building my very first engine

[allen56am]

Hi friends, I am in the process of building my very first engine, A Flame Licker Engine, It was a 20cc 2 stroke Weed eater engine, I am making it into a open crankcase and it will have a walking beam overhead to run the slide valve that will be on the cylinder head, My question is, The existing spark plug hole in the head is 12.75 mm, That's all most 1/2" Is this the correct size for my Gas/Flame hole, And should I leave it round or make it square or some other shape ?
34.56 mm Bore
25.01 mm stroke
1.34252" Bore
0.98819" stoke
Thank you guy's so much...

 

[Shipdisturber]

I would make it round. More volume can flow through a round hole and more even distribution of heat too. Curious as to what others will say that have made these engines.

 

[allen56am]

Thank you for taking the time to help me, I was thinking like you, But all the engines I have ever seen have a somewhat square hole so I was questioning myself.

 

[Blogwitch]

I don't think you will have much trouble with the shape of the hole as long as what you are controlling the inlet with has a good sliding seal to be able to produce the vacuum. Some use sheet shim stock, others use the material from feeler gauges, the one I am still half way through uses a graphite block against a ground face.

[ame]https://www.youtube.com/watch?v=Mi_T60n52jg[/ame]

What you have to be careful of is you must look for the easiest way for the flame to enter the cylinder.
Heat likes to go upwards, so the flame needs to enter through the side or from below, from the side, the flame is being sucked 90 degrees sidewards or from below, straight in. If you are trying to get it being sucked in directly from above, then you are trying to get the flame to turn 180 degrees and this might cause problems by sucking in cold air with it, which is a killer when referring to flame lickers.

Maybe you should have a look at Jan Ridders site and look for his flame lickers. He gives very good instructions on how they work.

http://ridders.nu/Webpaginas/pagina_ervaringen_tips_happers/ervaringenhappers_frameset.htm

By searching about on the page, you should be able to change everything to English.

John

 

[Shipdisturber]

I think this is going to be interesting! Don't forget to post a video whether it works or not because working or non working is very informative.

 

[allen56am]

Mr. Shipdisturber I am new to this site, Were would I post a video ?

 

[Shipdisturber]

You would have to post it on You Tube then you can copy the link address and paste it to your post.