Hi, new to this whole forum thing but as a diesel engine engineer (inventor/designer/developer) I thought I'd quickly reply to this interesting thread.

One of your respondents has already noted that the US guys are assuming gas = gasoline (I am sure incorrectly). Putting some gasoline into a diesel engine short-term is unlikely to cause any problem to the engine internals if the mixture is up to about 50:50; however it will most likely wreck the fuel pump/injectors (the most expensive bits of the engine). Since gasoline is almost the same price as diesel there will be no operational advantage, so why do it? And as one of your respondents noted - if it was a good idea the fuels would either come premixed or diesel engine makers would recommend it.

If as I suspect you mean gas = gas (methane, ethane, propane, butane, LPG etc) then many many diesel engines have been made to run on a mixture of gas/air with diesel fuel injected to provide the ignition source. This used to be called "dual fuel" in some circles. The gas needs to be admixed with the air (or direct injected in a controlled way), which is the main complexity of the conversion (other than the storage tank for the gas). The diesel pump remains the same and timing need not be adjusted; the extra energy in the gaseous fuel will give you increased tank mileage but of course you will have to pay for the gas - cheaper than diesel in Aus?

I've no idea who could do the conversion but the opportunity ought to be high on the agenda for any forward thinking country people with organic waste which could be put into a digester and a diesel gen set used for local electricity generation. Static installations are generally a lot easier than mobile ones, weight and space never being an big deal. During my training back in the late seventies I went to see such an installation at the Manchester sewage works, built (i think) in the 1920's and still going strong.

Hope that helps