Sory fo my english...
Maybe explosion wos wrong word, "ekspanzija" in my languge, if it is expazion in english, well, it is not my profesion to talk about it...
http://hr.wikipedia.org/wiki/Eksplozija
On race cars and motorbikes we can see it during day, also whan you squezze the engine in way it is not ment to be used, flames are normal...