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Jan Ridders Pressure-controlled Two-stroke engine

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John Wood116/05/2009 14:54:41
116 forum posts
Hi all, great to be on the new ME site isn't it?
Has anyone built the 2-stroke i/c engine from the free plan in ME last year? Also the petrol vapour carb to go with it? I have and it all went together very well indeed. I have coupled it to a trembler ignition system but simply cannot get it to start, or even fire!
I have checked all the dimensions, ports, inlet/outlet considerations, compression, back pressure (all according to Jan's own website). Timing is correct although many settings have been tried. A commercial spark plug is now in situ and fresh petrol - with and without oil - has been tried. I have driven it from an electric drill and suitable rubber drive belt, IT JUST WON'T COUGH!
I am quite new to the world of i/c and presume there are things going on which I don't realise so, anyone have any ideas please? 
All the best to ME from

Edited By John 1 on 16/05/2009 14:55:57

Peter Fitch19/05/2009 23:18:44
3 forum posts
2 photos
Hi John,
I to have made this engine and it looks very good. But like you I cannot get it to fire. I am using a piezo crystal from a gas lighter which seems to give a good spark.  This is my first IC engine. I quite thought that with a quick turn it would be away. Its difficult to know where to go from here. I have put a picture in my album. Maybe I should stick to steam, I can get them to work.
David Clark 120/05/2009 07:58:31
3357 forum posts
112 photos
10 articles
Hi There
I will see If I can contact Jan Ridders.
Sounds like a problem with a design fault perhaps.
regards David
GarethP20/05/2009 09:24:33
5 forum posts
Just a thought - if you've got a good spark at the right time could it be that the fuel isnt getting to the cylinder?
Peter Fitch21/05/2009 17:57:52
3 forum posts
2 photos
The design relies upon petrol vapour being sucked up into the cylinder from the fuel tank, not neat or atomised petrol. Its difficult to tell if this is taking place as you can't see it.
Jan Ridders21/05/2009 18:35:12
24 forum posts
5 photos
Hello John, Peter,Gareth,
This is Jan Ridders, designer of the Pressure Controlled 2-stroke. I just signed-in to this forum today on request of David Clark. I see that you have problems letting this engine run and that's a pitty because it can run super!
I invite you to contact me by e-mail :
The reason for that is that I can better understand your problems when you tell me somewhat more and, for all, that I can attach pictures and a demo video to support and illustrate my advise in trying to solve your problems. If we succeed in that I am willing to summarize the solution in this forum too, possibly helping other poeple having the same problems.
I already can say that there are no design faults since this engine is made several times already by others and with success according to this drawing plan. So there must be something overlooking  I think.
Friendly greetings from Holland and forgive my poor English.
Jan Ridders

Edited By Jan Ridders on 21/05/2009 18:39:16

Jan Ridders21/05/2009 19:16:42
24 forum posts
5 photos
Hello John, Peter,Gareth,
Here I am again,
May be you guys don't know about the existance of my web site
There I have pages for all my engines, inclusive this "Pressure Controlled 2-stroke engine"  with full descriptions, pictures, video's, animations and tips in case of trouble. May be this can help you in the first place.
Go for this engine to the chapter "Internal Combustion engines" and then click on the picture of this engine in the overview page for IC engines. On top of each page there is a button "English". If you click on that the Dutch text will be replaced by (my) English.
Apart from that you are welcome to contact me by mail as I said in my previous message.
Jan Ridders
John Wood122/05/2009 16:04:45
116 forum posts
Many thanks to all who have replied to my problem.
Interesting Peter to hear that you are using the piezo electric ignition system as originally described. I was going to use this myself but, after reading a later description by Jan on his website I decided to go for the trembler instead as I already had one to hand. I will follow up the other suggestions and WHEN I get it going will post the results here.
Gareth - thanks for the ideas. I have checked the ignition timing many times and am confident that all is well. The spark is excellent as well but I think the problem is more likely to be with the fuel as you, and Peter suggest. Will press on.
Thanks to you David for offering to help although I can't see any obvious design fault. I guess it's like most small i/c engines, they are the very devil to get started with the normal type of carburettor, I was just hoping the petrol vapour design would help in this respect and I still think that it will, we just have to get over this teething problem.
Many thanks to Jan for taking the trouble to make contact. I will certainly get in touch by e-mail and would very much appreciate any suggestions you may have.
Thanks to one and all
Regards  John
Peter Fitch22/05/2009 16:53:33
3 forum posts
2 photos
Although Jan suggested emailing him directly, I am posting my question here so others can see it.
I have built the air intake on the carburettor with the bottom pipe not touching the fuel as the drawing shows. On Jans website his model shows this pipe immersed in the fuel, almost touching the bottom of the tank. This gives the fuel a frothing effect when running. Should I modify mine or should it run with either design?
My congratulations to Jan for his engines (as shown on his website), they are quite remarkable. 
John Wood123/05/2009 09:57:20
116 forum posts
I think the version on Jan's website is an early one. Reading up on the subject it seems that an improvement is to be had in taking only the vapour without the bottom pipe being immersed. I also note that there is a further improved version which details a different control valve arrangement but have not tried that yet because I havn't got the details from Jan despite a couple of e-mail requests to him. I expect he gets a bit inundated at times so I must be patient, anyway the version as published obviously works so I would like to get that running first and perhaps try the new one later on.
Jan's website is well worth visiting (see above) for those who havn't yet.
All the best
GarethP23/05/2009 10:01:57
5 forum posts
Hi Peter,
I would use what Jan uses, mainly as it's proven to work - I would expect the frothing to greatly increase the amount of fuel in the air.
I've just had a look at Jan's site - the hit and miss engine is great!
Jan Ridders23/05/2009 10:32:16
24 forum posts
5 photos
John send me a mail to my local address and I gave him the answer below:
Hello John,
As far as I can see you did the right things trying to let this engine run. One of the things I can't see is mechanical friction in the whole system.

Two remarks:

1. I have my "standard" remark concerning the mechanical frictions when I send my drawing plan for this engine to somebody, and this is important:
The pressure Controlled 2-stroke engine is a very special and nice running engine; it is one of my favourites. But the power is limited because of the small cylinder content of 4.5cc. Therefore it is important that the whole mechanism is running smooth with low frictions; it must run "as driven by the wind". That is the reason why there are no rings on the piston; not necessary if you make the clearance equal or smaller than 0.05mm. I made a demo video to illustrate what I mean by low friction in this case; see attachment.

2. I did try a piezo ignition first indeed for this engine as I implemented successfully for my Otto and Atkinson 4-stroke engines. But it didn't work well for this Pressure Controlled 2-stroke and I still don't know the exact reason for that. I only experienced with my other 2-stroke engines that they all need a powerful spark to run well. Looking at a piezo spark it looks good but the power of it is much lower than that of a classic high tension coil as used in (classic) auto cars and motor cycles. These high tension coils are somewhat more bulky but all my engines run very well on it and if you use a rather small coil as used for classic motor cycles you can build it in the wooden base of the engine. I attached a picture of such a high tension coil. On this picture you can see also the much smaller coils presently used in light mopeds, grass sewing machines,etc with what I have bad experiences; they are made for different supply voltages mostly generated by a generator on the crank shaft and sometimes there is some electronic circuit in between also. So use the classic coil for 6 or 12 volt battery supply. May be that's what you meant with the "trembler ignition system"; I did not know this word.

I will put this answer to you in the Magazine Forum as well, but as said I can't attach the video and the picture there as far as I know.

Friendly greetings from Holland and don't give up!
Jan Ridders

Jan Ridders23/05/2009 10:44:14
24 forum posts
5 photos
Hello Peter,
Indeed there are to possibilities for the air in-stream pipes on the tank of the carburetor: the one that is immerging the fuel  making bubbles and the short one whith what  the air is streaming over the fuel surface. The engine will run with both pipes but in case of small engines with moderate speeds (like this one) I now prefer the short one. I have strongly the impression that the concentration of petrol vapour in the gas mix is more constant with this short pipe and that the carburator adjustment  while starting-up and regulating the engine's speed sis significantly less sensible.
For much bigger engines with relative high speed the bubble pipe might be preferable.
I am learning every day too.
Look at my answer to John too Peter, may be it can be of use for you also. If you send me a mail to my local address I will be glad to attach the video and pictures.
Jan Ridders
Jan Ridders27/05/2009 08:38:03
24 forum posts
5 photos

Hello Peter, John, Gareth,

I made a new video of the Pressure Controlled 2-stroke engine with a small "trouble shoot demo" at the end of it. When I send somebody the plan for this engine I now add the following remark:

""The pressure Controlled 2-stroke engine is a very special and nice running engine; it is one of my favourites. But the power is limited because of the small cylinder content of 4.5cc. Therefore it is important that the whole mechanism is running smooth with low frictions; it must run “as driven by the wind”. That is the reason why there are no rings on the piston; not necessary if you make the clearance equal or smaller than 0.05mm.
At the end of the video below I illustrate what I mean by low friction in this case:

Jan Ridders
Jan Ridders27/05/2009 08:52:07
24 forum posts
5 photos
A more general remark about the spark:
It is my experience that especially 2-stroke engines need powerful sparks.
You can have a very good single spark when you turn the fly wheel by hand. But in rare occasions it can happen that you don't have good and/or regular sparks or even no sparks at all when you turn the fly wheel with higher speed, for instance when starting-up with a hand drilling machine. A possible reason can be that you use an electrical switch in the circuit that is "normally open". That means that there is only a current through the primary coil during the very short time that the (small) notch on the cam disk is pressing the switch. It can happen that the electro-magnetic field in the high tension coil is insufficient then, depending on the type of the coil.
Another possible reason is that there is some spark flash-over to mass anywhere else in the circuit without seeing that.

To be absolutely sure that there are regular sparks I made a simple spark tester that you can connect between the spark plug and the high tension cable; see the page on my web site:

Jan Riders website

In fact you make a very little spark in series with the spark on the spark plug. It did help me already sometimes debugging problems and/or to be absolutely sure that there is a regular spark on the spark plug. The energy of the spark in the tester is so low that it doesn't affect the running behaviour of the engine, although it not the intention to keep it connected if everything is OK of course.

Most probably this is not case with your engines but you never know and eliminating possible causes is helping also to solve problems.

Greetings from
Jan Ridders

Edited By David Clark 1 on 17/06/2009 17:09:17

Henri van der Riet09/06/2009 11:45:12
3 forum posts
Can i reccoment that you guys, building Jan's desing, use both plans - the one from the MEW magazine and the ones that Jan can mail you on request from his website.
I found that the detail from both combined makes life much easier. But note that some dimentions ware different between the two- as Jan is entitled to change, because he's the master .
I've laminated his mailed designs pages back to back for use in the workshop and use the MEW ones as a supplement.
PS: Using a Hall sensor and magnet with a CDI or Transistor Ignition, will completely elliminate the extra frictions and spring forces of the mechanical breakers or peizo ignition options.
John Wood109/06/2009 15:51:58
116 forum posts
Thanks for the advice Henri, I hadn't realised that Jan had produced a slightly different design so that's useful to know. You make a good point in that using a Hall Effect ignition system will elliminate all friction from the cam so I reckon that's the way I shall go next.
seems an excellent site suggested to me by  Stick,  See thread entitled "Ignition coils for small engines". I have had a look and the units seem ideal so I just thought I would post the details here in the hope that it may help others. I hope to have a go with such a device soon.
All the best,  John

Edited By David Clark 1 on 17/06/2009 17:10:33

Jan Ridders09/06/2009 18:02:45
24 forum posts
5 photos
Hello John,
This CDI ignition system looks  very nice indeed, but rather expensive isn,t  it? In a model store in my neighbourhood they ask me 120 to 150  Euro's for it!
Till now I use a small micro switch that needs hardly any force and I buy second hand high tension coils used in classic motor bikes (indeed not always that easy to obtain).Somewhat bulky but you can build them in the wooden base of the engine. And this makes very good spark in any case.
I am looking for small and payable solutions for spark ignition all the time so I keep interested in anyones experiences with this. I used a piezo element out of a gas lighter successfully for my 4-stroke models but for one reason or another it didn't work  well for my 2-stroke engines despite a lot of investigations and numerous discussions with colleague model builders. Another thing with a piezo is that they need rather high  forces to press them and that could be a problem for very small engines. 
Greetings from Holland,
John Wood117/06/2009 15:30:37
116 forum posts
Hi Jan
Yes the CDI system is a bit expensive I suppose but at my stage it is more important to me to get engines working. I have spent a long time on the 2-stroke and really do want to get it running so I am prepared to spend a bit extra at the moment.
I have just finished the precision tapping stand I was making Jan so am about to go back to the 2-stroke engine and carb and try out all the suggestions you have made.  I have ordered a CDI ignition system which should arrive in a day or two and I will try all this out soon and report back.
Thanks again for your help
Jan Ridders19/06/2009 07:40:32
24 forum posts
5 photos
Hi John,
I am curious about your experiences with the CDI ignotion system and I sure hope you will get the 2-stroke to run one of these days. Don't give up!

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