6,23cc 2 stroke engine

[Kevork BOYACIYAN]

Hi everyone;
I'm Kevork a new member on HMEM, 44 years old and live in Istanbul. Actually I found this forum at 2013 while researching for carburetor. I have several drawings about 2 stroke engine which I began since 14 years old. My father is a lathe machine master so I learned many things from him. I start to work in a factory when I was 19 and became a CNC lathe machine programmer and operator in short time. Also I started to draw technical drawings of our products. I graduated from universty at same time. My factory was always develope so I started to useing erosion machine, CNC milling machine and learn 3D drawing and programming in time.
My father had a Peugeot 404 and he had a repair book "Manuel Pratique De Technique Automobile Peugeot 404 Essence". I don't know french but there was lots of dimensions about engine in this book. I decided to use 1:4 scale of this 1.618cm3 engine, with convert it to two stroke one cylinder engine. Briefly dimensions have been determined of my 6.23cm3 engine with 21mm bore and 18mm stroke.
As I mentioned above I started to my drawings with pencil and paper by hand, years later I digitialized them with AutoCAD and I complete with all components with Solidworks. Everytime when I saw a new machine, like erosion or CNC, or learn new technics, I drew all parts from the beginnig.
I complete my engine almost and I had a lots of photos and videos chronologically of the construction phase and I want to share with you.
I'm not tested my engine yet I will hope to run it while I sharing photos and videos .
I hope you enjoy it.

 

[Kevork BOYACIYAN]

I want to send a photo to give you an idea.

 

[Kevork BOYACIYAN]

Hi;
After my research I decided to make an ABC engine. It is occurs Aluminium piston, Chrome plated Brass cylinder liner. My piston has flat head, cylinder liner has a loop flow ports on it which contains two intake and one exhoust. Also there is a rotary valve on cranckshaft near the carburetor.

I want to share my piston and cylinder liner set manufacturing first.

 

[Kevork BOYACIYAN]

After some drawings now it's time to real parts. This is my aluminium piston. First I finished the outside diameter on lathe. Then I used an appropriate circular shaped wood with sandpaper inside it to polish piston. After that I put it on CNC milling machine to complete inner and downer details of the piston.

What is the best way for better presentation when uploading images? I'm not sure, it should be just small pictures or full images. Please direct me.

 

[xpylonracer]

Hi Kevork
Have you made the piston before making the Liner ? IMO it s best to make the cylinder and then the piston is made to fit, especially where chrome or other plating is required on the liner.

 

[Kevork BOYACIYAN]

Hi xpylonracer,
Yes of course, I just polished my piston but not completely. After I finished chrome plated cylinder liner I accustomed piston to liner. It looks like piston can entered in liner, while it is still not coated. But also hard chrome coating had a thickness.
Inside of cylinder liner was conical grinded, that provides easy movement between at middle and BDC but also tightness at the TDC point.

I want to send photos of my chrome plated brass cylinder liner now.

 

[Kevork BOYACIYAN]

Continue to send photos of liner.

 

[lohring]

That's an excellent design. You will learn a lot by building it. Accurately cutting the cylinder ports is a great exercise in setup and machining. You might be interested in the work of Jim Allen. He has been building high performance two strokes for years. His gallery is a wealth of information on what it takes to make a powerful engine. See the gallery at https://gallery.intlwaters.com/index.php?cat=10141 and even more information at http://www.modelenginemaker.com/index.php/topic,3890.0.html

Lohring Miller

 

[xpylonracer]

Hi Lohring, thanks for the links, I can't see any pictures on Jim Allens posta, do you know if they are in an album anywhere ?

xpylonracer

 

[KenC]

Nice work but your transfer ports (bypass ports) look very small if this is to be a performance engine.

 

[lohring]

The model engine maker site probably needs you to register to see images. There are quite a few in the thread.

Lohring Miller

 

[abby]

Very interesting , how did you chrome plate the liner bore ? what solution ,anode , voltage and current ?
Dan.

 

[Kevork BOYACIYAN]

Hi Lohring,
I'm very glad that you share Jim Allens links with me, there is lots of knowledge. I've been studying as much as I can since yesterday. I noticed that my liner have six fixing hole instead of four which many engines have, Jim advised eight. Also my liner have visible fixing lip at the top, as Jims liner. These made me happy. But also I have seen Jim pay attention to polish both liner and piston, that way I may not do on my engine.
The first thing I will do after first run of my engine is reproduce my piston liner set and also coneccting rod and cranck if necessary.

Dear KenC
Thank you for your advice , I will consider and make some modifications on it. It is more visible on a running engine that how effect to performance each modifications. After my first run, because of my deficiencies in polishing, I was already planning to produce it from the beginning.

Dear Dan,
I'm not plated and grinded my liner myself. I'm work in a factory, we have lots of machine and sometimes they needs to renovate, we disassemble and repair them. Some of the worn parts are send to an other company for hard chrome plated and grinded again to achieve its original dimensions. So I sended my liner to that company. Unfortunatelly I don't know much more than general knowledge.

 

[lohring]

Your design is missing the most critical component of a high power two stroke; the tuned pipe. Designing those is an art and science of its own. Don't worry, though, your design will perform very well compared to similar four strokes. I wrote a series of articles on high power two strokes that may interest you. The links are below:

Lohring Miller

http://namba.com/content/library/propwash/2012/November/#/14/
http://namba.com/content/library/propwash/2013/March/#/3/
http://namba.com/content/library/propwash/2013/October/#/8/
http://namba.com/content/library/propwash/2014/October/#/7/

 

[davidyat]

Lohring is right. I used to race two stroke racing motorcycles in the Southern California Mojave desert in organized events. It's an art to make an expansion chamber exhaust for two strokes. We raced mostly on and off the throttle, up hills, down hills and we needed low end power and grunt. So we would get expansion chambers for that. Racing two strokes on an asphalt racing circuit would require a different expansion chamber for high end torque as they were mostly on max RPM for max horsepower.

 

[Kevork BOYACIYAN]

Hi,
I'm grateful for your advices, this is my first engine, so I'm sure there is lot to change over time. I couldn't do it properly for some parts, or I designed it incorrectly. In fact, I know the importance of exhaust design, its not just a pipe to remove the exhausted gases from the engine. I drove 1976 Beetle for five years between 2003-2008. I've been looking for ways to get more performance from the engine. Under the carburetor there is a pipe that facilitates cold starts. This pipe joins the pipes coming from left and right side before entering the silencer. First and most easy way to get power is removing this pipe, this gives you app. 5 HP more. A huge gain in an engine with a total power of 35 HP.
Equal lenght pipes helpful, for four stroke engines also. Each exhaust suck coming gases and thus provides scavenging. So exhaust pipe is not just a pipe.
This will be a rc car engine, of course I prefer to have a high performance engine. I've already finished it with all components. I'm open to modify anything on it.Time will show everything.

I want to send some more photo about line and piston.

Thanks in advance for your suggestions.

 

[Kevork BOYACIYAN]

Now its time to con rod. Its material is 2379 hot work steel. It is quite hard without heat treatment, I prefer to use this materail, because I wasn't sure about the shape it would get after the heat treatment.

 

[Kevork BOYACIYAN]

Note for my previous message, there is another con rod seen on IMG_8120-1. This was my third attempt.

And Piston connecting hole can be seen in this message.

 

[Kevork BOYACIYAN]

Hi to all,
I want to send my crankshafts photos today. It's consist two parts. The long one is the main shaft, it contains inlet port below the carburetor and transmitting the power. The short one is just for to provide extra bedding and for start the engine.

 

[Kevork BOYACIYAN]

I start with a piece of 4140 steel bar on lathe then used a saw machine to seperate them. A note for the curious one, this sawing machine was belong my father, after he retired, I continue to use that in my factory. I'm not sure about its produce date, I guess at least 40 years old. Anyone who knows, please notify me.
After cylindrical parts finished and seperated I put them on CNC milling machine to shape eccantric and balance parts.