Shakib,

A glow engine IS NOT a half Diesel.

The ignition results from a catalytic reaction of the platinum in the glow element, on the methanol in the fuel.
The methanol breaks down and heat is released, keeping the glow element very hot.

The heat of the burn will not suffice in keeping this glow element hot. If you use gasoline/petrol in your glow engine, it will run ONLY when the battery is connected to the glow plug. The engine will shut down as soon as you remove the plug driver, despite the higher burn temperature of the petroleum fuel.