-——some sort of device.....——
insert a lit cigarette into a match pack, pour gas under the vehicle, place the lit cig/matches on the gas . When the cig burns down, the matches ignite the gas and the tires/car burn
That's one trick. These documents describe lots more.
Animal Liberation Front, "Arson-Around With Auntie ALF." This was once available as free download from the ALF web site. It has been removed. However, an Internet search will locate several sources. (Describes various incendiary devices)
Earth Liberation Front, "Setting Fires With Electrical Timers: An Earth Liberation Front Guide, May, 2001." This was formerly available from the ELF web site. It has been removed from the site. However, an Internet search will locate several sources. (Describes electrical igniters for incendiaries)
Those are free. The following you have to pay for.
Department of the Army, Incendiaries, TM 31-201-1, Randle, WA, Bohica Concepts, 1966. Also available from Gold Nugget Army Surplus.
Anonymous, CIA Field Expedient Incendiary Manual, available from Paladin Press. (Good discussion of delay devices)
Whitney, Lyle, "Black Book of Arson," El Dorado, AR, Desert Publications, 1987. (discusses the physics of fires, and how to set them effectively)
Lots of information out there, just in case you ever need it.