hi all. iv been given a rc nitro car that needs a new engine amongst other things. from what iv read different scale models need different size engines, but how do i know the scale of the car? there is no make/model on it as it seems to have been built from a mishmash of parts so i cant look it up. also is there any way to repair an engine that spits out fuel/grease from underneith itself when its runnung? cheers..........