This type of Illustration was my profession before I turned to doing race car paintings. These cut-aways and exploded drawings are now mostly done on the computer using programmes such as Adobe Illustrator, Photoshop and the like.
I was trained the good old fashioned way with pencil and paper and have done a few race car parts manual drawings in the past for companies such as Lola and Hewland. You can see a gearbox cut-away that I did for Hewland in my previous thread -
I was first inspired by the Autosport Technical Illustrator Theo Page and for my paintings, Michael Turner. Today, the best Race car Technical Illustrator is Tony Matthews from Hitchin in England. I do not know if he has a website but his work is sensational, and produced by hand! I know he has produced his work for Reynard, Lola, March, Ferrari, Penske etc,.