Making fuel from plastic is no different than a sill or pyrolysis
How to turn plastic waste into diesel fuel cheaply - Energetic Forum
Depending on your feedstocks you end up with sulphur free k1 kerosene to D3 diesel.
You can use up to about 20% of this “fuel” in an older gasoline engine
Or 100% in an older diesel
The Japanese home appliances called the “Blest machine “ is no longer manufactured but the company is still around