Flame Licker Question

[allen56am]

Hi friends, I am in the process of building my very first engine, A Flame Licker Engine, It was a 20cc 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, What do you think the Flywheel size, ( Diameter & width ) should be, I will be making it from steel or stainless steel ?
34.56 mm Bore
25.01 mm stroke
1.34252" Bore
0.98819" stoke
Also, The existing spark plug hole in the head is 12.75 mm, Thats 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 ?
Thank you guy's so much...

 

[Blogwitch]

The first thing that should be done is to make a new piston, it should be an almost tight fit into the bore and then very gently lapped in so that it becomes a little freer.
This is the most important thing with a flame licker, don't get that right and it will fail to run as the vacuum power will be lost down the side of the piston.

John

 

[allen56am]

Thank you for taking time to help me, Are you saying the stock / original piston that came in this engine will be to Loose to make adequate vacuum to make my engine run ?

 

[Blogwitch]

Quite correct.
Yours most probably has a piston ring to take up the slack and form enough seal for the engine to run. Your original piston is most probably 0.002" smaller than the bore, you will require a piston that is more like 0.0005" to 0.001"smaller to allow the seal to form.

I don't want to piddle on your parade, but it might be easier to start from scratch and make the cylinder/piston from bar stock, or even the whole engine if you have already designed it.

John