What engine modifications would be needed to run pure biodiesel in American school buses? Cost? Thanks!?

Question

If 100% is very difficult, how about 20% or 50%? Economic opportunity for a backyard refiner? Can it really be made from used cooking oil for less than 1$ a gallon?

Answer 1

Some school districts in the US are already doing this.

Answer 2

If you are using 20% biodiesel absolutely no modifications are needed at all.  20% biodiesel can safely be run in any diesel engine.  Here is a good link to read about it :

http://www.sqbiofuels.com/faq.htm#q3

Answer 3

Converting to biodiesel consists of replacing all rubber tubes with plastic. Maybe a few internal gaskets. That's it.

And yes, some guy on The Discovery Channel runs his biodiesel Toyota pickup for 55 cents per gallon, from free cooking oil distilled in his garage 'refinery'.

Answer 4

And after reading the link above, I see the biggest problem is that 100% biodiesel will gel at temperatures colder than 40 degrees F. Other than that, you should be able to use 100% biodiesel in any newer (built after 1993) diesel engine with absolutely no modifications.