a smallest and most complex engine.
engine has four camshafts HEAD, 16 cylinders, is built in stainless steel, brass and aluminum, and has 50 cc DISPLACEMENT 

That is freaking awesome !

sure it is sir.

 though  the model is good and the work is hard , even i was amazed initially but you will notice that it is running on air not on fuel , i have a doubt

notice the Fuel Tubing coming from under the turn table at 6:50 .. .

noticed initially when he stars the functioning ,

 
sir running on air how cum, can u please shed some light on this.
it is already said that the fuel tubing is around 6.50.

The doubt is indeed justifiable.

If you see the cam shaft (at 2:10), you can see that the cam lobes for the exhaust and inlet valves are approximately 180° apart. In an 4Stroke IC engine they would be about 90° apart.

The gear train also indicates that the crankshaft and camshaft are revolving at the same speed. (you can find that by seeing the size or no. of teeth on the gears) In an IC engine the camshaft is at 1/2 the rpm of the crankshaft.

The tube seen at 6:50 is for supplying compressed air.
On turning the crank, during the beginning of the downward stroke the inlet valve opens, allowing the compressed air to enter the cylinder, pushing the piston further down. On reaching BDC the inlet valve is closed. The exhaust valve then opens and as the piston starts rising up, the air (which has now expanded and at a lower pressure) is expelled out. These two strokes are then repeated again and again and for all those cylinders…..  that’s what makes this engine work….!!!...

 
toing
too technical for me to understand anything.

anyways welcome to rcindia sir.

Hummmm…… 

There are other simpler things that could help you identify, but then you couldn’t be 100% sure with those.

Like

- Can’t see any kind of ignition system.

- No sign of any burnt gas coming out from the exhaust… but then, it could be a clean burning engine…. However small engines are usually never clean.

- The sound that can be heard in the background seems to be that of clattering of metal….. there is no exhaust note……

- No means of lubricating. (you never leave the crankshaft open like that)
And so on……


I admit that there is lot of work involved in making it and it sure looks great, 
but it’s a pity that the person hasn’t made a full-fledged working IC engine.