Your old tractor will run just fine on any blend of biodiesel, right up to b100 - BUT -
You will need to change ALL rubber hoses for something that is biodiesel safe. You will need to replace any rubber seals in the fuel pump/injector pump/fuel line banjo connections.
The fuel filters will without a doubt clog as the diesel dissolves half a century of dinojuice crud, so buy some spares and have them ready. MAy assist if you put a easy to reach inexpensive filter in the fuel line before the standard cartridge filter.
You may well find that the IP starts to leak. Probable cause is that over the years the dinojuice crud builds up in all sorts of little knooks and cranies and hairline cracks and now, as the bd melts them out, you may find a leak or two.
Hope I have not put you off. If you make your own Bd, to proper specs, the long term advantages work to your benefit as well as the environment.
