If I put hydrogen gas in any internal combustible engine that use normal fuel or even a diesel engine, would that mess up the car?
Traditional combustion engines can run on numerous fuels, and gases work very well. Hydrogen is being tested by a number of manufacturers on fairly traditional engines. The engines are usually 'built' however - harder valves/stems/springs, uprated conrods, pistons, bore sleeves etc. Also obviously the injection system is different (I believe they use a gas mixer, or others use adapted DISI systems). You end up with lower emissions, lower burn temperatures, and higher power outputs.
Now how to store such an energetic element as hydrogen... that's the $150-billion question. The atoms pass straight through most storage containers we have currently, that aren't supercooled with liquid nitrogen.
Edit: Also Mythbusters once tested this on a completely bog-standard chev (I think?) v8, by spraying hydrogen straight into the carburettor. They nearly exploded themselves, but the car did run.
How would you obtain, store, and deliver hydrogen to an engine? I think BMW and a few other automakers tested Hydrogen as an alternative fuel in the mid 2000s and killed the project because the infrastructure to support a hydrogen vehicle does not exist in scale.
Some time ago I was looking at purchasing a CNG car. At the time people told me it would be too expensive to retrofit a vehicle but you can find CNG cars at municipality auctions and Honda made a CNG civic. Also chances are good you can find at least one CNG station in a mid-sized city.
Not sure if a CNG car could be converted to hydrogen, but they do have high pressure tank and are tuned to burn a fuel that is more similar to hydrogen than gasoline ( my guess, I am not a chemist or engineer)