If you could build/ rebuild an engine to run on wood gas ONLY what would you add and what would you take away? Not only from the engine but also other areas of the truck?
I am in the process of converting a Onan Diesel generator to run on wood gas. This involves to major changes to the engine, 1st is adding spark ignition, 2nd is changing the compression ratio.
The original fuel pump is being gutted and parts made to adapt a distributor from a Toyota car engine. Where the injectors where normally located need to be drilled out, tapped and spark plug inserts fitted. I cant just drill and tap as there is not enough metal. Changing the compression ratio from the original 19 to 1 to 17 to 1 will give much greater efficiency and increase the horsepower. According to work done by All Power Labs they where able to get a Diesel converted to woodgas to produce just as much horsepower as it did when it ran on Diesel. To measure the volume in the cylinder and head I made a perspex cover to bolt on to the block and head, then I injected coloured water with a syringe to get the volume at TDC. Adding a 3 mm spacer plate with the head gasket gives me the ratio I need for this engine.
After making these mods it will not be able to run on normal fuels, just woodgas. It would have been nice to be able to leave the original injection system in place but there is no other place I can fit the spark plugs other than in the injector holes. As I have another Diesel generator this does not bother me.
I am running a generator but all the same would apply to vehicle based gasifier, if you used a turbo charged diesel engine it should have lower compression ratio than a naturally aspirated. In this case you may not need to alter the compression ratio but just limited the boost pressure to stop pre-ignition occurring.
Is it hard to adapt the diesel that way? Also do the converted diesel engines offer any other advantages with wood gas?
How hard is going to depend on what skills you have and the engine. It is certainly far easier to convert a petrol engine.
Diesel engines are built with larger bearings and are more robust so will last longer.