Aspen 2T a ready-mixed (2%) alkylate petrol for all 2-stroke small capacity engines with a recommended mix of 2% or 1:50. (There’s also Aspen 4T for four strokes).

5 litres cost me under £16.00 and as Aspen fuel is much more widely available it saved me a package on postage costs. I was surprised to find that compared with Coleman fuel Aspen runs on a much leaner mix. With Colemans I was having to virtually close the vapour carb air valve to get Debbie to run. With Aspen the valve is just about fully open. She ran sweeter and uses far less fuel.

I am also informed that Aspen doesn’t deteriorate with age like conventional unleaded.

I understand that Aspen is produced in Sweden and although its widely available in the UK I don’t think Jim had any success in finding any in Australia.

If you are interested in my experiences with Debbie you’ll find the full story at http://start-model-engineering.co.uk/category/jan-ridders-simple-two-stroke/

 

Jim

 

Mine doesn’t run any smoother than yours and I note Debra also requires a restraining finger just like Debbie.

 

John S

 

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