Yeah basically I want to add a bit of colour and a sketchier quality to the drawings to make them a bit more atmospheric and visually bold. I really like the style here, with the sketchy construction lines, and the painted/marker pen colouring style. I'm not too worried about the images on the side, it's the main pot still drawing I'm trying to emulate.
Cheers
You can export the Cad or SketchUp plans as EPS or AI format which you can import into Photoshop.
If it contain dimension lines and are able to edit it in the application used to create it, you can simply change the line weight to make it thinner and change it's fill to a lighter shade before doing the export.
If not, you'll have to use the pencil tool or line tools to create the dimension lines and symbols on a new layer in the imported drawing opened in Photoshop.
You could also add additional sketch lines, use the eraser tool set to airbrush with a lower pressure to fade certain parts of the drawings (like the top end part of the input tube in your sample), use the gradient tool to color the model (this is done on separate layers below the line drawing layer, add sketchy shadow/background or smudged look with the smudge and burn tool and whatever blemishes on the model you may need to give it a sketchy, hand drawn look.