Interesting idea, but I don't think I'd try something like that. For one thing, you have no idea where the pistons happen to be, or which way the crankshaft would try to turn. Lighting off a few drops of gas in a cylinder could also bend rods, or maybe even crack a cylinder wall if the piston was not free to move.

I remember one COLD winter day (temp close to zero) when I was trying to start a 1960 Dodge 361 V8 that had stalled on the side of I-40 and had been left to cold-soak overnight. After running one battery down and pouring several ounces of gas down the carburetor we decided we didn't have enough cranking speed. With a little creative jumper cable connecting I hit it with 24 volts. LOTS of cranking speed now! After clearing the flood and getting plenty of spark to the plugs it finally fired- - - - - -all the way through a big hole in one piston and into a crankcase full of gas fumes!

The oil filler cap whizzed past my right ear, close enough to feel the breeze as it went by. We never found it! A 12 gauge shotgun blast would have been quiet by comparison, and both valve covers bulged up like sausage links on a hot grill!
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!